Ecology Flashcards
(485 cards)
1
Q
ecology come from the word
A
Oikos- house, place to live
Ernst Haeckel 1869
2
Q
Ecology interval/range
A
Organsims-Earth (biosphere)
Behavioural ecology– population ecology– community ecology– deep ecology
3
Q
Subsection of ecological genetics
A
genetic variability
natural selection
evolution
4
Q
ecological genetics
A
study of genetic/phenotypic variability in natural populations, relationship to ecological processes
5
Q
If all individuals in a population are homozygous
A
monomorphic
6
Q
If any individual in a population has a heterozygous locus
A
polymorphic
7
Q
Average percent of loci in a population that are polymorphic
A
5-15%
8
Q
genes/individual
A
~20,000
9
Q
Genetic variability
A
percentage of heterozygous loci : population size
increased genetic variability with increased population size
10
Q
Natural selection in moth species
A
evolved to mostly black because lichens were less common on trees after industrial revolution
11
Q
Natural selection of sea snails living on kelp
A
Yellow snails have advantage over predator below kelp
brown has advantage over predator above kelp
due to light source
12
Q
evolution of spirit bears
A
white bears have advantage over darker coloured bears when fishing
13
Q
zygosity in populations <100
A
nearly monomorphic
14
Q
monomorphic populations
A
increases susceptibility to disease
decrease adaptability to environmental change
15
Q
Initial genetic variation vs. generations
A
N = 20, genetic variation = 0 after 200 generations
N=100, variation down to 0.2 ~300 generations
N=1000 small decrease in variation over 500 generations
16
Q
reduced number of individuals in population
A
increased inbreeding– increased homozygosity– increased juvenile mortality
17
Q
MVP
A
minimum viable population
18
Q
minimum viable population
A
smallest possible size at which a biological population can exist without facing extinction
90% of genetic variability after 200 years
19
Q
MVA
A
minimum viable area
20
Q
minimum viable area
A
minimum land area required to maintain genetic variability after 200 years
21
Q
MVP then and now
A
used to think ~500 was viable
now know it must be ~2500-4000
22
Q
most common park size
A
~20-50km^2
23
Q
immigration in regards to genetic variability
A
even a small amount of migration per generation allows persistence of genetic variability
24
Q
no immigrants per generation
A
<60% genetic variability left after 100 generations
25
1 immigrant per generation
~90% genetic variability left after 100 generations
26
natural selection 2.0
non-random and differential reproduction of genotypes resulting in preservation of favourable variants
27
adaptation
physiological, morphological, or behavioural modification that enhances survival and reproductive success of an organism
28
evolution
serial change over time
| descent with modification
29
Anagenesis
gradual change over time
changing adaptations over time
does not lead to species diversity
30
Cladogenesis
branching of lineages and formation of new species
| usually occurs with geographical or genetic isolation
31
anagenesis graph geological time vs. trait condition
relatively straight line
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cladogenesis graph of geological time vs. trait condition
branching tree
33
when life began on earth
first life developed on earth ~3billion years ago
34
total number of species on earth
8-100 million
35
Subsections of behavioural ecology
```
optimal foraging
territoriality
sex and mating systems
group living
life histories
```
36
first hard shelled organisms
542mya explosion of diversity
37
mass extinction
250mya
| ~94% of life extinct
38
diversification of mammals and birds
65mya
39
Foraging decisions
large/small, soft/hard, plant/animal, sweet/sour, uncommon/common, closer/more quality, opportunistic?
40
OFT
optimal foraging theory
41
optimal foraging theory
rules in optimizing choice of food/prey
42
3 subsets of OFT
preference for food with greatest net energy gain
feed more selectively when food is abundant
low quality food only when profitable food is scarce
43
optimal foraging, net energy gain
catching difficulty, amount of prey that can be consumed
44
Pied-wagtail (bird) foraging strategies
beetle size most eaten- not biggest or most common
biggest beetles take longer to eat
7mm beetle provides most calories/handling time
45
intrinsic quality of food
amino acids, fatty acids, salts, vitamins, trace elements
46
importance of sodium
primary extracellular ion, major role in body fluid volume, acid-base balance, tissue pH, muscle function, nerve synapse
47
sodium defficiencies
on average animals are sodium deficient
plants do not contain sodium
why animals are given salt licks
aquatic plants are rich in sodium
48
primary reason for animals to move to coastal regions
compensation for sodium deficiency
49
aquatic plant properties
low calories
high Na levels
high moisture (bulk)
50
Terrestrial plant properties
High calories
Low Na levels
low moisture
51
Aquatic vs. terrestrial plants in moose diet
low terrestrial would require high aquatic intake for energy
stomach not large enough for high aquatic intake
high terrestrial not enough energy or sodium
small range for optimal diet
52
bison foraging strategy
migrate to salt lakes
53
Patch foraging time
food occurs in a patchy distribution and in patches of different size
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optimizing foraging time among patches
concentrate foraging activity in most productive patches
ignore patches of low productivity
stay with patch until profitability falls to level equal to average for all foraging patches combined
55
as time spent in foraging patch increases
energy obtained 'flattens out'
56
leave foraging patch when
probability is that the next patch will be more dense
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time to spend in foraging patch graph
cumulative net food gain vs. time spent in patch
58
if it takes a long time to obtain food
animals spend more time on that food
| birds that open containers easily didn't stay long
59
foraging time vs. predation risk graph
state of hunger dictates willingness to risk predation
starving- straight line, foraging activity is independent of predation risk
very hungry- sloped line, foraging activity decreases linearly with increased predation
slightly hungry- no foraging activity with high predation
60
Home range
area over which an animal travels in search of food/mates/resources and which is not defended
present in majority of animal species
61
territoriality
defines of an area and active exclusion of resource use by others through display, advertisement or defense
62
Territoriality is common in
predators (african lion, cheetah, hyaena, bear, eagle, hawk, owl)
birds during nesting
fish during reproduction
social insects (ants, bees, wasp, dragonfly)
63
Influences on size of territory
body size, aggressive behaviour, habitat quality, population density, competition with others, ability to share resources
64
black-capped chickadee territoriality
male sings to mark territory
| same species avoid each others territory, other species do not (intraspecific competition)
65
Great Tit territoriality experiment
Remove individual 3 to see if there would be a change in territories, boundaries expanded, new arrivals came
was 3 dominant to the others? defended territory more..
