midterm 1 material Flashcards
(254 cards)
1
Q
Define ecology
A
the branch of science dedicated to the study of the relationships between organisms and the environment
2
Q
Why does evolution matter for ecology?
A
because it is produced bye ecology- the relationship between organisms and their environment
3
Q
Do changes in an organism happen at the individual or population level?
A
Changes in an organism happen at a population level
4
Q
What is the first tenant of natural selection?
A
That not all organisms within a population can survive due to lack of resources.
5
Q
How did the galapagos finches mutate to better suit their environment?
A
At first the change in beak size was a random genetic mutation, however as the trait was considered “fit” for the environment it is pushed to dominate a population due to the mechanism of selection.
6
Q
Define evolution
A
Is the change over time in the proportions of individual organisms that differ genetically. For example, having change of finches having big beaks- so a portion of individual organisms- finches, that differ genetically, change over time.
7
Q
Define microevolution
A
Change over time in gene frequency (how much a population has a certain allele) within a population (ie within a species)
8
Q
Define Macroevolution
A
is change over time in the proportions (populations) of species which results in diversification of taxonomic groups. It involves new or different species.
9
Q
What’s the difference between micro and macro evolution?
A
Diff between micro and macro is whether we’re looking within a species, or in multiple species.
10
Q
What are the processes that create new types of organisms, and at what level do they work?
A
In microevolution, it’s mutation
In macroevolution, it’s speciation
11
Q
What is mutation?
A
A gene gets mutated which causes trait variation in an offpsring
12
Q
What is speciation?
A
is when a new species is formed due to isolation in a population, which causes proportions of populations to change over time through natural selection which acts on the process of mutation and eventually become a new species.
13
Q
What is genetic drift?
A
is when proportions of individuals vary in features due to mutation.
For ex: If two aA organisms reproduce and produce 3 kinds, the ratio of Aa can change from 1:1 to 1:2, this is an example of genetic drift
14
Q
What is natural selection? IGNORE
A
Is when fitter traits are driven forward and remain, leading to proportions of populations to change over time.
15
Q
What is adaptive radiation?
A
is the rapid evolution of a species which results in a diverse group of species when new resources are available, when new challenges need to be overcome, or the when a change in environment opens new environmental niches.
16
Q
What are the processes that alter the proportions of different types of organisms, and what level do they work?
A
On a micro scale- it’s genetic drift and natural selection
On a macro scale- it’s adaptive radiation
17
Q
What evolutionary processes involve ecological interactions between
A
18
Q
What is natural selection?
A
it is differential genetic contributions by particular phenotypes to the next generation, so basically organisms with certain phenotypes will be more likely to pass on there genes and organisms with other phenotypes will be less likely (and due to this there will be variation in genetic contribution among these phenotypes to the next generation).
19
Q
What are the differences between natural selection and genetic drift?
A
natural selection is not random, natural selection depends on both the genotype and phenotype- genetic drift is just genotype, natural selection involves ecological interactions (so the environment is important) and natural selection also results in adaptation (more successful organisms will reproduce more)
20
Q
What is plasticity?
A
variation in the genotype, genes from parent can show in you but you’re environment shapes how highly that gene is presented.
21
Q
What is the first key aspect of natural selection?
A
That more offspring are produced each generation then can be supported by the environment
22
Q
What is the second key aspect of natural selection?
A
That there is variation in physical, physiological, and behavioral traits among individuals in a population- some of this variation is inheritable and this is what’s important!
23
Q
What is the third key aspect of natural selection
A
That some traits will give some individuals an advantage over the other members of the population, this increases their fitness as individuals who possess those traits will have a higher chance of surviving and reproducing then everyone else.
24
Q
What is the fourth key aspect of natural selection?
A
Traits that result in increased fitness will become more common within a population over subsequent generations.
25
What is fitness?
this is the contribution of genes to the next generation by a phenotype in their environment- ie the amount a particular organism with a specific phenotype reproduces and lives.
26
Is measuring fitness the same for all organisms? How would you measure the fitness of plants? What about insects?
No as different organisms have a different means of reproduction and some organisms have long life spans naturally but might not reproduce and therefore wouldn't be fit. For plants, you could look at how many times the plant fruits and how many seeds it produces, you can't just look at how long it grows cause if it's a tree that might be very long but it might not be fruiting.
For insects you could look at how many eggs one produce and also the life span of those eggs after they hatch.
27
What conditions are needed for natural selection?
You need genetic inheritance, so genes get passed on
You need phenotypic variation- so we have actual characteristics being expressed, and we need fitness differences associated with different phenotypes.
28
Is natural selection trying to accomplish something?
No
29
What is adaptation?
the process by which populations of organisms evolve in such a way as to become better suited to their environment as advantageous traits become predominant.
30
What is the selection gradient when it comes to natural selection?
