module 2 - human impact on the enivroment

What is population ecology?

The branch of ecology that studies population dynamics and how populations interact with their environment.

Why do scientists study population ecology?

To understand ecological balance, species interactions, and to inform conservation and management practices.

What is population size?

The total number of individuals within a population.

What is population density?

The number of individuals per unit area.

Why is population density important?

It influences competition, resource availability, disease spread, and other interactions among individuals.

What is population distribution?

The spatial arrangement of individuals within a habitat.

What are the three main population distribution patterns?

Clumped, uniform, and random distribution.

What is a clumped distribution?

A pattern where individuals are grouped together in clusters.

What is a uniform distribution?

A pattern where individuals are evenly spaced apart.

What is a random distribution?

A pattern where individuals are scattered unpredictably throughout an area.

Why can humans exhibit all three distribution patterns?

Different population scales and settlement patterns produce different distributions.

What is a density-dependent factor?

A limiting factor whose effects become stronger or weaker as population density changes.

How does resource availability act as a density-dependent factor?

As population density increases, resources per individual decrease.

How do biotic interactions act as density-dependent factors?

Competition, predation, and disease often increase as population density rises.

What are common density-dependent factors?

Food availability, space, predation, reproductive success, behavioral changes, and competition.

What is interspecific competition?

Competition between individuals of different species.

How is food availability a density-dependent factor?

More individuals compete for limited food resources as density increases.

How is space a density-dependent factor?

Higher densities reduce available living space for individuals.

How is predation pressure a density-dependent factor?

Predators often have greater impacts as prey populations become denser.

How can reproductive success be density-dependent?

Resource limitations and social interactions can affect breeding success at high densities.

How can behavior change with population density?

Increased density can alter social interactions, aggression, and movement patterns.

How are lynx and hare populations related?

Lynx populations typically rise after hare populations increase and decline after hare populations decrease.

What is a density-independent factor?

A factor that affects populations regardless of their density.

What types of factors are usually density-independent?

Abiotic factors such as weather, natural disasters, and human activity.

What four processes determine whether a population grows or shrinks?

Births, deaths, immigration, and emigration.

What is logistic growth?

Population growth that slows and stabilizes as environmental limits are reached.

Why do populations not grow infinitely?

Environmental resources are limited.

What is exponential growth?

A period of rapid population increase when resources are abundant.

Where does exponential growth occur on a logistic growth curve?

In the middle section where growth accelerates rapidly.

What is carrying capacity?

The maximum number of individuals an environment can sustainably support.

Why is carrying capacity important?

It represents the limit of population growth within an ecosystem.

Why is carrying capacity difficult to calculate?

It changes over time and depends on many environmental factors.

Is carrying capacity fixed?

No, it can vary seasonally, annually, and with technological or environmental changes.

How can technology affect carrying capacity?

Technological advances can increase the number of individuals an environment can support.

How do random events affect carrying capacity?

Unexpected events can increase or decrease available resources.

What characteristics make human populations different from other species?

Interconnectedness, cognitive thinking, and significant environmental impacts.

What factors helped human populations grow rapidly?

Agriculture, industrialization, medical advances, sanitation, and technology.

What is the Demographic Transition Model (DTM)?

A model that explains changes in birth and death rates as countries develop.

What characterizes Stage 1 of the Demographic Transition Model?

High birth rates, high death rates, and little population growth.

Are any countries currently in Stage 1 of the DTM?

No.

What characterizes Stage 2 of the Demographic Transition Model?

High birth rates, rapidly declining death rates, and rapid population growth.

What historical event is commonly associated with Stage 2?

The Industrial Revolution.

What characterizes Stage 3 of the Demographic Transition Model?

Birth rates begin to decline and population growth slows.

What characterizes Stage 4 of the Demographic Transition Model?

Low birth rates, low death rates, and a stable population.

What characterizes Stage 5 of the Demographic Transition Model?

Very low birth rates that may lead to population decline.

Why do birth rates often decline in later DTM stages? (4)

Increased education, urbanization, healthcare, and access to family planning.

How does female education affect birth rates?

Increased female education is strongly linked to reduced fertility rates.

How does family planning influence population growth?

It allows individuals to control family size and often reduces fertility rates.

What factor was found to have the strongest impact on fertility decline in the reading?

Contraceptive use.

What is population momentum?

The continued growth of a population after fertility rates decline because many individuals remain of reproductive age.

If fertility falls today, does population growth stop immediately?

No, population momentum can cause growth to continue.

What is a population pyramid?

A graph showing the age structure of a population.

Why are population pyramids useful?

They help predict future population trends and resource needs.

Who was Paul Ehrlich?

A population biologist and ecologist who wrote The Population Bomb.

What was The Population Bomb?

A 1968 book predicting severe population-related crises and starvation.

Why were Ehrlich's predictions inaccurate?

He underestimated future technological advancements and agricultural innovations.

What impact did The Population Bomb have?

It generated widespread public concern about overpopulation.

Does population size automatically determine environmental impact?

No.

Why are population studies important for economics?

Population trends affect labor forces, resources, and infrastructure needs.

Why are population studies important for public health?

They help predict and address healthcare needs.

Why are population studies important for urban planning?

They guide infrastructure and service development.

According to Charles C. Mann, what global population is expected by 2050?

Approximately 10 billion people.

What challenge does a population of 10 billion create?

Providing food, water, energy, and other necessities sustainably.

Who are the "Wizards" in Charles C. Mann's TED Talk?

People who believe technology and innovation can solve resource and environmental problems.

Who are the "Prophets" in Charles C. Mann's TED Talk?

People who believe society must reduce consumption and live within environmental limits.

What is Charles C. Mann's main argument?

Neither technology nor conservation alone is sufficient; both approaches are needed.