66
larger territory =
more food, shelter, reproduction
harder to defend
want largest area with lowest cost
67
determining optimal territory size from benefit/cost vs. territory size graph
optimal size is where there is the largest slope on benefit curve
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maximum territory size from benefit/cost vs. territory size graph
where benefit curve flattens out
69
changes in optimal territory size
ex. predator moves into area
70
Asexual reproduction
offspring genetically identical to parent
common in bacteria, unicellular eukaryotes, plants
occasional in vertebrates
harder for species to persist
71
predictor of asexual reproduction
small, short lifespan animals
| consistent environment
72
asexual species using sexual reproduction at particular stages of life
times of stress
73
Sexual reproduction
majority of species
| genotype different from mother and father
74
in changing environment/niche, new genotypes may have
higher reproductive output than either parental genotype
75
categories of sexual reproduction
dioecious
| monoecious
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dioecious
'two houses' 'two sexes'
male/female organs on separate individuals
~equal sex ratio
majority of species
77
monoecious
'one house'
m/f organs on same individual
bisexual or hermaphrodite
78
types of hermaphrodites
simultaneous hermaphrodite
| sequential hermaphrodite
79
simultaneous hermaphrodite
both sets of reproductive organs at same time
common in plants/invertebrates
can't mate with self
80
sequential hermaphrodites
m/f reproductive parts at different times
| common in coral reef fish
81
ontogeny
origination and development of an organism, usually from the time of fertilization of the egg to the organism's mature form
82
example of simultaneous hermaphrodites
slugs, worms
83
example of sequential hermaphrodite
Wrasse
small ones- genderless
medium- female (beta position)
large- male (alpha position)
84
simultaneous/sequential hermaphrodites don't have
sex determining chromosomes
85
Mating structures
Panmixis
Polygamy
Monogamy
86
Panmixis
unrestricted random mating
all individuals equally potential partners
sexes look alike (monomorphic)
eggs and sperm dropped all over the place
87
panmixis examples
some marine invertebrates
| marine schooling fish
88
Polygamy
many marriages, multiple partners
widespread
sexes look different (dimorphic)
males often larger/more elaborate
89
types of polygamy
Polygyny
| Polyandry
90
polygyny
female defense polygyny- individual males defend groups of females
resource defense polygyny- individual males defend resources which female seek out
91
polygyny examples
fish, amphibians, reptiles, songbirds, mammals
92
female defense polygyny examples
deer, primates
93
resource defense polygyny examples
fish, songbirds
94
polyandry
many males, single/few females
males take on 'mother' roles- incubate eggs, sexually inactive
sexual genes are down regulated
females compete for males and defend resources
95
polyandry example
shorebirds
96
monogamy
serial or lifetime
one marriage, high fidelity to single partner
care for young for a long time, often predators
bi-parental care required to raise young (or they die)
sexes usually look similar (monomorphic)
97
monogamy examples
carrion beetle, most seabirds, swans, hawks, beavers, weasels, wolves
98
new data on genetic fingerprinting indicate offspring of monogamous couples
```
are often sired by more than one father
socially monogamous (cheating)
```
99
extra pair copulations (EPC)
copulation with a male other than the bonded male, gives birth to offspring whose father is not the bonded male
100
fitness of offspring is a function of
who female mates with (genetic makeup)
101
females choosier than males in mate choice
fitness cost is greater than in males (limited eggs 400 vs. unlimited sperm 200 million per ejaculate)
102
sexual selection
mate choice- tendency for individual to be selective in whom they choose to mate with
103
male fitness increased by
maximizing number of fertilized eggs (increased number of females)
104
female fitness is increased by
maximizing genetic quality and genetic variability of their offspring
105
female mate choice criteria
```
nuptial gift
dominant/strong male preference
handicapped male hypothesis
parasite free male hypothesis
symmetric male hypothesis
display evaluation
inbreeding avoidance
```
106
nuptial gift
males provide gift to female to solicit matings
| females use resource characteristics to determine quality of male
107
examples of nuptial gift
hanging fly
thynnine wasp
song birds
108
hanging fly
```
larger prey (gift) = more sperm transferred (longer copulation)
sperm is stored in female, she chooses which to use later
```
109
Thynnine wasp
female doesn't fly, releases scent to winged males
| males ability to carry female to multiple flowers increases probability of male mating
110
songbirds (nuptial gift)
gift to female is safe territory for foraging/breeding
| male evaluated based on length and complexity of song- correlated with territory size (physically demanding)
111
examples of Dominant/strong male in sexual selection
ram
elephant seal
damselfly/dragonfly
112
damselflys dominant sexual selection acts
males engage in aerial combat over pond
winners do the mating
female increases genetic quality of offspring by mating with winner
113
handicapped male hypothesis
expression of costly elaborate display by males provide female the greatest information on genetic quality of male
"honest signal" of fitness, low possibility of cheating
male survives despite handicap
114
example of handicapped male hypothesis
peacock
| widowbird
115
widowbird handicap
male tail is longer than body, reduces flight, feeding ability, predator evasion
116
elephant seal dominant sexual selection act
fight for female attraction
| only the winner mates with females for the year
117
results of widowbird study (handicapped male hypothesis)
lengthened tail of bird- was much more successful reproductively
118
parasite free male hypothesis
differing susceptibility to disease can lead to mortality in young, males without parasite = better immunological genes- improved physiological ability, immunocompetence heritable
119
bright displays- parasite free male hypothesis
bright displays are physiologically costly to produce
parasitized birds can't produce as bright of colours
if females choose these males- provide offspring with genes more resistant to disease
120
proof parasitized birds can't produce as bright of colours?
