Chapter 4: Ecosystems and Communities

Commensalism

A symbiotic relationship in which one organism benefits and the other is neither helped nor harmed

Parasitism

A symbiotic relationship in which an organism lives on or inside another organism and harms it

Mutualism

A symbiotic relationship in which both species benefit from the relationship

Predation

An interaction in which one animal (predator) captures and feeds on another animal (prey)

Underwater organisms

________ are affected by water depth.

Earths terrestrial ecosystems

________ are classified into ten groups of regional climate communities called biomes.

Weather

The day- to- day condition of Earths atmosphere

Currents

________ can dramatically affect water temperature by carrying water that is noticeably warmer or cooler than normal into a given area.

Food webs

________ in lakes and ponds often are based on plankton (a general term that includes both phytoplankton and zooplankton) and attached algae and plants.

Aquatic habitats

________ are warmer near the equator and colder near the poles.

Mountain ranges

________ exist on all continents and in many biomes; conditions such as temperature and precipitation vary with elevation.

Symbiosis

Any relationship in which two species live closely together

Organisms

________ in the intertidal zones are subjected to regular and extreme changes in temperature.

Predators

________ can affect the size of prey populations in a community.

Estuaries

Wetlands that form where a river meets the sea

Plant roots

Ex: ________ compete for water and nutrients in the soil and animals compete for food, mates, and space.

Herbivory

________ is an interaction in which one animal (________) feeds on producers (such as plants)

Competition

Occurs when organisms try to use a limited resource in the same place at the same time as other organisms

Plant communities

________ are mostly grasses maintained by periodic fires and heavy grazing.

Wetland

An ecosystem in which water either covers the soil or is present at or near the surface for at least part of the year

Deserts

________ have less than 25 centimeters of precipitation annually.

streams

Rivers, ________, creeks, and brooks often originate from underground water sources in mountains or hills.

Kelp forests

________ and coral reefs are two important coastal communities.

Latitude

________ and the transport of heat by winds and ocean currents also help shape global climate.

continental shelf

The open ocean begins at the edge of the ________ and is divided into the photic zone and the aphotic zone.

Global climate

________ is shaped by many factors, including solar energy trapped in the biosphere.

Freshwater ecosystems

________ can be divided into three main categories: rivers and streams, lakes and ponds, and freshwater wetlands.

Abiotic factors

________: hot and wet year- round; thin, nutrient- poor soils subject to erosion.

Ecologists

________ divide the ocean into zones based on depth and distance from shore.

Tall trees

________ form a dense, leafy covering called a canopy, which shades a layer of shorter trees and vines called the understory.

Biomes

________ are described in terms of abiotic factors like climate and soil type, as well biotic factors like plant and animal life.

Soils

________ are fertile and often rich in humus, a material formed from decaying leaves and other organic matter.

Waters circulation

________ between the surface and the benthos during some seasons distributes heat, oxygen, and nutrients.

Greenhouse effect

The process in which certain gases (carbon dioxide, methane, and water vapor) trap sunlight energy in Earth's atmosphere as heat

Environmental conditions

________ can vary over small distances, creating microclimates- ________ within a small area that differ significantly from the climate of the surrounding area.

coastal ocean

The ________ extends from the low- tide mark to the outer edge of the continental shelf

Animal life

________: camouflage helps insects and ground- dwelling mammals avoid predation.

Plant life

________: deciduous trees drop their leaves in autumn and go dormant in winter.

low tide

At ________, they (Organisms) are exposed to air and sunlight.

Fire

________ is a constant threat because of dense, low, oily plants.

mixture of fresh water

They contain a(n) ________ and salt water and are affected by ocean tides.

Temperate zones

________ and polar zones receive very different amounts of solar energy at different times of the year.

Water

________ may flow or remain still; wetlands help to prevent flooding by absorbing and slowly releasing water.

Greenhouse gases

________ in the atmosphere allow solar radiation to enter the biosphere, but they slow down the radiation of Earths heat back to space

Wetlands

________ are often nutrient- rich, highly productive breeding grounds.

Estuaries

________ serve as breeding and nursery grounds for many ecologically and commercially important fish and shellfish species.

