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Biology 101 > Exam 4 pt 2 > Flashcards

Exam 4 pt 2 Flashcards

(79 cards)

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1
Q

Predation

A

a “+/-“ interaction, where the effect is positive on one species (the predator) but negative for the other species (the prey).

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2
Q

Herbivory

A

a “+/-“ interaction, where the effect is positive on one species (the herbivore) but negative for the other species (the plant).
-side note: the plant doesn’t always die

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3
Q

defenses against predators:
(there’s 9 things)

A

-be difficult to detect
-defend yourself with chemicals
-mimic a defended species
-scare/confuse the predator
-be vigilant (watch for predators)
-active defense (like a squid squirting)
-fleeing
-be hard to eat (spines, thorns)
-be in a group

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4
Q

Batesian Mimicry

A

a harmless species mimics a harmful one

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5
Q

Mullerian Mimicry

A

two unpalatable species mimic each other.

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6
Q

Symbiosis

A

An interaction between organisms of 2 different species that involves direct physical contact
-parasitism (+/-)
-mutualism (+/+)
-commensalism (+/0)

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7
Q

Parasitism

A

-(+/-)
-parasite lives in or on a host
-often not lethal
-pathogens

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8
Q

Pathogens

A

-disease causing organisms
-generally microscopic
-can be lethal

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9
Q

Commensalism

A

-(+/0)
-one species benefits, the other is unaffected
-difficult to document, may not be
common
- “hitch-hiking”
-burs, algae growing on turtle
shells
-usually not obligatory
-both species can survive w/out
each other

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10
Q

Mutualism

A

-(+/+)
-host and symbiont both benefit
-plants and pollinators
-relationship often obligatory
-can become extremely close

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11
Q

Endosymbionts

A

-species living inside its host
-origin of chloroplasts, mitochondria

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12
Q

Competition

A

-(-/-) bc there is a negative effect on both species
-occurs when 2 or more species rely on the same resource, and the supply of the resource is limited
-interspecific and intraspecific competition

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13
Q

Speciation

A

-the creation of a new species

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14
Q

Macroevolution

A

-the evolutionary components of speciation

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15
Q

Microevolution

A

-change in allele frequency in a population in time

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16
Q

biological species concept

A

individuals are members of the same species if they are capable of interbreeding and producing fertile offspring

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17
Q

reminder

A

same species may be composed of different subspecies, but mating still successful across subspecies

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18
Q

reproductive isolation

A

the existence of biological factors (reproductive barriers) that prevent two individuals from interbreeding and producing viable offspring

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19
Q

Zygote

A

fusion of sperm and egg

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20
Q

Reproductive barriers

A

-barriers can be pre-zygotic or post-zygotic
-prevent mating (pre)
-prevent fertilization of egg (pre)
-prevent survival, reproduction of
offspring (post)

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21
Q

Mechanical isolation

A

-mating may be attempted but prevented by morphological differences
-pre-zygotic

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22
Q

Gametic isolation

A

-sperm of one species may not be able to fertilize eggs of another species
-pre-zygotic

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23
Q

Post-zygotic barriers: fertilization occurs but…

A

-reduced hybrid viability
-hybrids do not survive well
-reduced hybrid fertility
-hybrid breakdown

