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Community and Population Ecology > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

What is ecology?

A

The scientific study of the processes influencing the distribution and abundance of organisms, the interactions among organisms, and the interactions between organisms and the transformation and flux of energy and matter.

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2
Q

What are the four fundamental factors that influence the growth rates of populations?

A

Immigration, emigration, birth rates, and mortality rates

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3
Q

We can describe population growth using…?

A

Mathematical tools of differential calculus (continuous time) and difference equations (discrete time).

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4
Q

Are there limits to population growth rates?

A

Yes, these limits are often, but not always, are due to limited resources.

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5
Q

Limits on population growth can also occur when the population is at what size?

A

When the population is small.

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6
Q

Geometric growth

A

Happens over discrete time intervals
ex: t = 1, 2, 3 etc.

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7
Q

Exponential growth

A

Happens over continuous time
ex: every number between 1 and 2 and 3 and etc.

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8
Q

Do exponential and geometric growth describe the same things?

A

Yes, just over different time intervals.

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9
Q

When the population is closed, what does that mean?

A

I = E = 0

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10
Q

In logistic growth, population growth rate is maximal when?

A

At an intermediate population size.

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11
Q

In logistic growth, the Per-Capita Growth is?

A

A linear decreasing function of N.

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12
Q

Carrying capacity is determined by?

A

Both the amount of resources and conditions of the environment.

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13
Q

What are the four discrete time models that have negative density-dependence?

A

Discrete logistic equation
Beverton-Holt stock-recruitment Model
Hassell Model
Ricker Model

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14
Q

Allee effects

A

Positive density-dependence at low densities.
-Mate limitation
-Cooperative defense
-Cooperative feeding

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15
Q

Individuals of different ages or stages have different ______ and ______ rates and so influence population growth in different ways.

A

birth and death

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16
Q

Life tables allow…?

A

The calculation of many different types of population dynamic quantities, including the generation time, stable age structure, reproductive values, and population growth over a generation.

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17
Q

Calculating the geometric growth rate in age or stage-structured populations can be done via ______ or using methods in _________.

A

“Brute Force” ;
linear algebra

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18
Q

Real populations are best though of as?

A

Populations of populations – metapopulations with movement between patches.

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19
Q

The spatial structuring of metapopulations tends to reduce?

A

The risk of extinction

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20
Q

In metapopulations, local populations are going extinct and are being colonized often. What does this lead to?

A

This leads to turnover in the occupancy of the patch.

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21
Q

What is metapopulation theory used extensively in?

A

Designing wildlife and conservation reserves.

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22
Q

____________ is a very important thread through much ecological research.

A

Stability of ecological systems

23
Q

We like to think that things are stable because stability have _________.

A

overtones of a “balance of nature.”

24
Q

What can stability be studied with?

A

Models

25
Q

The predictions from the stability models can be tested using?

A

Observational and experiments.

26
Q

What is stability?

A

Is the general property or returning to a state, or set of states, if perturbed away from that state.
These states are equilibria of a system.

27
Q

Why are equilibria useful to know?

A

Because they are good candidates for where the system (i.e. a population, community, ecosystem) may end up if the equilibrium is stable or move away from if it is unstable.

28
Q

What are the basic types of equilibria?

A

Stable, unstable, and neutral equilibrium.

29
Q

The major life history traits are all involved in _____ that cause them to come to an…?

A

Tradeoffs;
an evolutionary equilibrium at intermediate, not extreme, values.

30
Q

What are some factors that are all subject to natural selection and have evolved to solve particular ecological problems.

A

Age and size at maturity, number and size of offspring, and life span are all subject to natural selection and have evolved to solve particular ecological problems.

31
Q

Their evolution can be understood as an interaction between ______ ecological conditions that determine ________ rates and conditions inside the organism that cause _______ among traits.

A

extrinsic ; mortality ; tradeoffs

32
Q

What are extrinsic factors?

A

Are external to the organism and include the ecology of the organism.

33
Q

What are intrinsic factors?

A

Are internal to the organism. Genetic and energetic trade-offs. Rate of energy metabolism. Genetic architecture.

34
Q

The strength of selection is strongest at what ages?

A

Is strongest at young ages and then declines with increasing age.

35
Q

Changes early in life will result in?

A

Changes early in life will result in large increases in fitness, while those at older ages have a smaller effect on fitness. w

36
Q

What are the benefits of earlier and later maturation?

A

Earlier maturation:
1) Shorter generations
2) Higher survival to maturity because of shorter juvenile period
Later maturation:
1) Higher initial and later fecundity through longer growth
2) Lower instantaneous death rates of offspring.

37
Q

The life history of an organism is marked by major transitions including:

A

Birth, maturation, and death.

38
Q

When events in life occur, costs and benefits toward fitness.
These costs and benefits are shaped by:

A

extrinsic (ecological) and intrinsic (trade-offs, genetic correlations, etc) factors.

39
Q

The set of life history decisions that is predicted to evolve is:

A

a balance between the costs and the benefits that maximizes relative fitness.

40
Q

What happens when the environment is variable? Reaction norms for age and size at maturity.

A

Rule 1: Always mature at the same size
Cost: Mortality
Rule 2: Always mature at the same age
Cost: loss of fecundity
Rule 3: Compromise = Reaction Norm

41
Q

The evolution of reproduction lifespan depends on ?

A

The balance between juvenile and adult survival

42
Q

The evolutionary explanation to the question “Why do we age?” has three parts:

A

1) The force of selection declines with age such that older organisms becoming increasingly more irrelevant to evolution.
2) Clear separation between germ line and somatic line.
3) Under these conditions, two sorts of genetic effects become possible: Mutation accumulation and antagonistic pleiotropy.

43
Q

What is mutation accumulation?

A

The accumulation of more mutations with effects on older age classes than on younger ones.

44
Q

What is antagonistic pleiotropy?

A

The accumulation of antagonistically pleiotropic genes that benefit younger age classes at the expense of older ones.

45
Q

______ and _____ at older ages makes little difference to fitness.

A

Birth and death

46
Q

What is Muller’s Ratchet?

A

Gradual buildup of mildly deleterious mutations in the population.

47
Q

Population sizes can be estimated using?

A

A variety of capture-mark-recapture methods.

48
Q

Marking individuals instead of simply marking caught individuals yields…?

A

Better unbiased estimates of population size.

49
Q

When individuals can die between capture events, the probability of capturing an individual the next time is called?

A

Return rate

50
Q

The methods of mark recapture methods allow us to test?

A

Ecological hypotheses

51
Q

Most populations show some degree of _______ (______) in their population sizes.

A

Randomness (stochasticity)

52
Q

Stochasticity arise due to?

A

Environmental variation across time periods, random differences among individuals within a time step, random differences coupled with small population sizes, and measurement error.

53
Q

The growth rate of stochastic populations is always less than the…?

A

Mean geometric rate of increase, which has big consequences for population viability.

54
Q

Random differences between individuals can be calculated using?

A

Individual data over many time steps.

Community and Population Ecology (1 decks)

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