AP Environmental Science Unit 3

Explain the nitrogen cycle process of Fixation

Converts atmospheric nitrogen gas into reactive ammonia using specialized organisms or abiotic events.

Explain the nitrogen cycle process of Denitrification

Converts soil nitrates back into atmospheric nitrogen gas under anaerobic conditions.

Explain the nitrogen cycle process of Ammonification

Breaks down organic waste and dead matter into ammonia and ammonium.

Explain the nitrogen cycle process of Assimilation

Enables plant roots to absorb nitrates or ammonium to build essential biological molecules.

Which nitrogen cycle processes require bacteria?

Fixation Denitrification and Ammonification.

Describe the role of a keystone species in an ecosystem

Exerts a disproportionately large control on community structure and biodiversity relative to its abundance.

Identify specific examples of a keystone species

Sea otters gray wolves and African elephants.

Describe the characteristics of a K-selected species

Large body size long lifespan slow development low offspring count and high parental investment.

Identify specific animal examples of K-selected species

Elephants whales humans gorillas and rhinos.

Describe the characteristics of an r-selected species

Small body size short lifespan rapid maturation high offspring yield and minimal parental care.

Identify specific animal examples of r-selected species

Mosquitoes mice frogs jellyfish and locusts.

Describe the parental care strategy of a Type I survivorship curve

High investment per individual with most offspring surviving to old age.

Describe the parental care strategy of a Type II survivorship curve

Moderate consistent care with a steady mortality rate throughout life.

Describe the parental care strategy of a Type III survivorship curve

Minimal to no investment with high early mortality for offspring.

Identify examples of organisms that exhibit a Type I survivorship curve

Humans whales and elephants.

Identify examples of organisms that exhibit a Type II survivorship curve

Songbirds squirrels and reptiles.

Identify examples of organisms that exhibit a Type III survivorship curve

Oysters sea urchins and salmon.

Identify the survivorship curve generally exhibited by an r-selected species

Type III survivorship curve.

Identify the survivorship curve generally exhibited by a K-selected species

Type I survivorship curve.

Explain the environmental impact of invasive species

Alters habitat structure outcompetes native biota and reduces biodiversity.

Explain the economic impact of invasive species

Damages infrastructure and causes substantial agricultural or forestry losses.

Identify specific examples of invasive animal species and their impacts

Zebra mussels clog water pipes cane toads poison predators and Asian carp disrupt freshwater food webs.

Explain why invasive species tend to be r-selected

Leverages rapid reproduction high offspring count generalist diet tolerance and fast maturation to quickly colonize disturbed ecosystems.

Explain physical methods used to control invasive species

Manual removal trapping or installing physical barriers.

Explain chemical methods used to control invasive species

Applying targeted pesticides or herbicides to eliminate target populations.

Explain biological methods used to control invasive species

Releasing specific natural predators or pathogens from the native range.

Explain regulatory methods used to control invasive species

Implementing strict biosecurity policies and inspections at borders.

Describe a J-shaped biotic potential growth curve on a population graph

Represents rapid exponential population expansion when resources are unlimited.

Describe an S-shaped logistic growth curve on a population graph

Represents population expansion that slows and stabilizes as resources become limited.

Define carrying capacity on a population graph

Represents the maximum population size an environment can sustainably support over time.

Define population overshoot on a population graph

Occurs when a population temporarily exceeds resource limits leading to degradation and a subsequent die-off.

Define density-dependent limiting factors

Factors that vary in intensity with population density such as competition disease and predation.

Define density-independent limiting factors

Factors that affect populations regardless of density such as natural disasters drought and extreme temperatures.

Explain why predator populations lag behind prey populations on a graph

Abundance depends directly on food availability so resource availability drives subsequent shifts in consumer reproduction and survival.

Describe how a rapid population growth rate is interpreted from a population pyramid shape

Indicated by a wide base and narrow top.

Describe how a stable population growth rate is interpreted from a population pyramid shape

Indicated by a relatively uniform column width from base to top.

Describe how a declining population growth rate is interpreted from a population pyramid shape

Indicated by a narrow base that is smaller than the middle age groups.

Define Total Fertility Rate

The average number of children born to a woman during her reproductive years.

Identify social factors that impact the Total Fertility Rate of a country

Female access to education employment opportunities and delayed age of marriage.

Identify medical factors that impact the Total Fertility Rate of a country

Access to healthcare contraceptives and family planning services.

