Ecological Impacts

What is the change in composition of species, organisms and vegetation over time?

ecological succession

As ecological succession progresses, how are the diversity and biomass affected?

both diversity and

total biomass increase

What is the total mass of all living organisms in an ecosystem?

biomass

What is the number of species in a community?

diversity

(Note: specifically -

species richness)

What is the final successional stage of constant species composition achieved during ecological succession?

climax community

The climax community is unchanged until what occurrence?

blowout

(Note: a

catastrophic event)

Why is succession hard to predict?

succession has a factor of randomness

(Note: successional stages may not occur in an expected order)

What is the texture of an ecosystem that may change from solid rock, to fertile soil, to sand, or others?

substrate texture

What habitat condition may decrease due to the decomposition of organic matter such as acidic leaves?

soil pH

What habitat condition involves the ability of the soil to retain water?

soil water potential

(Note: changes as soil texture changes)

What habitat condition may change from full sunlight, to shady, to darkness as tress become established?

light availability

What habitat condition increases with population growth, and may be unsuitable to certain species?

crowding

What are the plants and animals that are the first to colonize a newly exposed habitat

pioneer species

Pioneer species are usually which types of species?

opportunistic,

r-selected species

(Note: can tolerate

harsh conditions)

As the soil, water, light of an ecosystem change, what organisms will replace the r-selected species?

k-selected species

Why do k-selected species slow down the rate of succession and reach climax where it remains for hundreds of years?

k- selected species live longer

What change occurs on substrates that have never previously supported living things, such as volcanic islands, lava flows, etc.?

primary succession

What is one of the most essential steps for primary succession?

soil building

What change begins in habitats where communities were entirely or partially destroyed by damaging events, such as fire, flood, etc.?

secondary succession

What is the key difference between primary and secondary succession?

primary: never supported life

secondary: previously supported life, already has soil

What is the species in a community that is the most abundant or collectively has the highest biomass?

dominant species

What is the species that is not usually abundant but exert control on their community structure through their pivotal ecological role?

keystone species

What are foundation species that dramatically alter their physical environment?

ecosystem engineers

Which species sits at the top of the food chain and no other creatures predate it?

apex predator

What are the categories that sort plants and animals based on their main energy source in an ecosystem?

trophic levels

What are autotrophs that convert the sun’s energy into chemical energy in an ecosystem?

primary producers

(Ex: plants, protists,

cyanobacteria, etc.)

How efficient are primary producers in converting the sun's energy into chemical energy?

convert only about 1%

of the energy available

What are herbivores with long digestive tracts with the greater surface area so there is more time for digestion in an ecosystem?

primary consumers

What organisms do primary consumers eat in an ecosystem?

primary producers

What organisms are primary carnivores that eat primary consumers in an ecosystem?

secondary consumers

What organisms are secondary carnivores that eat secondary consumers in an ecosystem?

tertiary consumers

What are consumers that obtain energy by consuming detritus (nonliving organic material)?

detritivores

(Note: can be

as small as

fungi or as large

as vultures)

What representations show the relationships between trophic levels, or biomass?

ecological pyramids

What term describes the proportion of energy represented at one trophic level that is transferred to the next?

ecological efficiency

(AKA: trophic efficiency)

On average, what percentage of a trophic level's energy is transferred to a higher trophic level?

10% of the energy

(Note: 90% lost to

metabolism/detritivores)

At which trophic level is energy/biomass/quantity the greatest?

primary producer level

(Note: lowest at

the tertiary consumer level)

Which trophic level is least stable and most sensitive to population fluctuations from the other levels?

tertiary level

What is the percentage of energy stored in assimilated food that is not used for respiration or excreted as feces?

production efficiency

Why do birds and mammals have low production efficiency?

use energy to maintain high body temperature

(Note: fish are higher, and insects/microbes are higher still)

What is a linear flow chart of who’s eaten by whom?

food chain

What is an expanded, more complete version of a food chain showing the complex relationships in an ecosystem?

food web

What does it mean if a community has a large number of pathways in its food web?