It's how fitness varies when there's variation in a specific phenotypic trait. For example does intermediate variation lead to high fitness? The trait can be size for ex.
31
How many types of selection gradients are there?
4
32
Describe a stabilizing selection gradient
This a selection gradient in which the highest proportion of the population has an intermediate trait size and the fitness of individuals is best at that trait size. After selection the mean stays the same with less variation around it as less fit individuals have reproduced less.
33
What is an example of a stabilizing selection gradient?
An example of this is mice, mice can be white or they can be black, want a brown mice so the chances of camouflage are higher as it’s not either of the extremes. Since this trait is better the fitness is optimal at the intermediate variation.
34
Describe a directional selection gradient?
This is when the population has increased fitness at extremes of a trait, for example the low variation of a trait has the highest fitness. This causes the mean of the trait variation to shift to the left or right (small or large trait size) after selection and causes the variation around the mean to decrease as individuals without the extreme trait size die after selection
35
What are some examples where directional selection occurs?
For example birds with large beak sizes allows them to eat thicker seeds which are populous in the environment, so the next generation will reproduce in that direction.
36
Describe disruptive selection?
Is when fitness is highest at both extremes of the trait, either really high or really low. After selection this causes the porportions of the organisms to increase at the really high trait size and really low trait size (ie bimodial distribution). The mean trait size here does not change as both the extremes are increasing (so they cancel out), but the variation on the mean increases as the extremes (of very small and very high) become larger and larger.
37
What's some examples where disruptive selection occurs?
Male salmon size, oyster color (only white and black oysters can camofluage well)
38
Describe frequency dependent selection
This happens when the fitness of a trait depends on the frequency of other traits in a population. For example, in positive frequency dependent selection, the fitness of a phenotype increases when it's common, in negative frequency selection the fitness of a phenotype decreases as it becomes more common, and therefore is increased when rare.
39
Give an example of frequency dependent selection
Orchids is an example of this, orchids don't give a reward for pollinators, but exhibit different colors, this is so pollinators can hit the different coloured orchids and then become attracted to the rare colour orchid thinking it has a reward. This is an example of negative frequnecy dependent selection.
40
What are the four important characteristics of a species?
Must be a collective group of individuals, must have common ancestry, must be able to breed together, and must have genetic integrity (a discrete gene pool so they don't breed w other species)
41
Why isn't there a single definition for species?
Because species are products of dynamic processes as constantly change, for example some individuals might have common ancestry but are separated by generations so they can't breed, and also some members of species can be asexual organisms which are clones that can't breed but we don't consider each clone a new species.
42
Define cladogenesis
Is the branching of an evolutionary lineage due to speciation.
43
How can reproductive isolation occur?
Can happen physically ie stream between two pops or natural selection and genetic drift can affect traits and if it effects reproductive traits then reproductive isolation can occur.
44
What are the three types of speciation?
Allopatric, parapatric, and sympatric
45
Define allopatric speciation and it's root words
“Allo” = different, “patria” = country
Allopatric speciation = separation of populations is large relative to dispersal distances. So it happens when a single pop becomes spatially subdivided into multiple sub populations through barries like a lake. This causes the separated pop to evolve independently and adapt to their local environments.
46
Parapatric speciation defn?
occurs when a population expands into a new habitat within the pre-existing range of the parent species. for example some individuals from the parent poop can live in the lake near by due to certain mutations, if these individuals and the parent pop don't breed speciation can eventually happen.
47
Define sympatric speciation and it's root words
“sym” = same, “patria”= country
Sympatric speciation = development of
reproductive isolation between two segments of a single population that are in continuous contact.
This can happen for example in disruptive selection where in one pop two distinct phenotypes are doing very well and then they only mate with organisms with their phenotype eventually leading to reproductive isolation
48
Define physiological ecology
The study of the biophysical, biochemical and physiological processes used by plants and animals to cope with factors of their physical environment, or employed during ecological interactions with other organisms.
49
What are the two types of abiotic factors?
resources and conditions
50
Whats a resource (in terms of an abiotic factor)
A resource is an abiotic factor that is consumed or used by an organism (food, water) or made less available to others (space).
51
What's a condition (in terms of an abiotic factor)
A condition is an abiotic factor that changes in time and space as is something organisms respond differently too.
For example: Temperature of a room, humidity in a room
52
Describe how temperature is an abiotic factor and it's signifcance?
varies in time and space, and is very significant as climate change changes this. Organisms respond to changes in temperature very different way.
53
How is water availability an important abiotic factor?
Because all organisms contain water, all organisms give energy to maintain their water and dissolved products in it.
54
What are some environmental stressors?
Environmental stressors may include climate change, nutritional variability, and disease.
55
What are poikilotherms?
Are organisms whos internal body temperature fluctuates with the external temperature of the environment.
