Copy of Ecology of Individuals and Populations

Question 1

What are source–sink metapopulations?

Answer 1

Metapopulations that occupy a larger area, including marginal areas, due to continual influx of immigrants

They prevent long-term extinction by continuous colonization of empty patches.

Question 2

What is the Allee effect?

Answer 2

A phenomenon where growth rates increase with population size, often due to difficulties in finding mates or other factors

It is an example of positive feedback.

Question 3

What are density-dependent effects?

Answer 3

Effects on reproduction and survival that are influenced by population size

They can lead to decreased birth rates or increased mortality rates as population size increases.

Question 4

What are density-independent effects?

Answer 4

Factors that affect populations regardless of size, such as environmental disruptions and catastrophes

Examples include cold winters, droughts, storms, or volcanic eruptions.

Question 5

What is the typical cycle observed in North American snowshoe hare populations?

Answer 5

A 10-year cycle where population numbers can fall 10-fold to 30-fold

This cycle is influenced by food plants and predators.

Question 6

What role do food plants play in hare population cycles?

Answer 6

Food plants like willow and birch twigs decrease as hare density increases, leading to lower birthrates and juvenile survivorship

This results in a decline in hare abundance.

Question 7

What are K-selected life history traits?

Answer 7

Traits such as small brood size, late reproduction, and high parental care

These traits evolved under resource constraints during early human history.

Question 8

How has human population growth changed over time?

Answer 8

Human population has grown exponentially in the last 300 years due to technological advances

Birth rates have remained stable while death rates have significantly decreased.

Question 9

What is a population pyramid?

Answer 9

A bar graph displaying the numbers of people in each age category, with males on the left and females on the right

It helps assess future population growth trends.

Question 10

What are r-selected life history traits?

Answer 10

Traits that favor high reproductive rates in abundant resource environments

Examples include dandelions, aphids, and mice.

Question 11

What does the logistic growth model illustrate?

Answer 11

Population growth that stabilizes around the carrying capacity

It describes how populations tend to return to the same size over time.

Question 12

What information does a life table provide?

Answer 12

Probability of survival and reproduction through a cohort’s life span

It helps analyze population growth and dynamics.

Question 13

What is a survivorship curve?

Answer 13

A graph that shows how the survival probability of a population changes with age

Types include type I, type II, and type III survivorship curves.

Question 14

What type of survivorship curve is characterized by a high mortality rate early in life, followed by low mortality rates for survivors?

Answer 14

Type III survivorship curve

This curve is typical for species that produce many offspring, such as oysters.

Question 15

Which survivorship curve indicates that individuals are equally likely to die at any age?

Answer 15

Type II survivorship curve

This curve is exemplified by hydra, which are related to jellyfish.

Question 16

What is the characteristic pattern of mortality rates in humans as they age?

Answer 16

Type I survivorship curve

This curve shows steep increases in mortality rates later in life.

Question 17

What is a life table used for in ecology?

Answer 17

To show the probability of survival and reproduction through a cohort’s life span

It tracks the fate of a cohort from birth until death.

Question 18

What factors define a population’s age structure?

Answer 18

Cohort size, birth rate (fecundity), and death rate (mortality)

The age structure influences a population’s growth rate.

Question 19

How does a population with a large proportion of young individuals typically behave?

Answer 19

It tends to grow rapidly

This is because more individuals are in reproductive age.

Question 20

What is demography?

Answer 20

The quantitative study of populations

It examines how population size changes over time.

Question 21

What is the relationship between sex ratio and population growth rates?

Answer 21

The number of births is usually directly related to the number of females

Males may not significantly affect birth rates in species with competitive mating.

Question 22

What is generation time?

Answer 22

The average interval between the birth of an individual and the birth of its offspring

It can influence the growth rate of a population.

Question 23

What is biotic potential?

Answer 23

The maximum rate at which a population can increase when no limits are placed on growth

It is often represented mathematically in population growth models.

Question 24

What is carrying capacity (K)?

Answer 24

The maximum number of individuals that the environment can support

It limits population growth.

Question 25

What does the logistic growth model describe?

Answer 25

Population growth that slows as it approaches carrying capacity ## Footnote It incorporates environmental limitations.

Question 26

What is semelparity?

Answer 26

A life history adaptation where organisms reproduce once and then die ## Footnote It is often found in short-lived species.

Question 27

What is iteroparity?