removal of lice-- birds moult--- new coat is brighter
121
symmetric male hypothesis
bilateral species
| an excellent genotype can correct asymmetries during development
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developmental instability
asymmetries in structure
| minor errors in embryological development and growth
123
can lead to asymmetry
stress, pollutants, parasitism, homozygosity, poor genotype
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symmetric male hypothesis bird study
symmetry was altered in male birds tail feathers
| female switches her favourite to most symmetric male
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symmetric male hypothesis is commonly observed in
insects, fish, birds, mammals
126
symmetry can be evaluated by
sight and sound
127
example of symmetry evaluation by sound
crickets having symmetric (monotone) frequency wing harps- indictor of body symmetry
128
fluctuating asymmetry
random deviation from perfect bilateral symmetry in otherwise symmetrical morphological traits, originates from developmental errors during ontogeny
129
fluctuating asymmetry reflects
inability of a genotype to buffer itself effectively against environmental perturbations
130
symmetric male hypothesis fish study
females have significant preferences for fish with symmetric vertical bars
131
facial asymmetry in rhesus macaques
honest indicator of health
| used in mate choice situations
132
display evaluation
females evaluate quality, complexity, coordination of display (dances, songs)
133
inbreeding avoidance
all animal/plant species in the wild have mechanisms to avoid inbreeding
134
animal species can detect genetic kinship based on
pheromones
135
MHC
major histocompatibility complex
136
what is MHC
~30 genes coding for proteins in cell membranes essential for immune system, 2 different proteins at each gene, each gene multiple alleles, each individual unique, MHC molecules bind to specific receptors and have distinct odours
137
females prefer what in regards to MHC
males with the most dissimilar odour (genotype) to themselves
138
how birth control affects females and MHC
females are attracted to male similar to self-- birth control mimics pregnancy-- want family close
139
MHC based mating preference may be affected by
genetic background, sex, early life experience
140
inbreeding is potentially problematic in all animal species. the major ecological cost of inbreeding is
reduced capacity to cope with environmental changes
141
increased homozygosity is not an ecological cost
it is a genetic cost
142
advantages of group living
```
increased food search efficiency
increased capture efficiency of large prey
increased detection of predators
increased defense against predators
selfish herd theory
```
143
examples of increased food search efficiency in group living
seed detection by songbirds
| fish detection in gulls- repeatedly catching fish signals a good feeding area
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examples of increased capture efficiency in group living
wolves, lions
| african hunting dogs- pack 20 catch ~80,000 kJ/dog/day, threshold number before a large difference is seen
145
increased detection of predators in group living
'many eyes' theory- Hawks have significantly lower attack successes with large number of pigeons present.
1-10 pigeons = 60-80% success
>50 pigeons = ~10% success
146
increased defense against predators
mobbing- ex. small birds can mob owls
147
selfish herd theory
dilution effect- schooling/herding/flocking- if there is an attack on a group it is less likely the attacker will get you
148
examples of species that exploit selfish herd theory
wildebeest, pronghorn, herring, flamingos
149
evolution of selfish herd theory
belted kingfisher in a tree above a lake.. if fish are individual and he has one is his sights the probability that he is looking at that one is 1, if that fish joins a group the probability that he the one being spotted is decreased..
150
Disadvantages of group living
increased transmission of parasites
shared resources and resource depletion
conflicts/stress
151
yellow-eyed junco group living
flock size 1 = lots of predator scanning, decent amount of feeding, no fighting
flock 3-4 = little predator scan, little fights, lots of feeding
flock 6-7 = slightly more predator scan, more fighting, a little less feeding
152
results of yellow-eyed junco study
if groups become too large fighting will take up valuable feeding time
153
reproductive effort
amount of total allocations that an individual makes for reproduction
154
categories of reproductive effort
r-selected
| k-seleceted
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r-selected
high # offspring
high population growth potential
boom/bust cycles
usually short lived
156
k-selected
low # offspring
low population growth potential
stable populations
usually long lived
157
categories of reproductive effort are
```
relational categories (rather than absolute)
species A is k-selected compared with species B
```
158
subcategories of Life History
```
categories of reproductive effort
frequency of reproduction
occurrence of parental care
clutch size and litter size in k-selected species
age of first reproduction
```
159
frequency or reproduction
semelparous
| iteroparous
160
semelparous
single reproduction, breed once and then die
161
iteroparous
repeated reproduction (usually yearly)
162
semelparous examples
most insects, octopus, salmon
163
iteroparous examples
plants, snails, most fish, amphibians, reptiles, birds and mammals
164
occurrence of parental care
absence/presence
| amount
165
parental care absent in
most invertebrate taxa
most fish
most amphibians
most reptiles
166
parental care common in
```
social insects
small fish
dinosaurs
birds
all mammals
```
167
another name for semalparous
'big bang reproduction'
168
precoccial
offspring are born without needing care
169
example of precoccial organisms
caribou babies can run as fast as adults within hours of life
semipalmated plover born with adult size legs
170
occurrence of parental care - amount needed
absent
precoccial
altricial
171
altricial
offspring are born helpless and require extensive postnatal care
172
example of altricial young
social insects, some fish, amphibians, most birds, most mammals
173
clutch size and litter size in k-selected bird species
birds can only lay one egg a day
| all bird species lay fewer eggs in the nest than they are capable of doing
174
David Lack (1948) proposed that
clutch size represents the maximum number of young parents can successfully raise
175
clutch size tends to increase with
geographical latitude
176
why more eggs with latitude
more food, less competition, easier to care for young
177
test of Lacks hypothesis, collared flycatcher
can lay 8, normal clutch 4
chicks- reduced survival first year, reduced egg production as adults
parents- reduced winter survival, reduced egg production next year
178
test of Lacks hypothesis, Canada goose
can lay 12, normal clutch 4, added 1
chick- survival similar
parents- delayed molt, delayed migration, reduced weight next year, female bred later next year
179
results of Lacks hypothesis
clutch size corresponds to maximum number of offspring parents can raise without a net reduction in future reproductive effort
180
difference in collared flycatcher, canada goose study
collared flycatcher feed young 50 times a day
| canada goose does not feed young
181
age of first reproduction
generation time- major variation
182
examples of variation in generation time
fish: guppies 3wks, sharks 30yrs
birds: songbirds 6mnths, albatross 6-10 yrs
mammals: mice 3wks, elephant, whale, human 13yrs
183
fecundity
number of eggs
184
in most plants and ectothermic animals fecundity is
positively related to size
| lay eggs at older/larger stage = more eggs
185
lay 2 eggs and die at 12 months of age, or lay 10 eggs at 48mnths and die, which is a better strategy?