56
A salmon in a lake has an initial internal body temp of 30 degrees, the lake becomes warmer near a hotspot that the salmon swims too, the salmons internal temp becomes 35 degrees, what kind of organism is it?
It is a poikilotherm
57
What is a homeotherm
This is an organism that maintains it's internal body temperature regardless of the external environment temperature.
58
A monkey has an internal body temperature of 60 degrees, it goes into a really hot part of the forest and stays for hours, it's temp is checked again and it's 60 degrees, what kind of organism is it?
A homeotherm
59
Define a heterotherm
is both a poikilotherm and a homeotherm.
60
What are the two names that describe how an organism regulates it's body temperature?
can be ectotherms or endotherms
61
What is an ectotherm?
Ectotherms regulate their body temperature by travelling to environments with the appropriate temp.
62
What is an endotherm
An organism that regulates it body temperature through metabolic processes.
63
Can an endothermic animals also pick spots that aid in regulation of body temperature?
Yes! even though they use metabolic processes to regulate their body temperature they help aid this process by sitting in sun rather than the shade for example.
64
What is torpor
this is a mechanism that animals which regulate their internal temp use to drop their temp under certain condition. They do this by slowing down their metabolism. Occurs only in some mammals and birds.
65
What's an example of an endo heterotherm?
bumblebees, as they maintain internal temp of their thoracic, but they give up internal temp regulation of their abdominal as it needs it less. Since they're maintaining temp in one body part using metabolic processes but having temp in another body part be affected by external environment they are endo heterotherms.
66
In which ecto or endotherm is there a metabolic rate limit?
In endotherms as they use metabolism to regulate their internal temperature.
67
What is the thermal neutral zone
This is a zone in which endotherms metabolic rate stays stagnant across temperature, this is also where performance is best so it's the ideal range of temperatures.
68
What happens when you move outside of the thermal neutral zone for endotherms?
The organisms metabolic rate with increase or decrease in order to cool or warm the organism back to it's thermal neutral zone.
69
What are critical limits
in both ectoderms and endotherms, is temperature when performance is the worst and the organisms capacity to cool/warm has reached it's limit.
70
What is the performance optima and how do organisms get their?
is a temperature that ectotherms perform best at, get to this by changing behaviour (ie moving around so that they get to an environment with this temperature)
71
How do we generate thermal performance curves?
Through experiments
72
What are limits in thermal performance curves?
Is where performance is lowest and we see an imminent sign of death
73
What are dynamic limits?
When you use critical temperature as a measurement as thats when an organism can't regulate it's temp anymore and this is different among organisms
74
What are static thermal performance limits?
LT50- is the lethal temperature at which 50% of organisms in a habitat have died.
75
If an organism is at their lower critical limit, what does that mean?
This means that the organism is so cold it's lost the ability to warm up again and fill freeze to death soon. Performance is down due to slowed muscle contractions, slowed atp production, and decline in nervous function.
76
If an organism is at their upper critical limit what does that mean?
It means the organism is hot and it's lost it's ability to cool down will result in reduction in metabolic efficieny, cellular stress from heat shock, and the body turn to fermentive practices as the oxygen supply hits it's limit and still cannot meet the fast metabolic processes occuring in the organism.
77
In a thermal performance curve, is the optimal ambient temperature range narrower for an ectotherm than an endotherm? why?
yes, this is because ectotherms can't maintain their own internal temperatures so they are more sensitive to environmental temperatures- can't live in the hotter temps a endotherm can.
78
Place L05 Q here
plz
79
What does behavioural ecology focus on?
behavioural ecology focuses on individual behaviours and how they impact fitness and interaction with the environment.
80
What is optimal foraging theory based on and what does it assume?
Optimal foraging theory is based on the idea that natural selection will influence how organisms eat and forage, it assumes that organisms that are more effective at feeding will be favoured by natural selection. These strategies however have to have a genetic component (ie behaviour is genetic)
81
What two optimal foraging models are there?
the patch model and the optimal diet composition model.
82
How would a graph of energy gain vs time look if an organism is foraging in a single patch?
It would increase linearly but then eventually plateau as the patch runs of out food but we keep searching.
83
Say you spent time travelling to get to a patch, should you spend more or less time foraging than if you did not search for the patch?
more as we just lost energy trying to find the patch so we must stay longer in the patch to recuperate that energy lost, graphically we want the highest slope for energy gain, and the optimal time (when the two lines meet) is large at this slope.
84
How does the quality of a patch influence the time time spent in it?
in a low quality patch, the rate of gain will start slow, the overall slope will be lower (so a lower optimal energy) and you will also spend less time in a low quality patch versus a higher one. It will also plateau faster.
85
What are the three predictions made from the patch model?
That foragers should abandon a patch when the rate of energy gain is at a maximum, that they should stay in a rich patch longer than a poor patch, and that they should spend more time foraging if they spent more time searching (when foraging patches of the same quality)
86
What are three factors to consider in the optimal diet model?
