CHAPTER 4,5 (AP Environmental Science)

Intraspecific competition

takes place between members of the same species.

Interspecific competition

takes place between

members of different species.

Competitive exclusion

If one species is a stronger competitor, it may exclude other species from the resource.

Species coexistence.

Otherwise, if no single competitor excludes others, species live side by side.

Niche

a species’ role in an ecosystem, including

resource use, habitat use, food consumption, and other

attributes.

Fundamental niche

The full potential niche of a species

Realized niche

An individual that only plays part of its role due to competition or other interactions

resource partitioning

where individuals use shared resources in different ways over many generations, in which natural selection may favor

character displacement

where competing species diverge and develop

different characteristics from resource partitionning

Parasitism

is a relationship where one organism depends on the other for nourishment.

• Parasites live with their hosts in many ways:

– Inside the host, such as tapeworms

– On the host’s exterior, such as sea lampreys

– Free living, such as cuckoos, who lay their eggs in the nests of other species

Pathogens

Parasites that cause disease

Coevolution

Parasites and hosts adapt and counter-adapt to each other

Herbivory

animals feed on the tissues of plants.

– Insects are the most common type of herbivore.

Mutualism

is a relationship where two or more species benefit each other.

Symbiosis (mutualistic relationship)

a close physical association between species.

Pollination

only require free-living organisms to encounter each other once.

▪ Birds or insects transfer pollen from flower to flower, causing fertilization.

Community

is an assemblage of populations of organisms living in the same area at the same time.

Community ecologists

study which species coexist, how they interact, how communities change over time, and why these patterns occur.

trophic level.

Species in a community are given a rank within the feeding hierarchy

Producers

use photosynthesis or chemosynthesis to make

their own sugars.

Primary consumers

consume producers.

Secondary consumers

prey on primary consumers.

Tertiary consumers

prey on secondary consumers.

Detritivores

scavenge waste and dead bodies.

Decomposers

break down nonliving matter into smaller molecules

that cycle back into soil.

Energy at each trophic level

• At each trophic level, most of the energy input is either used for maintenance or lost as heat.

– Trophic levels will only have about 10% of the energy content, organisms, and biomass compared to the one below them.

Biomass

is the collective mass of living matter in a given place and time.

Food chain

The flow of energy and feeding relationships from lower to higher trophic levels is depicted in a

Food webs

incorporate all of the interlinking food chains within an entire community, showing the map of energy flow.

Keystone Species

A species that has an impact far greater than its

abundance.

Include the following:

– Decomposers, which recycle nutrients and replenish

the soil

– “Ecosystem engineers,” such as beavers and prairie

dogs, which physically alter ecosystems

– Top predators, which control populations of lower

trophic level consumers

Trophic cascade

If top predators are lost, primary

consumers will over consume producers and alter the entire ecosystem.

Disturbance

any event that has rapid and drastic

effects on the community and ecosystem.

– can be small and localized, such as a tree falling and creating a gap in the forest canopy.

– can be large, like hurricanes.

– may also recur regularly, such as prairie fires or insect outbreaks.

Resistance

A community that resists change and remains stable

shows ______ to the disturbance.

Resilience

A community that is changed by a disturbance but returns to its original state

Succession

Severe disturbances may eliminate all or most of the

species in a community, initiating a series of changes

Pioneer Species

Succession begins with the colonization of ______ ________.

• spread over long distances easily and are adapted for growing quickly.

Climax community species

Over time, pioneers are overtaken by longer-living ___________, such as hardwood trees.

Primary succession

occurs when a disturbance removes all plant or soil life.

– Lichens secrete acids that break down rock, beginning the process of soil

formation.

Secondary succession

begins with a disturbance that alters the community but leaves the soil life intact.

– Farming, fires, storms, and landslides are examples.

Regime Shift

meaning that the entire character of the community changes due to the disturbance.

– This can occur from climate change, loss of a keystone

species, or introduction of an invasive species.

No-analog communities

Caused by human disturbances in some cases, which are mixtures of species that have not previously occurred on Earth.

Introduced species

Introduced species brought by people.

Invasive Species

Most fail to establish populations, but the ones that thrive

Eradication

the total elimination of a population, is very difficult and expensive.

– Managers instead aim to control populations with trapping, poisoning, and other techniques.

Restoration Ecology

devise ways to restore altered areas to their condition before industrialized civilization

Ecological restoration 2 aims

– Restore the functionality of an ecosystem.

– Return a community to its “pre-settlement” condition.

Biome

A regional complex of similar communities

– are classified primarily by dominant plant type and vegetation structure, which in turn is the result of climate.

Rainshadow effect

Mountains also affect climate through the _________

– When moist air moves up a steep slope, it cools and

condenses, releasing precipitation.

Climate diagrams, also called climatographs

depict seasonal changes in temperature and precipitation and help to tell the story of a biome.

Temperate deciduous forests

are found at midlatitudes and have relatively even precipitation throughout the year.

– Winters are frozen, causing the trees to drop their leaves.

Temperate grasslands

Temperature differences between winter and summer are more extreme and rainfall diminishes

– These biomes are also known as prairie or steppe.

Temperate rainforests

are rich in rainfall, but still found in midlatitudes.

– Mostly contain coniferous trees.

– Soils are fertile, but susceptible to erosion if the forests are

cleared.