work out by adding up population size over months
| eventually 2 eggs at 12 months has a greater impact
186
how many species breed within first year of life
98%
187
useful to produce early in life?
if higher mortality rate in getting to the older production age (does probability of survival decrease)
188
mule deer in BC
adult size- 3yrs
can reproduce at 2yrs- body growth reduced, increased winter mortality from predators
without predators most reproduce at 2 yrs
189
r-selection life history attributes
development- rapid
reproductive rate/age/type- high, early, semelparous
body size- small
life length - short
competitive ability- weak
survivorship- high mortality of young
population size- usually well below carrying capacity
190
k-selection life history attributes
development- slow
reproductive rate/age/type- low, late, otero parous
body size- large
life length - long
competitive ability- strong
survivorship- low mortality of young
population size- usually at or near carrying capacity
191
essential features of scientific explanation
testability
| falsifiability
192
scientific experiments
evaluate hypotheses (do not prove)
193
population ecology
dispersion, movement, estimating population size, life tables, mortality and survivorship curves, population growth and population regulation
194
dispersion types
regular/hyperdispersion
random
aggregated/clumped
195
regular dispersion
equidistant
| fish school, seabirds
196
random dispersion
individuals distributed without respect to others
| grazing wildebeest, beach clams, forest spiders
197
aggregated dispersion
most common
| 2 types
198
types of aggregated dispersion
coarse grained
fine grained
plants (due to trace minerals left by glacial till)
199
coarse grained aggregated dispersion
clumps separated by large areas
200
fine grained aggregated dispersion
clumps separated by short distances
201
dispersion
how individuals are distributed in habitat
| structured by where resources are
202
dispersion allows
spread/mixing of genetic information
203
reasons for clumped distribution - plants
local difference in microhabitat- soil moisture, nutrients, sunlight
204
reasons for clumped distribution- animals
resources are clumped
| behaviour which facilitates grouping
205
animal behaviours that facilitate grouping (clumped distribution)
social context, family groups, predator defense, shelter
206
types of individual movement
dispersal
| migration
207
dispersal
movement of individual away from place of birth
| leads to geneflow
208
migration
mass directional movement of large number of individuals from one location to next
209
migration examples
salmon, whales, wildebeest, seabirds, songbirds, monarch butterfly
210
grey whales migrate south in the fall
calves have high thermoregulation needs, born in Baja where water is warmer so they can store energy
211
Warbler migration
south in winter for food (no insects in north in winter)
| north in spring- easier to raise children in north (less competition)
212
monarch butterfly migration
migration is multi generational (4 generations for round trip)
adults mate and leave mt.s in mexico in feb, lay eggs on milkweed, die, eggs hatch feed on milkweed, adults migrate north
213
monarch butterfly eggs hatch in
4 days
214
monarch pupation to chrysalis
10 days
215
monarch generations 1-3
adult 2-6 week migration
216
monarch generation 4
south migration, adult 6-8 months
217
why milkweed
cardiac glycoside, caterpillar puts toxin in its skin
218
density
individuals per unit area/volume
219
estimating absolute density
total counts (photographic)
quadrat sampling
mark, release, recapture estimates
220
Peterson/Lincoln index for mark, release, recapture
N = Mn / m
221
variable in Peterson/Lincoln index
N- population size
M- number of marked individuals
n- number of individuals in sample
m- number of marked individuals in sample
222
confidence intervals in mark recapture
sampling must be repeated to obtain decent confidence interval
223
problems with mark recapture
50% of released steelheads die of stress
birds target butterflies marked on wings
polar bears marked with paint couldn't capture prey
224
assumptions for reliable population estimates in mark recapture
population is largely constant over duration of studies
marked individuals have same chance of getting caught
marked individuals do not incur greater mortality
marks are not lost
225
population is largely constant over duration of mark recapture studies
no immigration, emigration, births, deaths
| only possible in short time frame
226
marked individuals have same chance of getting caught
assumption of equal catchability
227
marked individuals do not incur greater mortality
stress-related mortality
| mark-associated mortality
228
problems with flipper bands on penguins
banded birds had 16% lower survival, 39% fewer chicks
229
non-invasive methods of evaluating density
genotyping / genetic fingerprinting
| hair, feathers, faeces, scales, identify individual genotypes
230
Estimating future population
N_t+1 = N_t + B + I - D - E
231
variables of future population equation
```
N_t+1 - individuals in pop. at t+1 year or generation
N_t - individuals in pop at time t
B- births
D- deaths
I- immigration
E- emmigration
```
232
B - births
natality, number of individuals produced
| fecundity / fertility
233
fecundity
ecological concept, number of offspring produced
234
fertility
physiological concept, females ability to produce offspring per unit period of time
235
PPP
primary population parameters
| B D I E
236
demography
statistical study of human populations
237
life tables useful for
estimating mortality rate, survival rates, survivorship curves, average life expectance
238
types of life tables
age specific
| time specific
239
cohort analysis
```
age-specific- group of individuals of same age class
follow specific cohort from birth to death
most useful on short lived species
```
240
cohort
group of animals of same species, identified by common characteristic, studied over time as part of scientific/medical investigation
241
nestling
eggs that hatch
242
fledglings
birds that can fly from nest
243
in order to construct age specific life table
follow cohort from eggs to adults for 1 generation
244
blue tit cohort
50 eggs followed, x eggs lost, y nestlings, x nestlings die, y fledglings, x fledglings die, y new adults, x new adults die, y adults left
245
survivorship calculated
relative to original cohort
| 3 new adults left, out of 50 eggs = 6% survivorship
246
mortality calculated
relative to each stage
| 3 new adults, 30 fledglings = 1 - (3/30) = 90%
247
time-specific life table
```
age structure at single point in time
long lived, large animals
snapshot in time
'static life table'
requires age distribution of a population
```
248
determining age for time specific life table
growth rings- mussels/clams/trees/fish scales
cross section of tooth- large animals
horn growth- mt sheep
249
survivorship in time specific life table
I_x = N_tx / N_t
| number entering age class / total count
250
mortality
```
1000q_x = ( N_tx - N_tx+1 ) / N_tx
number entering age class x, minus number in age class x+1 divided by number entering age class x
```
251
life expectancy
e_x - expected number of additional years of life remaining at any specific age
252
lowest mortality rates
intermediate age- healthiest, predators attack old and young
253
more information in
mortality rate curve than survivorship curve
254
Idealized survivorship curves
Type I
Type II
Type III
255
survivorship curve type I
k-strategists, many mammals, number of survivors relatively constant till later age
256
survivorship curve type II
many birds, small mammals, lizards, turtles, linear with negative slope, probability of survivorship is same each successive year
257
survivorship curve type III
many invertebrates, fish, amphibians, plants, r-stratigists, why they lay so many eggs, largely decreasing survivorship at early age
258
dominant cause of survivorship curve shape
predation
259
atual survivorship curves
are ~same shape, lower (in survivors) than idealized curves
260
population growth
occurs when births (natality) and immigration exceed mortality and emigration
261
ASFR
age specific fecundity rate
262
ASFR =
average number of male and female offspring produced per female for each class
263
TFR
total fertility rate
| average number of male and female offspring produced per female over her lifetime
264
TFR =
ASFR x number of years in age class (range)
265
critical information for population growth
sex ratio- life tables often calculated only for females
266
importance of sex ratio
A=10 reproductive adults, B=100
A produces 9X more offspring than B?