Handling time, search time, energy intake
87
What makes up the forager time (denoted T)
The search time (Ts) and the handling time (Th)
88
How can you calculate profitability of a food item that's in front of you?
Take the energy value (Ei) of the food and divide it by the handling time.
89
Say you have a food item in front of you, and another food item a ways away, which food item should you eat?
take Energy of Prey 1/handling time, and then prey aways away take energy/handling time + search time)
if the second value is large go search for the far away item (be a specilaist), if it's not larger than just eat item in front of you (generalist)
90
What is a specialist and what is a generalist?
A generalist is an organism that does not eat it's most high E prey because it's rare so they just eat food with shorter search times.
A specialist is an organism that only eats it;s high E prey because it's common w low search time
91
Organisms only include a food source in their diet if?
if their rate of energy intake increases by doing so
92
l07- What is a functional response?
A functional response describes the relationship between the rate of feeding of an individual predator and the densit y of the prey item
93
What is a type 1 functional response?
As prey density goes up, rate of feeding (prey eaten by predator over time) goes up as well linearly
94
Say the slope of the feeding type 1 graph was steeper what does that mean? Say it was lower?
If the slope was steeper, that means that with increasing density a higher rate of prey is eaten over time, if lower it'd be a lower amount of prey overtime. This could be indicative of how efficient the predator is at catching prey.
95
How do you calculate the feeding rate if given the slope of a type 1 graph?
You would just isolate for y as x is prey density and slope is the rate of feeding over time per prey density.
96
What kind of organism is expected to have a type 1 functional response?
Organisms with no handling time as they can keep on eating prey as it increases, for ex filter feeders
97
What is a type two functional response?
Is where we start off linear with the feeding rate (prey eaten by predator over time) increasing linearly compared to the prey density but once it reaches a certain prey density the graph plateaus.
98
What causes the plateau is a type two functional response graph?
This is caused by predator becoming overwhelmed by prey, there's too much prey and the predator cannot eat the prey any faster so they have to start eating at their own max rate.
99
What type of organisms have a type two functional response?
Most, for example us.
100
What happens during a type 3 functional response?
At a low prey density the feeding rate increases slowly, then towards the middle it increases near linearly, and then it tapers off towards end
101
Why does the type three functional response look like that?
Because the predator could be bad at hunting initially and then begin to get better as more prey emerge and then reach it's max feeding rate when prey density becomes high, could also be that the predator chooses to eat more easily accessible prey or can't find prey when the density is low, and then begins to find or switch to this prey food source as density increases.
102
Describe what ideal free distribution is
States that the number of individuals that will aggregate in various patches is proportional to the amount of resources in the patch, so each organism should have an equal amount of prey.
103
What does ideal free distribution assume?
It assumes that individuals can accurately judge the quality of different habitats and are free to move between patches.
104
L08- What is sexual selection?
selection that depends on the advantage individuals have in reproduction over others of the same sex and species
105
What does sexual selection get affected by?
Involves anything that increases an individuals ability to reproduce
106
What are sources of fitness differences in sexual selection?
Survival differences, gamete production, mating ability, and fertilizing ability
107
What secondary sexual characteristics?
Characteristics of males and females not directly involved in the process of reproduction. Ex: colorful feathers
108
Define intrasexual selection
When same sex individuals compete among themselves for mates
109
Define intersexual selection
When individuals pick mates of the opposite sex based on a particular trait.
110
Why is there intrasexual selection, as in why is there competition between same sex's?
Because members in the same sex are competing bcuz they want an opportunity to mate or fertilize gametes. an example of this competition is fighting
111
Why is there intersexual selection?
Because individuals choose mates of the opposite sex based on secondary sexual characteristics like songs, or bright feathers.
112
Why would an organism pick a mate of the opposite sex based on secondary sexual characteristics?
Because it makes them appear fitter as they have excess energy to put into these traits and shows good genes.
113
Which sex has a higher reproductive investment? Males or females?
Females because they produce larger gametes than males (put more energy into there gametes)
114
Why do males show much more variation then females in terms of reproductive success?
Because females have a higher reproductive investment they're only limited by availability of resources for making their gametes and offspring, however males have a lower reproductive investment so they're limited by finding a mate which is the females choice and is highly variable.
115
What strategy should females take when choosing a mate?
They should be very picky because they have a put a very high investment of energy in their gametes so they want the best possible mate to get the best outcome off offspring. They are picky by looking at secondary sexual characteristics.
116
What type of sexual selection applies to females?
intersexual as females choosing mates
117
What reproductive strategy should males take ?
Since they're opportunities to mate are very variable at mating is a low investment for them they should mate with anyone they can.
118
What type of sexual selection is important for males?
intrasexual selection, competing with dudes and that's why they're so flashy.