Describe how Total Fertility Rate changes as a country undergoes demographic transition

Drops from high levels to near or below replacement level.

Explain why Total Fertility Rate decreases during demographic transition

Driven by urbanization expanding female education access to family planning and declining child mortality.

Define Infant Mortality Rate

Measures the number of deaths of infants under one year old per one thousand live births.

Explain how Infant Mortality Rate changes as a country becomes more developed

Decreases significantly due to improved medical care sanitation and nutrition.

Explain the connection between Infant Mortality Rate and Total Fertility Rate

High infant mortality directly drives high fertility because families have more children to ensure survival to adulthood.

Explain why increased female access to education causes Total Fertility Rate to drop

Delays marriage and childbirth while raising the economic opportunity cost of raising large families.

Explain how healthcare improvements lower Infant Mortality Rate

Provides better prenatal care vaccinations clean water and disease prevention.

Explain how healthcare improvements lower Total Fertility Rate

Reduces child mortality so parents no longer need extra births to ensure offspring survival.

Identify the primary reason humans avoided the Malthusian carrying capacity

Technological innovation in agriculture through the Industrial and Green Revolutions vastly increased food supply.

Identify the characteristics of Stage 1 in demographic transition

High birth rates and high death rates resulting in low net population growth.

Identify the characteristics of Stage 2 in demographic transition

High birth rates and rapidly declining death rates resulting in rapid population growth.

Identify the characteristics of Stage 3 in demographic transition

Declining birth rates and low death rates resulting in slowing population growth.

Identify the characteristics of Stage 4 in demographic transition

Low birth rates and low death rates resulting in zero growth or population stabilization.

Identify the demographic transition stage with the highest population growth rate

Stage 2.

Explain why the highest population growth occurs during Stage 2 of demographic transition

Death rates drop rapidly due to medical advances while birth rates remain elevated.

Explain how educational policies can reduce population growth

Expanding access to secondary schooling for young women delays childbearing.

Explain how family planning policies can reduce population growth

Providing subsidized contraceptives and financial incentives for smaller families.

What is the formula to calculate percent change in a population?

Subtract initial value from final value divide by initial value and multiply by one hundred.

How do you calculate new population size given births deaths and immigration?

Add births and immigrants to initial size and subtract deaths.

What is the formula to calculate population growth rate from crude rates?

Subtract Crude Death Rate from Crude Birth Rate and divide by ten.

What is the Rule of 70 formula used to calculate doubling time?

Divide seventy by the population growth rate percentage.

What methods can be used to control an oversized human population?

Expanding reproductive healthcare improving female education offering voluntary financial incentives and implementing regulatory limits.

Explain when generalist species are at an ecological advantage

Generalists thrive in changing or unstable environments due to their broad niche and adaptable diet.

Explain when specialist species are at an ecological advantage

Specialists thrive in stable environments by outcompeting other species for specific resources.

Identify an example of a species that does not clearly fit into r-selected or K-selected categories

Sea turtles exhibit large body size and long lifespans like K-selected species while laying hundreds of eggs with no parental care like r-selected species.

Which type of species is most vulnerable to the impact of invasive species?

K-selected species are most vulnerable due to low reproductive rates and slow population recovery.

Define population dieback on a population graph

A rapid decline in population size that occurs directly after an overshoot of carrying capacity.

Define fecundity in population ecology

The physical ability or potential rate of an organism to reproduce offspring.

Define family planning in human population studies

The practice of controlling the timing and number of children born using education and contraception.

Identify the three major age structure categories on a population pyramid

Pre-reproductive reproductive and post-reproductive age groups.

What demographic trend is characterized by a Stage 5 population pyramid?

A shrinking population caused by a birth rate dropping significantly below the death rate.

Describe the shape of the total population line in Stage 2 of demographic transition

Steeply rising upward as the gap between birth and death rates widens.

Describe the shape of the Crude Birth Rate curve across the demographic transition stages

High and stable through Stage 1 and Stage 2 before dropping steeply in Stage 3 and leveling off low in Stage 4.

Describe how a population-time graph looks when a species exceeds carrying capacity

A peak above the carrying capacity line followed by a steep downward dieback line.

How would a population pyramid look for a country receiving a large influx of male migrant workers

A noticeable outward bulge in working-age cohorts specifically on the male side.

How would a population graph look if an agricultural breakthrough increases available food

The horizontal carrying capacity line shifts upward allowing the population curve to grow to a higher level.