A= 1 male, 9 females
B= 99males, 1 female
267
NRR
net reproductive rate
268
NRR =
Ro = ∑ Ixmx
269
Ixmx
survivorship of reproductive females in any age group * number of daughters produced for each age class of female
270
Ro
number of breeding daughters that will be produced by each breeding female in the population per generation
271
Ro < 1
population is decreasing
| each female produces ~<1 breeding daughter by end of reproductive period
272
Ro = 1
population is stationary
273
Ro > 1
population is increasing
| each female produces ~>1 breeding daughter by end of reproductive period
274
if Ro = 1.33
population of 100 females will grow to 133 females per generation
275
population growth without restraint
geometric growth
276
if Ro is unknown
use lambda- geometric rate of increase, finite multiplication rate, finite rate of increase
277
lambda =
N_t+1 / N_t
278
estimate geometric growth of population in to future
N_t = N_o * lambda^t
useful for non overlapping (discrete) generations
semelparous species
279
population growth of iteroparous species
```
dN/dt = rN
dN = rate of change in numbers
dt = rate of change in time
dN/dt = rate of population increase
r = per capita rate of population growth (intrinsic rate of natural increase)
N = population size
```
280
r ??
b - d
number of births/thousand yrs
number of deaths/thousand yrs
281
alternative estimation of r
r ~ ln Ro / Tc
| Tc = generation time, mean time elapsing between birth and first reproduction
282
If r < 0
population declines
283
If r = 0
population is stable
284
if r > 0
population increases
285
to determine N at some point in future, for population with overlapping generations
N_t = No * e ^ rt
286
overlapping generations vs. discrete generations
over. Nt = Noe^rt
| discret. Nt = No*lambda^t
287
projected population in 100 years if r=0.01 and No = 7 billion
19.6billion
| Nt = No e^rt
288
why can populations not grow indefinitely
finite resources run out
| renewable resources are limited
289
K
carrying capacity
290
carrying capacity
total numbers of individuals of a species that be sustained in a habitat in the long term
291
determining carrying capacity
often estimated indirectly as the average population numbers of the species observed across multiple years
many factors are involved, usually determined in hindsight
292
logistic growth
population 'flattens out' as it approaches K
293
types of / variations in logistic growth
```
ideal logistic growth (smooth response)
damped oscillations (up and down before settling at k)
stable limit cycle (up and down around k without settling)
chaotic (extreme up and down, rise and crash)
```
294
logistic growth equation
dN/dt = rN [ ( K - N ) / K ]
295
carrying capacity of habitat is influenced by
most limiting resource
296
if populations exceed K
resources decline-- morality increases-- birth rate decreases-- population decreases
297
factors limiting population growth
density-dependent population regulation
| density-independent population regulation
298
density-dependent population growth
due to intrinsic (natural) factors
| due to individuals (birth rate, mortality)
299
mechanisms for density-dependent effects when population exceeds K
```
intraspecific competition
delayed breeding/reduced offspring production
territoriality
dispersal
parasites/disease
predators
```
300
intraspecific competition (populations exceeding K)
occurs when required resources are in limited supply (food, space, mates)
301
types of intraspecific competition
interference competition
| differential ability to secure resources
302
Inference competition
individuals interfere with others for limited resources
| leads to one individual having less
303
examples of inference competition
gulls stealing from others
| lions excluding others from a kill
304
differential ability to secure resources
law of constant final yield- only a certain amount can be sustained in certain area, ex. start with 1000 or 100 plants, end with ~same amount
305
delayed breeding or reduced offspring production (populations exceeding K)
applicable to almost every bird and mammal
| increased population = agonistic encounters = stress-- females reabsorb embryo
306
agonistic
combative, conflicting, aggressive/submissive interaction
307
how stress can be birth control
stress triggers hyperactivation of hypothalamus, pituitary and adrenocortex- alters secretion of growth and sex hormones-- suppression of body growth, reproduction, immune system-- pregnant females enlarged adrenal glands, kidney inflammation, uterine mortality, reduced lactation
308
young born to stressed mothers
low body weight, poor survival, delayed puberty, low reproductive rate
309
delays puberty in juveniles born during periods of high population density
odour of female urine
310
increased territoriality (populations exceeding K)
territorial defense by dominant individuals leads to reduced access to resources by sub-dominant individuals
leads to reduction in # of non-territorial individuals (reduced reproduction)
311
dispersal (populations exceeding K)
migration
w/o migration population exceeds K and crashes
with migration population can 'flatten' at K
312
example of parasite/disease controlling population
Myxomatosis introduced in European rabbits in Australia, 99% mortality
313
example 2 of parasite/disease controlling population
gastrointestinal nematodes-- reindeer-- negative impact on female reindeer becoming pregnant-- parasites have potential to regulate population dynamics-- in presence of parasite populations = stable dynamics
314
average number of parasite species per host
```
fish ~2
birds ~8
mammals ~15
bugs, beetles, flies 4-6
butterflies, moths ~10
trees 95
```
315
Predators (populations exceeding K)
major source of mortality in survivorship curve
| increased density of prey = predator expansion = proportionately greater predation on prey
316
parasitic wasp
~1mm, lays one parasitic eggs in each aphid, rapidly controls population
317
analysis of density dependent population regulation
parasites and disease - ~50% insects
predators - ~40% insects
mortality from limited food- ~40% small mammals/birds, ~50% insects, ~90% large mammals
mortality from limited space- 100% small mammals/birds
318
density-independent population regulation
reduction in carrying capacity of habitat
mainly due to extrinsic factors
mortality due to severe external conditions
mostly independent of NK
319
examples of density-independent population regulation
winter, severe draught, fire
320
lynx abundance
correlated to snowshoe hare abundance- increased food source
321
snowshoe hare abundance
correlated with 11yr cycles sunspots-- higher solar output, more plant life, more food for winter
322
why don't hare, lynx, sunspot curves match all the time
many factors are working together- plants produce anti-grazing chemicals, lynx produces stress changes in hares, hares reproduce less
323
a population of 50 female deer with stable age distribution has a Net Reproductive Rate of 1.1, if generation time is 2yrs, population is increasing by how many female individuals per generation
2
324
if population = 50, NRR = 1.1, generation time = 2yrs, population increases by 2 individuals per generation, how many will there be in 20 years?
