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Biology II - Exam 4 > Chapter 53 > Flashcards

Chapter 53 Flashcards

1
Q

Population Ecology

A

Explores how biotic and abiotic factors influence density, distribution, size, and age structure of populations

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2
Q

The number of loggerhead turtle hatchlings that survive their first journey to the ocean is affected by both _ and _ factors.

A

Biotic; abiotic

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3
Q

Population

A

A group of individuals of a single species living in the same general area

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4
Q

Populations are described by their _ and _.

A

Boundaries; size

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5
Q

Density

A

The number of individuals per unit area or volume

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6
Q

Dispersion

A

The pattern of spacing among individuals within the boundaries of the population

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7
Q

In most cases, it is _ to count all individuals in a population.

A

Impractical (or impossible)

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8
Q

_ can be used to estimate densities and total population sizes.

A

Sampling techniques

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9
Q

Population size can be estimated by either extrapolation from small samples, and index of population size (e.g., number of nests), or the _ method.

A

Mark-recapture

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10
Q

Determining population size using the mark-recapture method:

A
  • Scientists capture, tag, and release a random sample of individuals (s) in a population
  • Marked individuals are given time to mix back into the population
  • Scientists capture a second sample of individuals (n), and note how many of them are marked (x)
  • Population size (N) is estimated by N = (sn)/x
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11
Q

_ is the result of an interplay between processes that add individuals to a population and those that remove individuals.

A

Density

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12
Q

Immigration

A

The influx of new individuals from other areas (in)

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13
Q

Emigration

A

The movement of individuals out of a population (out)

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14
Q

Three patterns of dispersion:

A
  • In a clumped dispersion, individuals aggregate in patches
  • A uniform dispersion is one in which individuals are evenly distributed
  • In a random dispersion, the position of each individual is independent of other individuals
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15
Q

Demography

A

The study of the vital statistics of a population and how they change over time (birth and death rates)

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16
Q

_ and _ are of particular interest to demographers.

A

Death rates; birth rates

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17
Q

Life Table

A

An age-specific summary of the survival pattern of a population

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18
Q

A life table best made by following the fate of a _, a group of individuals of the same age.

A

Cohort

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19
Q

Survivorship Curve

A

A graphic way of representing the data in a life table

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20
Q

Survivorship curves can be classified into three general types:

A
  • Type I: Low death rates during early and middle life and an increase in death rates among older age groups (ex: humans and other high-level eukaryotes)
  • Type II: A constant death rate over the organism’s life span (under constant threat of predation)
  • Type III: High death rates for the young and a lower death rate for survivors (ex: sea turtles)
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21
Q

Many species are _ to the three types of survivorship curves.

A

Intermediate

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22
Q

The exponential model describes population growth in an idealized, _ environment.

A

Unlimited

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23
Q

The exponential model is useful to study population growth in an _ situation.

A

Idealized

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24
Q

Idealized situations help us understand the _ of species to increase and the conditions that may facilitate this growth.

A

Capacity

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25
Change in population size =
Births + immigrants entering population - deaths - emigrants leaving population
26
If immigration and emigration are ignored, a population's growth rate (r) equals _ minus _.
Birth rate; death rate
27
_ growth occurs when the birth rate equals the death rate.
Zero population
28
_ population growth is population increase under idealized conditions. Under these conditions, the rate of increase is at its maximum, denoted as _.
Exponential; rmax
29
The J-shaped curve of exponential growth characterizes some _ populations.
Rebounding
30
The elephant population in Kruger National Park, South Africa, grew _ after hunting was banned.
Exponentially
31
Exponential growth cannot be _ for long in any population.
Sustained
32
A more realistic population model limits growth by incorporating _.
Carrying capacity
33
Carrying Capacity (K)
The maximum population size the environment can support
34
The Logistic Model
Describes how a population grows more slowly as it nears its carrying capacity ("logical")
35
In the logistic population growth model, the per capita rate of increase _ as carrying capacity is reached.
Declines
36
When population size equals the carrying capacity (K), the population _ growing.
Stops
37
The population growth rate _ as population size approaches K.
Decreases
38
The growth of laboratory populations of paramecia fits an _ (logistic model) curve. These organisms are grown in a constant environment lacking predators and competitors.
S-shaped
39
An organism's _ comprises the traits that affect its schedule of reproduction and survival.
Life history
40
Life history traits are evolutionary outcomes reflected in the _ of an organism.
Development, physiology, and behavior
41
A life history entails three main variables:
- The age at which reproduction begins - How often the organism reproduces - How many offspring are produced per reproductive episode
42
Organisms have finite resources, which may lead to trade-offs between _ and reproduction.
Survival
43
There is a trade-off between survival and _ in European kestrels.
Paternal care
44
Some plants produce a _ number of small seeds, ensuring that at least some of them will grow and eventually reproduce.
Large
45
_, or density-dependent selection, selects for life history traits that are sensitive to population density (ex: predation, resources).
K-selection
46
_, or density-independent selection, selects for life history traits that maximize reproduction (ex: water availability, climate).
r-selection
47
In _ populations, birth rate and death rate do not change with population density.
Density-independent
48
In _ populations, birth rates fall and death rates rise with population density.
Density-dependent
49
Density-dependent birth and death rates are an example of _ that regulates population growth.
Negative feedback
50
Density-dependent birth and death rates are affected by many factors, such as:
-Competition for resources -Territoriality -Disease -Predation -Toxic wastes (not not affect density-independent populations)
51
Population Dynamics
Study that focuses on the complex interactions between biotic and abiotic factors that cause variation in population size
52
Long-term population studies have challenged the hypothesis that populations of _ are relatively stable over time.
Large mammals
53
Both weather and predator population can affect _ size over time.
Population
54
The moose population on Isle Royale _ during a harsh winter, and then wolf numbers _.
Collapsed; peaked
55
When a population becomes crowded and resource competition increases, _ often increases.
Emigration
56
Metapopulations
Groups of populations linked by immigration and emigration
57
Local populations in a metapopulation occupy patches of _ habitat surrounded by _ habitat.
Suitable; unsuitable
58
Local populations lost through extinctions can be recolonized by _ from other patches.
Immigration
59
The human population is no longer growing exponentially but is still _ rapidly.
Increasing
60
No population can grow _, and humans are no exception.
Indefinitely
61
The human population increased relatively slowly until about _ and then began to grow exponentially.
1650
62
The global (human) population is now more than _ billion people.
7
63
One important demographic factor in present and future growth trends is a country's _.
Age structure
64
Age Structure
The relative number of individuals at each age
65
How many humans can the biosphere support? Population ecologists predict a global population of _ billion people in 2050.
8.1-10.6
66
The carrying capacity of Earth for humans is _.
Uncertain
67
Scientists have based estimates on _ growth models, area of habitable land, and food availability.
Logistic
68
The _ concept summarizes the aggregate land and water area needed to sustain the people of a nation.
Ecological footprint
69
The ecological footprint is one measure of how close we are to the _ of Earth.
Carrying capacity
70
Countries vary greatly in _ size and available ecological capacity.
Footprint

Biology II - Exam 4 (4 decks)

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