Answer 27

A life history adaptation where organisms reproduce multiple times over their lifespan ## Footnote This strategy allows for more balanced reproductive efforts.

Question 28

What trade-off exists between the number of offspring and investment per offspring?

Answer 28

Producing many offspring with little chance of survival vs. fewer, larger offspring ## Footnote An intermediate approach often maximizes survival rates.

Question 29

What can population pyramids indicate?

Answer 29

Demographic trends in births and deaths ## Footnote They visually represent the age composition of a population.

Question 30

What is the expected effect of high costs of reproduction on individual reproductive strategies?

Answer 30

Individuals may defer or minimize current reproduction to enhance future survival ## Footnote This occurs when reproduction significantly affects future reproductive capabilities.

Question 31

What is the relationship between age at first reproduction and life span among mammals?

Answer 31

Longer-lived species tend to delay reproduction relative to their life span ## Footnote This allows juveniles to gain experience before reproducing.

Question 32

What is the effect of environmental limits on population growth?

Answer 32

Populations stabilize at a certain size due to shortages of resources ## Footnote Such limits can include space, light, water, or nutrients.

Question 33

What is characteristic of countries with stable populations?

Answer 33

A rectangular pyramid ## Footnote This shape indicates a balance between births and deaths.

Question 34

What shape is characteristic of a country that will exhibit rapid future growth?

Answer 34

A triangular pyramid ## Footnote This indicates that most of the population has not yet entered childbearing years.

Question 35

What shape indicates populations that are shrinking?

Answer 35

Inverted triangles ## Footnote These are often a result of sharply declining birth rates.

Question 36

What leads to evolutionary adaptation to environmental conditions?

Answer 36

Natural selection ## Footnote This process allows species to adapt to changing environments.

Question 37

What was observed in E. coli strains grown at high temperatures over 2000 generations?

Answer 37

Their efficiency in resource utilization improved by 30% ## Footnote The means of this efficiency increase is still unknown.

Question 38

What are the three important characteristics of population ecology?

Answer 38

* Population range * Spacing of individuals * Population size changes over time ## Footnote These characteristics help in understanding population dynamics.

Question 39

What does the term 'population range' refer to?

Answer 39

The area throughout which a population occurs ## Footnote This can vary from very limited to widely distributed ranges.

Question 40

What is an example of a species with a very limited geographic range?

Answer 40

Devil’s Hole pupfish ## Footnote This species lives in a single spring in southern Nevada.

Question 41

What adaptations do polar bears have for their environment?

Answer 41

Physiological adaptations for cold survival ## Footnote They are specially adapted to thrive in Arctic conditions.

Question 42

What defines the ability of an organism to maintain a steady-state internal environment?

Answer 42

Homeostasis ## Footnote This condition is crucial for survival in varying environments.

Question 43

What is Allen’s rule?

Answer 43

Mammals from colder climates have shorter ears and limbs ## Footnote This adaptation reduces heat loss.

Question 44

How do spadefoot toads adapt to desert conditions?

Answer 44

They burrow underground and reduce metabolic rates ## Footnote This allows them to survive long dry periods.

Question 45

True or False: All organisms can thrive in any environment.

Answer 45

False ## Footnote Each population has specific environmental requirements.

Question 46

What are key elements of the physical environment that affect organisms?

Answer 46

* Temperature * Water availability * Soil conditions ## Footnote These factors determine habitat suitability.

Question 47

What physiological adjustment do humans make at high altitudes?

Answer 47

Increased delivery of oxygen to body tissues ## Footnote This adjustment helps mitigate altitude sickness.

Question 48

What are conformers in the context of environmental adaptation?

Answer 48

Organisms that adopt the physical aspects of their surroundings ## Footnote They do not regulate their internal environment.

Question 49

What happens to population ranges over time?

Answer 49

They undergo expansion and contraction ## Footnote Environmental changes can lead to shifts in species ranges.

Question 50

What is a significant factor in determining resource use?

Answer 50

Per capita consumption ## Footnote This is crucial alongside population size.

Question 51

What percentage of the world's consumption of resources is accounted for by the wealthiest 20%?

Answer 51

86% ## Footnote This highlights the disparity in resource consumption globally.

Question 52

What major factor influences the future of humanity's population growth?

Answer 52

The balance between birth rates and death rates ## Footnote This dynamic is crucial for sustainable population levels.

Question 53

What adaptation allows some frogs to survive in arid climates?

Answer 53

Secreting a waxy substance to reduce water loss ## Footnote This adaptation minimizes dehydration.