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24
Q

Hybrid breakdown

A

hybrids are non-viable or sterile in subsequent generations

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25
Allopatric speciation
-geographic separation of populations -if populations diverge enough, they may become separate species
26
allopatric speciation: how might separation foster divergence?
-greatly reduced gene flow -genetic drift -founder effects -natural selection -differences between two areas
27
Endemic species:
species found only in a particular location
28
Evidence that gene flow is important in allopatric speciation:
-endemic species -greater fraction of endemic species as distance increases -distance likely reduces gene flow
29
Sympatric speciation
-speciation without geographic isolation -most common in plants -most common mechanism= polyploid -'many chromosomes' -can occur in animals -less common -polyploidy is rare -reproductive isolation within the same population
30
Polyploid
-error during meiosis changes # of chromosomes in gametes ---> offspring -offspring may be viable and self-vertile
31
allopatric vs. sympatric speciation
in allopatric: -geographic isolation restricts gene flow between populations -reproductive isolation may then arise by natural selection, genetic drift, or sexual selection in the isolated populations in sympatric: -a reproductive barrier isolates a subset of a population without geographic separation from the parent species -can result from polyploidy, natural selection, or sexual selection
32
how much genetic change is required for speciation?
-impossible to generalize -some speciation events may result from cumulative divergence of many genes -some may result from one or few changes
33
Punctuated equilibrium
periods of little change interrupted by short periods of rapid change -tempo of change is not constant
34
Gradualism
differences between species accumulate through slow, steady change -big changes reflect slow steady change
35
how quickly does speciation occur?
-the interval between speciation events can range from: -4,000 years to 40,000,000 years -average of 6,500,000
36
Adaptive radiation
-are periods of evolutionary change characterized by the formation of many new species -can occur when organisms colonize new environments with little competition -can also arise due to the evolution of a key adaptation
37
Mass extinctions
-boundaries between geological divisions often marked by mass extinction events -5 mass extinction events in geological time (killed off more than 50% of species w each one) -often associated with big environmental change
38
Ecology
the study of the distribution and abundance of organisms -evolutionary time scales: decades--> millions of years -ecological time scales: hours--> year
39
the scope of ecological research
-ecologists work at levels ranging from individual organisms to the planet -there are several sub-disciplines within ecology
40
Dispersal
the movement of individuals away from centers of high population density of from their area of origin -can occur due to natural movement of organisms -can occur due to human activities
41
Herbivores often _________ than ______
herbivores often disperse farther than plants
42
dispersal of _______ in marine systems typically exceeds dispersal of _______
dispersal of propagules in marine systems typically exceeds dispersal of terrestrial plants
43
Why is species X absent form an area? (4 ?'s)
-does dispersal limit its distribution? -does behavior limit its distribution? -do biotic factors limit its distribution? -do abiotic factors limit its distribution?
44
Climate
long-term, prevailing weather patterns in an area -temperature, precipitation, seasonality of conditions
45
climate is a key abiotic factor because it creates
-climate creates distinct biomes
46
Biome
characteristics type of ecological community + climate
47
Density
of individuals per unit area or volume
48
Dispersion
pattern of spacing among individuals in a population
49
density is the result of four processes:
-births -immigration -2 above add individuals to a population -deaths -emigration -2 above remove individuals from a population BIDE
50
Clumped dispersion
Individuals are evenly distributed -may be influenced by resource availability and behavior
51
Uniform dispersion
Individuals are evenly distributed -may be influenced by social interactions such as territoriality
52
Random dispersion
the position of each individual is independent of other individuals -it occurs in the absence of strong attractions or repulsions
53
Demography
study of population attributes and how they change over time
54
characteristics of interest
-demography -composition of the population (aka population structure) -rates that describe population change
55
population structure
-sex ratio -age structure -birth rate -death rate
56
Sex ratio
males : # females
57
Age structure
-relative number of individuals of each age in that population -age groups are often based on reproductive status or some other characteristics relevant for population dynamics -pre-reproduction -reproduction - post-reproductive
58
Fecundity or fertile rate
offspring per unit time -generation time
59
Generation time:
average amount of time between the birth of an individual and the birth of its offspring
60
Cohort
group of individuals born at the same time
61
Survivorship
tracks changes in # of individuals in a cohort over time -survivorship curve
62
Survivorship curve: Type 1:
low death rates during early and middle life, then an increase among older age groups
63
Survivorship curve: Type 2:
the death rate is constant over the organism's life span
64
Survivorship curve: Type 3:
high death rates for the young, then a slower death rate for suvivors
65
Exponential growth
-rate of increase (r) determines speed at which population size increases -eventually, though, explosive growth is always realized
66
are there factors that can limit population size and growth?
-resources become limited -diseases can spread -accidents can happen
67
Controls on population size
-density-independent controls -density-dependent controls
68
Density-independent controls
-can be important at any population size -ex. fire, tornado, drought
69
Density-dependent controls
-importance depends on population size - ex. competition for food, disease
70
Point of population stabilization=
carrying capacity (K)
71
Logistic growth
-exponential growth + a "buffering" term that keep the population at/near the carrying capacity, K -change in population over time -rN* (K-N)/K
72
Interspecific interactions
-predation (including herbivory) -symbiosis (including parasitism, disease) -competition
73
Niche
-the sum total of an organism's use of resources in its environment -how an organism "fits in" to the environment -habitat it uses, temp. it prefers, etc. -another way to state the competitive exclusion principle: no two species in the same community can have the same niche.
74
Avoiding niche overlap
-over time, natural selection should minimize competition -resources partitioning -where you live -what you eat -when you reproduce -character displacement -thought to be a mechanism driving speciation
75
Character displacement
-tendency for characteristics of sympatric populations to diverge more than allopathic populations
76
Tropic structure
who eats what/whom
77
Food chains
-simple linear relationship of who eats whom -tropic levels -plant-> grazer-> primary consumer-> secondary consumer
78
Food web
more realistic representation of trophic structure
79
Tropic cascades
indirect effect of top predators on lower trophic levels

Biology 101 (3 decks)

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