119
Describe bateman's principle
In a population, females will always be less ready to mate compared to males as they have a high reproductive investment in gametes and parental care, this leads to competition between males, high variance in their reproductive success, and males have stronger selection for traits affecting their competitive ability, females become more choosy with partners, and this causes selection pressure from females in males for traits that will show they're fit (secondary sexual characteristics)
120
What are some exceptions to batemans principal?
Females can be promiscuous- they can have more then one male, this allows them to increase chances of genetic compatibility as they can choose from a variety of sperm, avoid inbreeding, and avoid infanticide (lions will kill lionesses babies so they mate w them so the lion thinks the cubs are it's own).
Males can be choosey- Sperm is not always cheap sometimes males can get eaten by females after copulation so they're more hesitant and sometimes males are the primary care giver from offspring (ex: male seahorses)
121
L09 What are some life history traits? Describe them
size at birth- bigger offspring better at survival
rate and pattern of growth- is they can grow early makes them less vulnerable and maximizes their survival
Age at sexual maturity- if they reproduce faster that allows you to be more fit
Size at sexual maturity- If you're bigger at this point can create bigger offpsring
length of life- longer you live more offspring you give
Number, size, and sex of offspring- want big, want big number
Age and sex specific reproductive investment
Mortality schedules- does the pop live longer or die early- this affects survival of organisms
122
What are life history traits?
Biological traits that influence the schedule of survival or reproduction, happens on an individual scale
123
What is the principle of allocation?
An organism has a set amount of energy, if you give a lot of energy to one life history trait a decrease of equal proportion will occur in another one
124
Do organism consciously follow the principle of allocation and budget their energy?
No, this is driven by natural selection
125
Is the energy an organism gives to one trait static- as in the same over their whole life?
No, it can change - for example at sexual maturity an organism might put more energy into reproduction but then later on in life can then put more energy in activity.
126
In the principle of allocation what is denoted u?
This is our organisms energy amount used from the surplus energy
127
In the principle of allocation what is surplus energy and how is it denoted?
Surplus energy is energy left over from metabolism and respiration and is denoted as 1
128
Say you used u amount of energy towards growth, how much energy do you have left for reproduction?
1-u
129
What is optimum allocation for growth (u*)
Is the amount of energy (u) that is needed to reach the highest fitness and leave energy for reproduction purposes as well.
130
Say U=1, for allocation growth, then what's fitness?
Well calc left over energy you have for reproduction, 1-u, so 1-1= 0, no energy left for reproduction so bad fitness.
131
How do we achieve the greatest fitness with the energy we have in terms of the principle of allocation?
We balance costs and benefits of pushing energy to reproduction versus growth (through life history traits) in order to find optimal allocations for each trait.
132
What are the currencies for life history traits?
How fast the number of individuals of that genotype increase over time (so the growth rate of a genotype)
AND
reproductive value (the number of descendants a female has in their whole life)
133
How do we denote the growth rate of a genotype?
it is denoted as r
134
How do we denote the reproductive value?
it is denoted as R0
135
What life history strategy will natural selection favor?
It will favour the strategy with the highest total reproductive value and growth rate of a genotype (ie intrinsic rate of increase)
136
Where is there tradeoffs in life history traits coming from? Why is there tradeoff why can't all traits be equal and present?
Organism has a finite amnt of energy, so all life history traits are dependant on each other in terms of how much energy we spend on them
137
What are the two major trade off types?
Allocation of reproductive effort- Should the organism produce a few big offspring or a lot of small little ones?
Production effort (GROWTH VS REPRODUCTION)- Should the organism reproduce young or old? How often should it reproduce?
138
In the allocation of reproductive effort, what is the trade off (Number v size) if the organism produces big children, how about small?
If the organism produces big children, there will be less of them produced at a time- however the organisms with have a higher probability of survival
If the organism produces small children they might produce a lot, but since resources will be further divided among offspring survival might be less.
139
What must one consider when deciding between allocating more energy to number vs size
The environment they're in, for ex if a lot of predation might be more favourable to make few large offspring to ensure chance of survival
140
What are the costs of reproducing for an organism (size v number costs)?
The current costs are that reproduction uses energy and other reserves, but future costs might be that you won't be able to reproduce next year, and you might have less of a survival rate (if producing a large brood size (many babies)
141
Say an organism reproductivity is very low, is growth rate high or low?
growth rate is high.
142
Why do organism with a high adult mortality age usually mature earlier?
Because since they don't long they need to reproduce while alive, also it increases their probability of survival because they are minimizing the stage in life when they are juveniles.
143
What are the benefits of maturing later and at a larger size?
You'll have bigger offspring, lower adult mortality cause you're bigger and higher quality offspring which increases their probability for survival.
144
L10
not finished yet do later
145
L11 What is game theory?
A branch of mathematics devoted to the study of strategy where players seek to maximize their individual returns (resource cards)
146
In the aggressive method when it comes to competition for resources what happens if a hawk vs a hawk (two aggressive animals) face off? What happens if the hawk loses?