130
325
anti grazing chemicals
phenols, bitter, less delicious, less nutritious
326
subcategories of interactions
competition, niche concepts, predation, defenses
327
Interspecific competition
any use or defense of a resource by one species that reduces the availability of that resource to other species
328
resource
any substance that leads to individual/population growth if substance is increased
329
resources
food, water, trace elements, space, elements (O2, CO2)
330
is air a resource
not generally (unless it was limited)
331
Liebigs law of the minimum
we often don't know what the limiting resource is
332
what did Justus von Liebig do
discovered that nitrogen is the major nutrient for plants
333
competitive exclusion principle
Gause's Law of competitive exclusion
| 2 species with same niche cannot coexist
334
Gause's discovery
paramecium grown separately had logistic growth curves, grown together one species crashed, one species always outcompeted the other
335
evidence of interspecific competition
habitat shifts in allopatry and sympatry
character displacement and resource partitioning
habitat differences and resource partitioning
allelopathy
336
character displacement
feeding structures, breeding times, changing bill size, displacement of characters reduces competition
337
alpha
competition coefficient
per capita competitive effect of species 2 on species 1
measure of inhibitory effect "
338
alpha = 1
one individual of species 2 equals one individual of species 1
339
alpha = 0.1
then 10 individuals of species 2 equals one individual of species 1
340
total competitive effect of species 2 on species 1 =
alpha * N2
| N2 - population size of species 2
341
competition model
dN1/dt = r1N1 [ (K1 - N1) - alphaN2] / K1
342
to coexist 2 species must have
alpha ~ 1.3 difference (ratio) in feeding parts
343
paradox of the plankton
limited range of resources supports wide range of planktonic organisms, paradox results from competitive exclusion principle, which suggests when 2 species compete for the same resource, only one will persist
344
grain beetle competitive exclusion
just a 3.2ºC difference in habitat switches competitive ability of two beetle species
345
allopatric speciation
populations of same species become isolated from each other, prevents genetic interchange
346
sympatric speciation
new species evolve from single ancestral species while inhabiting same geographic region
347
habitat shifts in allopatry and sympatry
allopatric populations habitat whole area, sympatric populations stick to one area, ex. when fish species are mixed one species lives in middle of lake, other around edges and bottom
348
character displacement (interspecific competition)
two allopatric species have same size feeding structures
| species in sympatry have different size feeding structures
349
hutchinsons ratio
character displacement, size differences between similar species when living together compared to when isolated
350
average hutchinsons ratio for sympatric species
1.28
351
sympatric monkeyflowers (reproductive character displacement)
mean divergence of reproductive structures was greater in sympatric than allopatric, P values of reproductive structures <0.05
352
types of habitat differences and resource partitioning
the ghost of competition past
| competition in the present
353
the ghost of competition past
at some point in the past, several species inhabited an area, all of these species had overlapping niches, through competitive exclusion, the less competitive species were eliminated, leaving only the species able to coexist
354
example of ghost of competition past
desert plants- developed different root systems to coexist
355
competition in the present
exotic species- artificially introduced, displacement of native species
356
examples of competition in the present
European starlings introduced to New York, most common nesting bird in US and south Canada, Scotch Broom from Europe threatening Vancouver island
357
allelopathy
chemical competition in plants and animals
| release of chemicals by one species in order to reduce growth/survivorship of another
358
examples of allelopathy
```
antibiotics, poisons
penicillin by mild
jug lone by black walnut tree
terpines by salvia
corrals produce defenses to stop overgrowth from others
```
359
juglone
highly toxic, kills/injures other plants species within 20m, toxic to herbivore insects, reduces growth of weeds
360
species resistant to juglone
corn, maple, birch
361
salvia study
salvia produces terpines when predation is a problem
| doesn't when it is not (when caged)
362
habitat
physical place where an organism lives
363
niche
how an organism makes its living (carnivore, herbivore)
364
Elton's niche
the role of a species in a community
365
Hutchinson's niche
all biophysical conditions that characterize the life of a species
366
fundamental niche
entire multidimensional space that represents the total range of conditions within which an organism can function without limiting factors (prospective ecospace)
367
realized niche
actual multidimensional space that a species can occupy taking into account biotic factors such as predators, competitors and parasites (actual ecospace)
368
variable in quantifying niche space
```
d = distance between two species in average resource use (peak to peak, between species)
w = measure of resource spectrum breadth of a species (peak to one side of curve, each species)
K = resource availability
```
369
d/w < 1 (quantifying niche space)
no co-existance
370
d/w > 1 (quantifying niche space)
full co-existance
371
resource spectrums
most species have narrow resource spectrum
specialists have VERY narrow resource spectrum
ex. pandas only eat bamboo
372
Hutchinson's concept of niche space
viewing overlap between species in multi dimensions
ex. foraging height, size of prey, time of day
n-dimensional hypervolume
increases organisms ability to coexist
373
biophagy
predation
374
types of predation
carnivory
herbivory (grazing, browsing)
parasitism (pathogens, parasitoids)
detritivores (dead plant/animal)
375
FRC
functional response curves