Tropical rainforests

have dark, damp interiors, lush vegetation, and highly diverse communities.

– High numbers of tree species intermixed at low densities

– Acidic soils that are low in organic matter

Tropical dry forests

have wet and dry seasons that each occupy about half of the year.

– Temperature is consistently warm.

– Leaves are shed

Savannas

are tropical grasslands interspersed with acacias or other

trees.

– Found in dry tropical areas, including parts of Africa, Australia, and India

– Distinct wet and dry seasons

Deserts

are the driest biome, receiving less than 25 cm of rain per year.

– Soils have high mineral and low organic matter content.

– Animals and plants must adapt

Tundras

are also very dry but are consistently cold all year.

• are unoccupied by humans but are the most directly impacted by air pollution and climate change.

Boreal forests

also called taiga, are also cold, but receive more precipitation than tundras.

– They are dominated by few species of evergreen trees.

– Soils are acidic and nutrient-poor.

Chaparral

is found in only a few small patches throughout the world.

– Covered by a dense thicket of evergreen shrubs

– Mild, wet winters and warm, dry summers

– Fires are frequent.

– Climate is influenced by nearby oceans.

Watershed

an area of land that drains into a body of water through rivers, delivers nutrients that sustained fields of underwater grasses.

– The grasses provided a habitat for fish and shellfish.

– Oysters kept the water clear by filtering nutrients and

phytoplankton.

Hypoxia

When decomposition of dead plankton has depletes the water

Lithosphere

is the rock and sediment in the upper mantle and crust.

Atmosphere

Air surrounding the planet

Hydrosphere

includes all surface, underground, and atmospheric water

Biosphere

consists of all the planets organisms and the abiotic portions they interact with

Abiotic

Non-living / not alive

Emergent properties

Systems with characteristics that are not evident from their components alone

(ex: studying the cell and tissue organization of a tree would not predict its importance as a habitat or food source.)

Feedback Loop

A system’s output may serve as input back into the same system, a

process

Negative Feedback loop

results when a system moving in one direction acts as an input that causes the system to move in the opposite direction.

– enhances stability in a system.

Positive Feedback Loops

occur when increased output in a system leads to increased input, which further stimulates output.

(ex: The accelerating melting of glaciers and sea ice in the Arctic is an example.)

Dynamic equilibrium

Negative feedback systems with processes that move in opposing directions at equivalent rates

Homeostatsis

the tendency of a system to maintain stable internal conditions.

Runoff

precipitation that flows over land and into waterways

Airshed

the geographic area that produces pollutants likely to end up in a waterway

Eutrophication

occurs as bacteria deplete oxygen, suffocating other organisms.

Ecosystem

consists of all organisms and nonliving entities that occur and interact in a particular area at the same time.

– Ecological communities include only living organisms.

Estuary

is an ecosystem where rivers flow into the ocean, mixing salt and fresh water.

– Organisms are affected by the flow of water, nutrients, and sediment from the rivers.

– The chemical and physical conditions of the bay’s waters are affected by the photosynthesis, respiration, and decomposition of its life.

Primary production

The conversion of solar energy into chemical bonds in sugars

Gross Primary production

The total chemical energy produced by autotrophs

Net primary production

The energy that remains after respiration is used to generate biomass

-Freshwater wetlands, tropical forests, coral reefs, and algal beds

Secondary production

Energy used by consumers to generate their own biomass

Productivity

The rate at which solar energy is converted to biomass

Nutrients

elements and compounds that organisms require for survival.

Macronutrients

Elements and compounds (nitrogen, carbon, phosphorus) needed in large amounts

Micronutrients

Nutrients needed in smaller amounts (zinc, copper, iron)

Ecotones

Areas where ecosystems meet in a transitional zone

Landscape ecology

Due to the intermixing of ecosystems, ecologists may view systems on a larger geographic scale that includes multiple ecosystems.

Patches

A landscape is made of a spatial array _____ which may be specific ecosystems or areas of habitat of an organism.

• Traveling between _____ is dangerous and energy-intensive

• If far enough apart, a population may be divided to subpopulations

• If highly isolated individuals may not be able to move between them at all → creates extinction risk within subpopulations

Mosaic

Patches are spread out spatially over a landscape in a _______.

Metapopulation

A network of subpopulations, with limited movement between patches

Conservation biologists

study the loss, protection, and restoration of biodiversity, for ex: when patches isolation

Geographic information system (GIS).

Research tool that takes multiple types of data (geology, topography,

vegetation, etc.) and combines them into layers on a set of geographic coordinates.

Model

a simplified representation of a complex natural process.

Ecological modeling

involves constructing and testing models to explain and predict ecological

systems.

Nutrient cycles / Biogeochemical cycles

Nutrients move through ecosystems in ______ cycles

– Elements or molecules travel through the atmosphere, hydrosphere, lithosphere, and biosphere in dynamic equilibrium.

Reservoir / pool

Where nutrients move from one to the other in varying amounts of time, called the residence time

Source

When a reservoir releases more materials than it accepts

Sink

When a reservoir accepts more materials than it releases

Flux

the rate at which materials move between reservoirs.

Water in biochemical reactions

Water is the medium for all biochemical reactions, and it plays key roles in nearly every environmental system.

– Carries nutrients, sediments, and pollution

– Returns atmospheric pollutants to the surface through rain or snow