The hawks will always fight each other for the resource, but if it loses it will suffer an injury cost (denoted as C) and lose the resource.
147
What happens if a non agressive animal goes up against a non agressive animal? What happens if it loses the resource?
The animals will not fight but will put on a show, the one that puts up a bigger fake show will win. If the dove loses it'll just lose resource, no injury cost cause it didn't fight
148
Can a single dove invade a population of hawks?
No because the non agressive animal will always lose the resource when facing an agressive animal.
149
What is an evolutionary stable strategy?
a behavioural strategy that is resistant to invasion, and most likely to be maintained by natural selection
150
Can a hawk invade a population of doves?
Yes as it always win the resource as it's agressive
151
What is frequency dependent selection?
When an individuals fitness depends on the relative frequency of other phenotypes in the population.
152
What is positive frequency dependent selection?
Is when the majority phenotype in the population has an advantage.
153
What is negative frequency dependent selection?
When the minority phenotype has an advantage.
154
Can a frequency exist where all phenotypes have the same fitness?
Yes
155
Look at graph on slide 20 and explain all trends and patterns including what a stable state is.
156
L-12 Define population ecology
the study of the spatial and temporal patterns in the abundance and distribution of organisms and the mechanisms that produce those patterns
157
What is stochasticity in a graph?
Is when the general trend is the same but there's little variation in it
158
Why would a population say of sheep begin to plateau?
Because resources become limited
159
Describe the two different patterns of growth on slide 7 and why they are different
The second plot has a lot more variation where the population dips and then starts again this is because the hotter temp in the popln lets them metabolize faster however this causes them to use their resources faster as well until eventually there's no more and the popln crashes until the resources accumulate again and then the popln starts back up.
160
What are the two processes that causes population size to change?
Vital rates (so the births and deaths of a popln)
Movement (so the immigration and emigration in a popln)
161
What does N refer to in a popln?
N is the population size
162
What does Nt notate?
The popln size at time T
163
What does Nt+1 notate?
Population size at one time step ahead of Nt
164
How is population size at a time in the future mathematically expressed?
It Nt= Population at original time+Birth rate (B) - death rate (D) + immigration (I) - emigration (E)
165
How is the change in a popln expressed mathematically?
Delta N= B-D+I-E
166
What is a closed population?
A population that is spatially isolated so only birth rate and death rate effect a change in population size.
167
What is a open population?
Is a population that has birth rates and death rates, but also has movement so immigration and emigration is involved.
168
What is a meta population?
This is a network of distinct populations that are all open so the immigrate and emigrate between each other.
169
What are total rates?
These describe the rate for the total population, are denoted by capital letters, and are births over time for ex.
170
What are per capita rates?
These describe rate (such as birth) for each individual over time, they're denoted by lower case letters such as b
171
In a closed population what is the change in population with respect to time?
dN/dT= bN-dN as bN equals population change over time and dN equals population change over time, so we take the difference of both which will be popln change over time which equals to dN/dT. If we make the time approach 0 this tells us the instantaneous rate of change in the population.
172
What is r?
r denotes the per capita rate of increase as it equals r= b-d, r multiplied by population size (N) tells us the instantaneous rate of change in the population.
173
If r is negative what does that mean for the birth rate per capita? The death rate per capita? The over all population size?
If r is negative that means the death rate per capita is higher than the birth rate per capita, so the overall population size is decreasing.
174
What is density independent growth?
Is when the population density has no effect on the per capita birth and death rates
175
If r>0 what will the population growth over time look like?
exponential as it's continuously increasing.
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If r<0, what will the population growth over time look like?
Will be exponential decrease as per capita death rate higher than birth rate.
177
If r=0, what will a population over time graph look like?
Stagnant, as birth and death rate are equal so pop size will stay the same.
178
In a density independent growth does r get affected by popln density? Does the total rate of change of the population get affected by popln density?
No r does not get affects as r equals (b-d) and per capita rates stay the same in a density independent model, however the total rate of change of the popln still gets affected as dn/dt= r *N so as popln size increases dn/dt will increase as well.
179
What is rmax?
this is the instrinsic rate of increase it happens under ideal conditions in which the birth rate is maximized and the death rate is minimized
180
Under ideal conditions how do we find the rate of change in a population?
dN/dt= rmax * N
181
How do we find the population density of our population when we are under ideal equation?
Since under ideal equations we have exponential growth, Nt=Noe^rmax*t
182
What is discrete growth, what is continuous growth?
discrete growth is when populations over time are increasing but they have stagnant periods and are not increasing continuously, this can be do to having certain reproductive times. Continuous growth is when a population grows all the time.
183
What is the discrete difference equation?
Is the equation used to calculate a population at a time when the growth of it is discrete. Is Nt= lambda^t*N0
184
What us lambda in the discrete difference eqn?