376
Functional response curves
rate of food consumption and density of prey
| FRC#I, FRC#II, FRC#III
377
FRC#II
positively sloped, flattens out
single prey species
consumer is limited by its capacity to process food
only needs so much , satiated, caloric requirements met
378
FRC#III
standard logistic curve
multiple prey species
increases slower than II
379
threshold of security
occurs when there are multiple prey species
| minimum density under which no further predation occurs- asymptote at lower end of curve
380
why threshold of security
when there are a rare amount of prey, go to new location or find other prey species to consume
381
FRC#1
increasing linearly
single prey species
assumes time needed by consumer to process food is negligible, consuming food does not interfere with searching for food
mostly theoretical, can apply to species with very high metabolism
382
low prey densities
reduced search efficiency
prey switching
search image
aggregated responses of predators
383
search image
predator develops 'image' of what to search for based on first prey it sees (likely most common)
384
proportion of prey population taken by predator predicts that
predators are rarely able to overexploit the prey
385
age class of prey taken by predators
virtually all predators target juveniles and post-reproductive adults
lowest cost of injury
386
salmon field study (removal of predators)
removal of predatory birds- twice as many smolts made it to ocean but same number returned, exceeded carrying capacity
387
grouse study (removal of predators)
removal of predators had no effect on grouse population
| 'law of minimum', prey not controlled by predators
388
mink predation on muskrat populations
most predation occurred on muskrats that had sen excluded from territories due to infraspecific competition, predators took prey where N>K
predators did not control population
389
wolf predation on caribou
without wolves caribou exceed K and population crashes
wolves keep caribou numbers from exceeding K
predator controls prey population in some sense
390
Isle Royal
wolves all homozygous, been studied since 1959, going extinct, moose population greatly increasing
391
parasitic wasp
2 stings to adult cockroach, 1 buckles front legs, 2 into brain, uses sensors along stinger to guid through brain, venom eliminates escape reflex, wasp leads cockroach by antennae, 'zombie' led to wasps burrow, wasp lays egg on underside of cockroach, plugs up burrow, egg hatches, larva chew hole in cockroach and climbs in, grows inside, devouring
392
do predators limit/control prey density
in some circumstances
no if Leibigs law of minimum is acting
yes if carrying capacity has been exceeded
yes but limits tendency of prey population to exceed K
yes when native prey have no defences against non-native predators
393
dingo - kangaroo relationship
no dingos = higher density of kangaroos present
394
dingo - wild pig relationship
with dines absent, biggest increase in population density was in babies
395
the biomass ratio of predator to prey in a community of endothermic predators and prey would be
~ 1:250
396
why is endothermic biomass ratio so high
endotherms have high energy requirements for thermoregulation
397
ectotherm biomass ratio
20:100 (1:5)
398
exploitation rate of prey by predator
average 5% for each predator species (mostly new born and old)
399
exploitation rate is low because
there are multiple predators per prey
| why predators can coexist
400
increase in exploitation can be seen
up north (less predators)
401
highest exploitation rate
humans.. by far
| only predator that take reproductive adults (target the reproductive capital)
402
escape tactics
camoflouge, disruptive colouration, crypsis, aposematic, mullerian mimicry, batesian mimicry
403
aposematic
be conspicuous
advertising poison/pain
predators learn to minimize contact
warning signal
404
mullerian mimicry
many poisonous species develop same conspicuous colour patterns (mimic each other), similar patterns among poisonous species (7 poisonous butterflies with same colour pattern)
405
batesian mimicry
non-stinging/edible species mimics stinging/poisonous species, very precise
ex. hoverfly mimics yellowjacket wasp
406
post-capture defenses
speed, agility, stamina, protean behaviour, autotomy-limb release, spines/armor/behaviour, reflexive bleeding, venomous
407
protean behaviour
unpredictable escape response (predator can't adapt)
| one of most common escape responses of prey
408
autotomy
lizard removing tail, crab releasing claw
409
reflexive bleeding
beetle with 2 separate chemical pouches, can combine them and spray at predator- hot, chemical reaction, blinding
410
effects of herbivory on plants
defoliation
loss of plant vigour, loss of competitive ability
young leaves consumed first (less lignin, most nutrients)
growth rate of plant reduced by up to 25%
411
young leaves consumed first
less lignin
most nutrients
less bitter
taste better
412
plant structural defenses
cactus spikes- protect water supply
413
plant chemical defenses
```
unpleasant odour
contact irriation
bitter taste
neurotoxins
proteinase inhibitors
growth hormone mimics
psychotropic effects
```
414
anti-browsing chemicals
alcohols, alkaloids, quinones, glycosides, flavenoids, raphides
415
plant unpleasant odour
mustard
416
plant contact irritation
poison ivy
417
plant bitter taste
very common
| Red Ceder- tannins
418
plant neurotoxins
dinoflagellates (marine algae), paralytic shellfish poisoning
419
plant proteinase inhibitors
cotton, chickpea, potato
| stops digestion
420
growth hormone mimics
catnip:
nepetalactone (mosquito/tick repellant)
iridodial (attracts aphid eating lacewing)
421
psychotropic effects
peyote (mescaline)
marijuana (THC)
coffee (caffeine)
422
animals utilizing anti-browsing chemicals
monarch butterfly- milkweed
| poison dart frog- leaf cutter ant
423
antibrowsing compounds in spider food
mescaline-- irregular web
| caffeine-- VERY irregular web
424
selective browsing of plants with anti browsing compounds
leaf veins are under positive pressure with toxins
| don't bite veins!
