Population Ecology Concepts

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Questions and Answers

What is population density and how is it determined?

Population density is the number of individuals of a species per unit of area or volume at a given time, determined by biotic and abiotic factors in the environment.

Describe the three types of population dispersion.

The three types of population dispersion are random, clumped, and uniform. Random dispersion has individuals spaced unpredictably, clumped has individuals grouped together, and uniform has individuals evenly spaced.

What are the main factors that cause changes in population size?

The main factors are natality (birth rate) and mortality (death rate), along with immigration and emigration of individuals.

What does a positive population growth indicate?

Positive population growth indicates an increase in the population size (N). Signup and view all the answers

How does negative population growth affect the size of a species population?

Negative population growth results in a decrease in population size (N). Signup and view all the answers

Explain what is meant by zero population growth.

Zero population growth occurs when there is no net increase or decrease in population size (N). Signup and view all the answers

What potential does every species population have in terms of growth?

Every species population has the potential to expand greatly when resources are abundant. Signup and view all the answers

What are the implications of increased population density over time?

As population density increases, individuals typically access fewer resources, which can limit growth. Signup and view all the answers

What is population ecology and how does it relate to the environment?

Population ecology is the study of populations in relation to their environment, including how environmental factors influence population density, distribution, and dynamics. Signup and view all the answers

List four factors that cause changes in population size.

Birth rates, death rates, immigration, and emigration are four factors that cause changes in population size. Signup and view all the answers

Define the intrinsic rate of increase in populations.

The intrinsic rate of increase is the maximum potential growth rate of a population under ideal conditions with unlimited resources. Signup and view all the answers

Contrast J-shaped and S-shaped growth curves in population studies.

J-shaped growth curves represent exponential growth, while S-shaped curves show logistic growth, where population size levels off as it approaches carrying capacity. Signup and view all the answers

What are density-dependent factors in population ecology?

Density-dependent factors are influences on population size that vary with population density, such as competition, predation, and disease. Signup and view all the answers

Describe Type I survivorship curves and their implications for mortality.

Type I survivorship curves indicate high survival rates in early and middle life stages, with most mortality occurring in older age groups. Signup and view all the answers

Summarize the characteristics that define a population in ecology.

Characteristics defining a population include population density, dispersion patterns, birth and death rates, growth rates, survivorship, and age structure. Signup and view all the answers

Explain the significance of carrying capacity in population dynamics.

Carrying capacity is the maximum number of individuals an environment can sustain without degrading the habitat, affecting population growth and stability. Signup and view all the answers

What primarily contributed to the recent increase in the human population?

The primary contributor is a decrease in the death rate. Signup and view all the answers

How does the growth rate of a population change when the birth rate equals the death rate?

The growth rate will reach zero, indicating zero population growth. Signup and view all the answers

What is Earth's carrying capacity, and what factors influence its estimates?

Earth's carrying capacity ranges from 4 billion to 16 billion humans, influenced by living standards, resource consumption, and waste generation. Signup and view all the answers

In the case of Mexico, what patterns are observed in the birth and death rates during the 20th century?

Both birth and death rates declined, but the death rate declined much more significantly. Signup and view all the answers

What is the trend in the global per capita growth rate from the mid-1960s to 2013?

The global per capita growth rate declined from a peak of 2.2% per year to 1.2% per year. Signup and view all the answers

What effect does the accumulation of toxic waste have on population growth?

It slows down population growth and may lead to a decrease in population size due to poisoning. Signup and view all the answers

Define density independent factors and give two examples.

Density independent factors are environmental factors affecting population size regardless of population density; examples include temperature and water. Signup and view all the answers

How does temperature influence populations in an ecosystem?

Temperature affects enzyme activity in organisms, influencing their distribution and overall population sizes. Signup and view all the answers

Explain how light intensity impacts the distribution of organisms.

Light intensity influences the rate of photosynthesis in plants, which indirectly affects the number of consumers in the area. Signup and view all the answers

What role does water play in supporting population sizes in aquatic environments?

Water is essential for cellular metabolism and supports nutrient distribution; areas with good water supply can sustain more organisms. Signup and view all the answers

Describe the influence of wind on plant populations.

Wind can influence plant support, evaporation rates, and cause erosion, affecting the number of organisms that can thrive in those conditions. Signup and view all the answers

How does the presence of oxygen affect the distribution of organisms?

Higher oxygen levels support aerobic respiration, leading to a greater distribution of organisms that rely on oxygen. Signup and view all the answers

Contrast density dependent and density independent factors.

Density dependent factors are influenced by population density, while density independent factors are not and typically include abiotic conditions. Signup and view all the answers

What is biotic potential, and how does it relate to population growth?

Biotic potential refers to the maximum reproductive capacity of an organism under optimal environmental conditions, influencing the rate at which a population can grow. Signup and view all the answers

Explain the difference between density-dependent and density-independent factors affecting population size.

Density-dependent factors are influenced by population density, such as competition and disease, while density-independent factors affect populations regardless of their density, like natural disasters. Signup and view all the answers

How does carrying capacity affect population growth in an ecosystem?

Carrying capacity is the maximum number of individuals that an environment can sustainably support, which limits population growth when resources are scarce. Signup and view all the answers

What role does environmental resistance play in population dynamics?

Environmental resistance includes factors that limit population growth, such as lack of food, space, or adverse conditions, leading to mortality or reduced birth rates. Signup and view all the answers

Discuss the projections for population growth in less developed versus highly developed countries.

Less developed countries are projected to experience greater population growth due to higher natality rates, while highly developed countries often have lower growth due to various socio-economic factors. Signup and view all the answers

What are the two primary factors that must be greater for population growth to occur?

Birth rate must be greater than death rate, and immigration must be greater than emigration. Signup and view all the answers

What does the variable 'r' represent in population growth rate?

'r' represents the population growth rate, calculated as the birth rate minus the death rate. Signup and view all the answers

How is biotic potential defined in the context of population growth?

Biotic potential is the maximum rate at which a population can increase under ideal conditions. Signup and view all the answers

List two factors that influence a species' biotic potential.

The age of beginning reproduction and the species' reproductive span. Signup and view all the answers

What condition represents a stable population size?

When natality plus immigration equals mortality plus emigration. Signup and view all the answers

How is survivorship calculated in a population?

Survivorship is calculated as the number of survivors divided by the number in the original group, multiplied by 100. Signup and view all the answers

What is environmental resistance and how does it affect population growth?

Environmental resistance includes factors that limit the population's growth, such as limited resources or predation. Signup and view all the answers

Describe the relationship between carrying capacity and population growth.

Carrying capacity (K) is the maximum population size that an environment can sustain; population growth slows as it approaches this limit. Signup and view all the answers

Flashcards

Ecology

The study of how organisms interact with their environment, forming complex relationships.

Population

A group of individuals of the same species living in a particular area at a given time.

Population Ecology

The study of how populations change over time, including factors affecting their size and distribution.