Question 54

What is a common dispersal mechanism for plant seeds?

Answer 54

* Wind dispersal * Animal fur attachment * Digestive passage through animals ## Footnote These methods help seeds reach new areas.

Question 55

What is the projected global population stabilization figure by the mid-21st century?

Answer 55

About 8.9 billion people ## Footnote This projection considers current family planning efforts.

Question 56

True or False: Rapid population growth occurs primarily in developed countries.

Answer 56

False ## Footnote It is mainly centered in developing countries.

Question 57

What is one consequence of rapid population growth in developing countries?

Answer 57

Increased gap between rich and poor ## Footnote This disparity can lead to social and economic challenges.

Question 58

What has been the effect of family planning programs in Kenya from 1984 to 2008?

Answer 58

Reduced fertility rate from 8.0 to 4.7 children per couple ## Footnote This demonstrates success in population control efforts.

Question 59

What is a result of humans altering the environment in terms of species distribution?

Answer 59

Some species expand their ranges into new areas ## Footnote This can lead to ecological changes.

Question 60

What percentage of the global population in developing countries gets by on $1 per day?

Answer 60

About one-quarter ## Footnote This highlights extreme poverty levels in the developing world.

Question 61

Which part of the world consumes 80% of the total energy used today?

Answer 61

The industrialized world ## Footnote This shows the disparity in energy consumption between developed and developing countries.

Question 62

What is one effect of humans altering the environment on species distribution?

Answer 62

Some species, such as coyotes, expand their ranges and move into new areas ## Footnote This illustrates how human activity can impact wildlife habitats.

Question 63

What misguided attempt led to the introduction of starlings in New York City?

Answer 63

Establishing every species of bird mentioned by Shakespeare ## Footnote This resulted in a widespread population of starlings throughout the United States.

Question 64

What is the current annual growth rate of the human population?

Answer 64

78 million people per year ## Footnote This statistic emphasizes the rapid increase in human population size.

Question 65

What is the projected population of India by 2050?

Answer 65

Likely to exceed 1.6 billion ## Footnote This indicates significant population growth in rapidly developing countries.

Question 66

How does the population pyramid of Sweden differ from that of Kenya?

Answer 66

Sweden's is nearly rectangular, while Kenya's is very triangular ## Footnote This reflects differences in birth rates and life expectancy.

Question 67

What is the fertility rate in Sweden compared to Kenya?

Answer 67

1.7 in Sweden; 4.7 in Kenya ## Footnote Higher fertility rates in Kenya contribute to potential population doubling.

Question 68

What percentage of the world’s population lives in developing countries as of the 1990s?

Answer 68

90% of the billion people added ## Footnote This highlights the demographic shift towards developing countries.

Question 69

What is the ecological footprint?

Answer 69

The amount of productive land required to support an individual's standard of living ## Footnote This measure helps quantify resource use and sustainability.

Question 70

What is a metapopulation?

Answer 70

Distinct populations that may exchange members ## Footnote This concept describes the interactions between populations in fragmented habitats.

Question 71

What factors increase the likelihood of a population's extinction in source-sink metapopulations?

Answer 71

* Small population size * Isolation from sources of immigrants * Low resource availability * Lack of genetic variation ## Footnote These factors indicate vulnerabilities within metapopulations.

Question 72

What is clumped spacing in populations?

Answer 72

Individuals cluster in response to uneven resource distribution ## Footnote This distribution is common in nature due to environmental adaptations.

Question 73

What are the two types of spacing patterns in populations?

Answer 73

* Random spacing * Uniform spacing * Clumped spacing ## Footnote These patterns describe how individuals are distributed in different environments.

Question 74

What is uniform spacing often a result of?

Answer 74

Competition for resources ## Footnote This can occur through territorial behaviors or resource competition among plants.

Question 75

What does the term 'source-sink metapopulations' refer to?

Answer 75

Populations in better habitats (sources) support those in poorer habitats (sinks) ## Footnote This structure is crucial for maintaining population stability in varied environments.

Question 76

What can lead to the extinction of populations within a metapopulation?

Answer 76

Epidemic disease, catastrophic fire, or loss of genetic variation ## Footnote These events can disrupt population dynamics and lead to local extinctions.

Question 77

How does dispersal affect metapopulation dynamics?

Answer 77

Populations increasing in size send out many dispersers, while declining populations receive more immigrants ## Footnote This asymmetry affects population stability and growth.