it is a stable community

What effect does the global burning of fossil fuels, deforestation, factory emissions, cars, etc. encompass?

global climate change

(Note: increase

CO2 in atmosphere)

What effect does increased CO2 have in the atmosphere?

more heat is

trapped, increasing

the greenhouse effect

What category of gases includes methane, CO2, ozone, CFC's, which all cause heat to build up in the lower atmosphere?

greenhouse gases

What problem results from CFC's (chlorofluorocarbons) entering the atmosphere and breaking down O3 (ozone)?

ozone depletion

Why is the ozone important?

protects land creatures

from ultraviolet radiation

What effect is caused when the burning of fossil fuels (e.g. coal) releases SO2 and NO2 which react with water vapor?

acid rain

(Note: sulfuric and nitric acid form)

What effect results from the overgrazing of grasslands that border deserts transform the grasslands into deserts?

desertification

(Note: agricultural

land or habitats are lost)

What is the clear-cutting of forests that cause erosion, flooding, and changes in weather patterns?

deforestation

What are the major problems with the slash and burn method of clearing tropical rain forests?

deforestation and increased greenhouse effect

(Note: nutrients in soil are destroyed also)

What effect occurs when air, water, and land pollution contaminate materials essential to life?

pollution

(Note: many

pollutants remain

in the environment

for decades)

What is the process of nutrient enrichment in lakes, which causes subsequent increases in biomass?

eutrophication

Lakes polluted with fertilizer runoff have abundant nutrients (especially phosphates), which stimulate what event?

algal blooms

How do algal blooms deplete oxygen in lakes?

respiration

How can algal blooms caused by eutrophication kill organisms?

oxygen starvation

(Note: lakes fill

with carcasses of

dead animals and plants)

What is the amount of added nutrient that can be absorbed by plants without damaging the ecosystem integrity?

critical load

(Note: usually

nitrogen or phosphorous)

When does runoff overwhelm and leach into multiple ecosystems?

when the critical load is exceeded

What process is a result of human activities, especially with regards to the destruction of their habitats?

reduction in species diversity

What problems can occur if humans accidentally or intentionally introduce new species to an environment?

1. invasive species prey on native organisms

2. invasive species outcompete native organisms

What substances are effective but are dangerous to humans?

pesticides

(Note: biological

control alternatives

are safer)

What are common biological control alternatives to pesticides?

1. crop rotation

2. natural enemies

3. insect birth control

What process occurs when one organism eats another, and toxins (e.g. pesticide) become concentrated at each higher trophic level?

biological magnification

(Note: antibiotics,

hormones, carcinogens,

teratogens, etc.)

What process includes using organisms to detoxify a polluted ecosystem?

bioremediation

What process includes using organisms to add essential materials to a degraded ecosystem?

biological augmentation

What is a species in danger of extinction?

endangered species

What is a species considered likely to become endangered soon?

threatened

What is a small area with numerous endemic species and a large number of endangered and threatened species?

biological hotspot

What process occurs when a small population size leads to inbreeding, and genetic drift has a significant effect?

extinction vortex

To avoid an extinction vortex, what metric must a population sustain?

minimum viable population

What are events that change communities by removing organisms or altering resource availability?

disturbances

(Ex: storm, flood, drought, human activity)

What process involves human activities increasing the acidity in the ocean?

ocean acidification

What are boundaries between ecosystems?

edges

What happens to a habitat if human alterations at a habitat edge create imbalances that favor edge-adapted species?

habitat fragmentation

What are small habitat clumps/strips connecting otherwise isolated patches in ecosystems?

movement corridors

Why are movement corridors important?

conserve biodiversity

What hypothesis suggests that low to moderate levels of disturbances increase species diversity, while high levels of disturbances reduce diversity?

intermediate disturbance hypothesis

What is the translocation of a species to a favorable habitat beyond its native range to protect it from human-caused threat?

assisted migration

What are areas of dry land that form on the leeward side (downwind) of a high mountain?

rain shadows

(Note: produce deserts)