Herbivores

________ can affect the size and distribution of plant populations in a community.

Underwater organisms

________ are affected by temperature and currents.

Abiotic factors

________: cold to moderate winters; warm summers; year- round precipitation; fertile soils.

Environmental conditions can vary over small distances, creating microclimates

environmental conditions within a small area that differ significantly from the climate of the surrounding area

Every species has its own range of tolerance

the ability to survive and reproduce under a range of environmental conditions

Ex

Plant roots compete for water and nutrients in the soil and animals compete for food, mates, and space

Ex

ticks feeding on a mammals blood and skin

Ex

Barnacles attached to, but not harming, a whale

Ex

lichen is a pioneer species that grows on bare rock

Abiotic factors

hot and wet year-round; thin, nutrient-poor soils subject to erosion

Plant life

understory plants use large leaves to compete for limited light

Animal life

animals are active all year

Abiotic factors

warm year-round; usually, a period of rain is followed by a long period of drought

Plant life

deciduous plants lose leaves to survive the dry season

Animal life

many animals enter long periods of inactivity called estivation (similar to hibernation) to reduce their need for water

Abiotic factors

warm, seasonal rainfall; compact soils, frequent fires set by lightning

Plant life

plant adaptations include waxy leaf coverings and seasonal leaf loss

Animal life

many animals migrate during the dry season to find water; some smaller animals burrow and remain inactive during the dry season

Abiotic factors

low precipitation; variable temperatures

Plant life

many plants store water in their tissues and minimize leaf surface area to cut down on water loss

Animal life

Many desert animals get water from the food they eat and are active at night to avoid the heat

Abiotic factors

warm to hot summers; cold winters; moderate seasonal precipitation; occasional fires

Plant life

grassland plants are resistant to grazing and fire

Animal life

predation is a threat for smaller animals because of the open environment; thus, camouflage and burrowing are common adaptations

Abiotic factors

hot dry summers; cool moist winters, thin, nutrient-poor soils; periodic fires

Plant life

plants have adapted to drought and have tough, waxy leaves that resist water loss

Animal life

animals tend to be browsers that eat varied diets of grasses, leaves, shrubs, and other vegetation

Abiotic factors

cold to moderate winters; warm summers; year-round precipitation; fertile soils

Plant life

deciduous trees drop their leaves in autumn and go dormant in winter

Animal life

animals must cope with changing weather; bare trees leave animals exposed in winter

Abiotic factors

mild temperatures; abundant precipitation in fall, winter, and spring; cool, dry summers

Plant life

less diverse than a tropical rain forest, but has ample water and nutrients to support their lush, dense, plant growth; trees here are among the worlds tallest

Animal life

camouflage helps insects and ground-dwelling mammals avoid predation

Abiotic factors

long cold winters, short mild summers; moderate precipitation; high humidity; acidic, nutrient-poor soils

Plant life

a conifers shape allows it to shed snow, and its wax-covered, needlelike leaves reduce water loss

Animal life

to stay warm, most animals have small limbs and ears, and fat or downy feathers for insulation

Abiotic factors

strong winds; low precipitation; short and soggy summers; long, cold, dark winters; permafrost

Plant life

mosses and other plants are low-growing to avoid damage from frequent strong winds

Animal life

many animals migrate to avoid long harsh winters, while animals that live in the tundra year-round have adaptations such as natural antifreeze to limit heat loss

Freshwater ecosystems can be divided into three main categories

rivers and streams, lakes and ponds, and freshwater wetlands

Continental shelf

The relatively shallow border that surrounds the continents

Climate

Refers to the average year-to-year conditions of temperature and precipitation in an area over a long period of time

Microclimates

Environmental conditions within a small area that differ significantly from the climate of the surrounding area

Tropical zone

Includes the areas near the equator and receives nearly direct sunlight all year

Tolerance

The ability to survive and reproduce under a range of environmental conditions

Habitat

The general place where an organism lives

Niche

The range of physical and biological conditions in which a species lives and the way in which the organism uses those conditions

Resources

Any necessity of life, such as water, nutrients, light, food, and space

Intraspecific competition

Competition among members of the same species

Interspecific competition

Competition between members of different species

Competitive exclusion principle

States that no two species can occupy the same niche in the same habitat at the same time

Herbivory

An interaction in which one animal (herbivore) feeds on producers (such as plants)

keystone species

Sometimes a population change in a single species can cause dramatic changes in its community; this species is called a _______

Ecological succession

A series of gradual changes that occur in a community following a disturbance