Lambda is the finite/geometric rate of increase and equals 1 + (b-d).
185
If population is decreasing, what is lambda?
Lambda is less than 1
186
If population is increasing what is lambda?
Lambda greater than 1
187
If popln is stagnant, what is lambda?
Is 1
188
What does lambda measure?
The ratios between the population at a time and then at a future time.
189
Lec #13 What is density dependent growth?
Is when the per capita birth and death rates are affected by the popln density
190
What happens to the birth rate as density of a pop increases in density dependent growth?
Will decrease as they're will be less resources when population is denser so organism will put energy into finding resources rather than reproducing.
191
What happens to the death rate per capita as density of a population grows?
Will increase as there's less resources.
192
What is K in the density dependent growth model?
K equals a stable equilibrium and popln density in which the per capita birth and death rate are equal
193
What happens when the population density (N) is above K?
The population will begin to die off as theres less resources for everyone, returns it back to K.
194
What happens if the popln density is below K?
the popln will increase as there's still resources so death rate per capita is smaller compared to birth rate per capita
195
What is the equation for per capita birth rate in density dependent growth?
b= b0(birth rate when popln 0) -aN
a= slope of line in birth rate vs density graph, as density increases birth rate decreases due to competition so negative slope.
196
What is the equation for per capita death rate in density dependent growth?
d= d0 + CN
d0- is per capita death rate when popln 0
C= is slope of line in per capita death rate vs densty graph
As popln increases, death rate increases due to competition so positive slope.
197
What is the eqn for density dependent growth (ie the logistic growth eqn)?
dN/dt= rmax[1-N/k]N
198
When N=k, what is dn/dt? What is r?
When N=k, carrying capacity has been reached so birth and death rate are equal and r =0, since there's an equal change in birth and death, the popln size is stagnant so change in the popln at this time (dn/dt) is also 0.
199
What sre some reasons per capita death rates get so heavily affected by high poplns?
competiton, and now easy for predators, and diseases travel easy.
200
Say you plot r vs density, what slope will r over pop density have, where will r be the highest (rmax) where will r be the lowest? What point is r the lowest at?
Since death rate increases with popln density, r will decrease over increasing popln, causing a negative slope. When r=0, this popln density will equal K (the carrying capacity) as at this point b=d.
201
Describe the Allee effect
This is when instead of the normal density dependent model, the per capita growth rate begins low at low population densities, then increases at low (but higher then before) population densities, and then decreases once again and follows the density dependent pattern at high popln densities. This can be because at low popln densities some species can't find mates or they need more of them to fight off predators, then when they increase a bit they find mates and then we resources become sparse as density increases the growth rate goes low again.
202
lec #14 What are three ways populations can have structures?
Through age, stage of life (because it effects vital rates), and sex
203
How does structure effect a population?
It impacts N (pop density) and dN/dt.
204
What do we need to know in order to determine the effect of structure on a population?
Need to know the structure present and need to know how that structure impacts vital rates.
205
Define demography
The branch of population biology dealing with population projections for age structured populations
206
How does age effect a population? Why would we want to know how age effects it?
Can effect it with survivorship, at different ages survival can be lower or higher.
Can effect it with reproduction- different age classes can reproduce more or less
This all effects pop density and change in pop over time.
207
What is survivorship?
The pattern of survival for individuals in a population as a function of age
208
How do you find survivorship?
You calculate it from cohort tables, so look at number of individuals in an age class that survived to a certain age.
209
What is the difference between a cohort table and a static life table? Are they both just referred to as cohort tables?
A cohort table looks at one cohort throughout its life, a static table looks at one cohort and assumes that the survivorship stays the same so uses data at one time to predict future data.
210
When creating a survivorship graph, what scale do we plot the number of survivors in?
In logarithmic scale
211
In a life table how de predict the number of survivors in year 2, given data of survivors and death in year 1?
Subtract deaths for survivors in year 1, that will be the survivors in year 2.
212
How many types of survivorship curves are there?
Three
213
What happens in a type 1 survivorship curve?
Here young survive but old die.
214
What happens in a type two survivorship curve?
Everyone dies at an equal rate regardless of age
215
What happens in a type three survivorship curve?
Individuals die at a high rate as young but die less when old.
216
In what species do we see type 1 curves?
K selected species
217
What is a k selected specie?
Is a specie that puts a lot energy in a single offspring, produce a few really good offspring so they're can survive early on but later mortality kicks in as they invested so much energy into reproducing and parental care they become weak when old.
218
In what species do we see type two survivorship curves?
This is in populations that have constant predators and disease, so mortality is present in all age groups equally. Also see this in organism that don't really grow much- for ex sparrows.
219
In what species do we see type three survivorship curves?