425
animal defense against plant chemical defenses
mixed function oxidaze
concentration of toxins
selective browsing
426
top anti predator mechanisms
1. chemical- reflexive bleeding, toxic chemicals 46%
2. fighting- stinging, biting, kicking, 11%
3. crypsis- camoflouge 9%
4. escape- running/flying, 8%
5. mimicry- batesian/mullerian, 5%
427
interaction categories
competition, niche concepts, predation, defenses
428
ecological succession
continuous unidirectional sequential change in the species composition of the community
429
primary succession
initial establishment of plant and animal communities on substrates lacking living organisms
ex. bare rock, lava, sand dune, glacial melt pond, rainwater
430
alder trees
fix nitrogen, can grow on bedrock
| die, make soil, others can grow
431
ecological succession
1º - from original material (rock slide/lava)
| 2º - change of an established community
432
secondary succesion
ponds/lakes accumulate sediment
vegetation develops on shoreline
eventually replaced with terrestrial community
433
each sequential community in ecological succession
seral stage
434
climax
last serial stage that has long duration and changes very slowly
435
early stage succession of pond
sedges and reeds, quaking bog
436
seral stage
not discrete stage
| not always sequential, cycle back due to environmental factors (flood, fire, heavy storm, volcano, glaciation)
437
identifying succession
yearly pollen influx settles to bottom of pond
take core sample
identify pollen species
438
reconstruct vegetation history
radiocarbon dating
amplify minute quantities of DNA
animal/plant species determination
439
radiocarbon dating
CO2- >99% C12
| C14, half life 5730yrs, decays to 14N
440
sedaDNA
securely dated DNA, molecular presence of species that appear absent in macro fossil record
441
allogenic succession
abiotic disturbance
442
autogenic succession
biotic disturbance
| beaver dam, virus outbreak, invasive species
443
lodgepole pine
has been replaced by douglas fir
| from pond sediment cores
444
species richness vs. seral stage
increases linearly to maximum, flattens out
445
young forest
high plant diversity, low animal diversity, very dense, low sun, few habitats
446
mammal/bird species diversity in forest after clear cutting
summer- immediately after, very high, dips, rises again
| winter- immediately low, increases, flattens
447
total biomass in seral stages following clearcutting
large increase, small decrease, levels off
448
why decrease in total biomass following clear cutting
takes time for decomposers to reestablish, break down biomass
449
problem with reestablishing clear cut forest
takes time for soil community to reestablish
450
reestablishing communities in warm/wet climate
~100 yrs
Krakatau near Java
15m hot lava
451
reestablishing communities in cold/dry climate
~20,000 yrs
Yukon
glaciation
452
secondary growth forests have
almost no predatory insects
| ~1000 yrs to reestablish insect communities
453
ecological mechanisms for succession
stochastic events
facilitation
inhibition
tolerance
454
stochastic events (ecological mechanisms for succession)
unpredictable, who gets there first
455
facilitation (ecological mechanisms for succession)
species creates conditions favourable for a succeeding species but not itself
major process in early stages
leads to assembly rules
456
facilitation example
clover growth without soil-- clovers produce soil for other plants to grow which shade out clover
457
assembly rules
regular and sequential shift in species
| species B cannot establish till species A is present
458
examples assembly rules
predators cannot colonize successfully unless prey are present
pollinators can not colonize successfully unless flowering plants are present
459
inhibition (ecological mechanisms for succession)
species inhibits the colonization of subsequent colonists
| slows succession and prolongs a seral stage
460
inhibition examples
allelopathy- plants/corals
| competitive exclusion- intertidal communities
461
gigartina abundance
red marine algae- high density if Ulva removed, low if Ulva present
462
tolerance (ecological mechanisms for succession)
members of serial stage are those that co-exist due to use of different resources
combines facilitation + inhibition = ghost of competition past
463
early seral stages
```
seed dispersal - good
plant efficiency low light- low
resource acquisition - fast
biomass- small
stability- low
diversity- low
species life history - r
seed dispersal- wind
seed longevity - long
shoot to root ratio- high
```
464
late seral stage
```
seed dispersal - poor
plant efficiency low light- high
resource acquisition - slow
biomass- large
stability- high
diversity- high
species life history - k
seed dispersal- animals
seed longevity - short
shoot to root ratio- low
```
465
trophic levels
the sequence of steps in a food chain or pyramid
466
what are the trophic levels from lowest
primary producer-- primary consumer-- secondary consumer-- tertiary consumer
467
why trophic levels (food chains) are unrealistic
because real life situations involve food webs
468
what determines food web complexity
number of trophic levels
chain length
connectance
linkage density
469
what is chain length (in food web complexity)
number of links running from a primary producer to a top predator
470
what is conductance (in food web complexity)
actual number of links in a food web divided by the total number of possible links (N)
471
N = (in food web complexity)
[ n (n - 1) ] / 2
472
linkage density (in food web complexity)
number of links per species
473
has the largest effect on a system (food web)
species with high linkage density
474
types of trophic pyramids
by numbers
by biomass
by energy
475
number trophic pyramids
how many individuals per trophic level- tertiary consumer is on top (1 consumer : 250 prey)
how many individuals are supported- top is biggest level, bottom is small (one tree maybe)
476
dominant species
a species with an effect on the community proportional to its biomass
477
umbrella species (indicator species)
species used for conservation decisions, supporting an umbrella species can save the ecosystem
478
examples of umbrella species
grizzly, panda, spotted owl, Garry oak
479
example of dominant species
cod
480
keystone species
a species with an effect on the community that is disproportional to its biomass or abundance
481
example of keystone species
sea otter- without them sea urchins take over-- eat kelp-- nursing grounds collapse-- entire sub tidal community shifts
482
keystone molecule
DMS- dimethyl sulphide- produced when plankton feed on algae-- attract bird/fish-- they poop--nutrients increase algae growth
483
the major advantage to breeding earlier in life rather than later is
is shortens generation time
484
experimental removal of fish eating birds from a salmon river in eastern Canada led to which important ecological observation?
number of adult salmon returning to the river did not change
485
today, there are about 7billion humans on the planet. the yearly mortality rate is ~1% and generation time is about 15years. If each female produced one daughter in her life, the earths total population would be closest to which one of the rolling in 50 years assuming these rates remain similar
4 billion