See this in r selected species, these produce a lot of offspring and don't devote much energy to each, so a lot die young but if they make it mortality rate decreases because they didn't spend much energy in reproduction.
220
Define fecundity
The average number of offspring produced by a female in each age class
221
Define semelparity
Organisms only reproduce at one age class
222
Define iteroparity
organisms reproduce in multilple times in lifespan.
223
What are life tables?
Tables that combine the survivorship and fecundity schedules and are used to estimate the net reproductive rate
224
What is R0?
notates the net reproductive rate
225
How do we calculate R0?
Take proportion of individuals that survived in each age class (lx) and multiply it by the average number of offspring in each age class (mx). Then add all the values for each age to get R0.
226
If R0 is greater than 1 what happens to the population?
The population will increase over time
227
If R0 is less than one what will happen to the population?
The population will decrease over time.
228
If R0 is one what will happen to the population?
If R0 is one, the population will stay stagnant over time.
229
What is a stable age distribution?
When the proportion of individuals in each age class is constant over time.
230
What are stages (in terms of stage structured population)
Sometimes in a population a range of ages are the same in their vital rates so we group them all up into a stage
231
When is the age structure stable?
When the proportion of fecundity and survivorship in age classes is similar.
232
Lec #15 What is habitat fragmentation?
When developments to a land impact the local populations in them ie split them up.
233
Is habitat fragmentation always humans fault?
No for ex natural disasters like earthquakes can cause it too.
234
What is a subpopulation, what is a metapopulation?
Subpopulations are small populations that are spatially isolated by a matrix of bad land. A bunch of these subpopulation together are metapopulations IF there can be some sort of connection between them.
235
What are the four conditions that define metapopulations?
Suitable habitat is in discrete patches (separate land) that are occupied by breeding populations
Even the largest patch has a risk of extinction
Habitat patches are not too isolated to prevent recolonization (possibility of connectvitiy between poplns)
Population dynamics are not synchronized (means not all poplns go up and down at the same time, subpopplns dynamic in meta pop. I
236
What two different spacial scales are thy're in a metapopulation?
Local scale – within a patch
Regional scale – between patches (metapopulation)
237
What is colonization (in terms of metapopulations)
the movement of individuals from occupied sites to unoccupied sites to form a new local population
238
What is needed for a metapopulation?
Need a balance between the extinction of local populations and colonization of empty habitats.
239
Does scale matter when analyzing a metapopulation?
Yes the scale should match the biology of organisms your looking at, for ex if studying ants we won't set our scale to be kilometers.
240
What does P denote?
Is the fraction of patches occupied in a metapopulation and range from 0 to 1.
241
What does dP/dt denote?
It stands for change in the number of occupied patches over time, it equals the colonization rate (C) over the extinction rate (E).
242
Why might animals want to immigrate, emigrate?
Because there's less resources in their patch, because there's more predation or competition, or maybe because of environmental disturbances.
243
What two factors affect the rate of colonization?
Ability to move (can they travel distance between patches) and reasons to move
244
What factors affect extinction?
Diseases, resource availability, predation, disturbance (by humans), population size(is there enough mates for everyone)
245
What is the equation for the colonization rate?
Its the amount of occupied patches (P) times the rate of movment (m) times the amount of patches available to move into (1-P)
so C= mP(1-P)
246
What is the equation for the extinction rate?
P(fraction of patches occupied) times (e) extinction to find proprtion of patches going extinct over time.
247
Why in the graph of extinction and colonization vs occupied patches is extinction linear and colinzation curved?
This is because as the proportion of occupied patches increases extinction also increases as more competition for resources, however for colonization we start of low as there's no organisms occupying patches all are empty, as organism s start occupying patches then colonization goes up as now organism can actually move in between patches, but this eventually decreases because all the patches become full so there's no room to move around anymore.
248
Is the point at which E and C function intersect a stable state?
Yes as, if the proportion of occupied patches increase, more extinction happens and than patches open up so colonization can resume at high rates again.
249
Is the stable state dynamic or static (when it comes to colonization and extinction rates)?
Dynamic as if population are separated further colonization rate could go down and extinction rate could go down changing stable state point.
250
What are the assumption made in open metapopulation model
All patches are equal in quality
Rates of extinction and colonization for each patch are the same
Each occupied patch contributes equally to dispersal
Colonization and extinction in each patch occur independently of other patches
The colonization rate is proportional to the fraction of occupied patches
251
What assumption is violated in the open metapopulation model?
That all patches are equal in quality, patch quality matters and it is what causes source and sink populations.
252
What is a source population and what is a sink population?
A source population is a good quality patch and sink population is a bad quality patch.
253
What is the rescue effect?
High immigration rates protect a population from extinction due to frequent recolonization, so the source population saves the sink population through immigration.
254
What is the mainland island metapopulation structure?
A single patch is the biggest source of organisms migrating to other patches, ie a big forest and then two small patches next to it.
