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55 terms

Chapter 4 Ecosystems and Communities

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biotic factors
biological influences on organisms within an ecosystem; birds, trees, mushrooms, bacteria
abiotic factors
physical (nonliving) factors that shape ecosystems; temperature, precipitation, humidity, wind, nutrient availability, soil type, sunlight
niche
full range of physical and biological conditions in which an organism lives
competition
when organisms of the same or different species attempt to use an ecological resource at the same place at the same time
resource
necessity of life; water, nutrients, light, food, space
competitive exclusion principle
no two species can occupy the same niche in the same habitat at the same time
predation
one organism captures and feeds on another organism
predator
organism that does the killing in predation
prey
organism that is the food in predation
symbiosis
relationship in which two species live closely together
mutualism
both species benefit from the relationship
commensalism
one member of the association benefits and the other is neither helped or hurt
parasitism
one organism lives on or inside another organism and harms it
host
organism from which a parasite obtains nutritional needs
ecological succession
gradual change in living communities that follows a disturbance
primary succession
succession that occurs where no soil exists
pioneer species
first species to populate an area when premary succession begins
secondary succession
follows when a disturbance changes a community without removing the soil
biome
group of ecosystems that have the same climate and dominant communities
climate diagram
summarazes average temperature and precipitation at a given location during each month of the year
microclimate
climate within a small area that differs significantly from the climate of the surrounding area
tropical rainforest
biome that occurs on or near the equator
tundra
biome that occurs near or above the 60 degree N latitude
boreal forest
forest biome that occurs almost exclusively in the Northern Hemisphere
canopy
dense covering formed by the leafy tops of tall trees
understory
layer of shorter trees and vines
deciduous tree
sheds its leaves during a particular season each year
grasslands
another name for tropical savannas
chaparral
communities that are dominated by shrubs
coniferous tree
produce seed bearing cones and have thin leaves shaped like needles
humus
material formed from decaying leaves and other organic matter
taiga
another name for boreal forests
permafrost
permanently frozen subsoil in the tundra
elevation
abiotic and biotic conditions of mountain ranges vary with ___________
depth
determines amount of light organisms recieve in water
chemistry
refers to amount of dissolved chemicals on which life depends in water
flowing-water, standing-water
two main types of freshwater ecosystems
plankton
tiny, free-floating organisms that occur in aquatic environments
phytoplankton
supported by nutrients in water; unicellular algae
zooplankton
feed on phytoplankton; planktonic animals
wetland
ecosystem in which water either covers the soil or is present at or near the surface of the soil for at least part of the year
brackish
salty water
bogs, marshes, swamps
three main types of freshwater wetlands
estuaries
wetlands formed where rivers meet the ocean
detritus
tiny pieces of decaying plants and animals that provide food for organisms at the base of the estuary food web
salt marshes
temperate-zone estuaries dominated by salt-tolerant grasses above the low tide-line and by seagrasses under water
mangrove swamps
coastal wetland dominated by mangroves, salt tolerant woody plants
photic zone
well-lite upper layer of the oceans
aphotic zone
permanently dark zone below the photic zone
intertidal zone, coastal ocean, open ocean
three main vertical divisions of the ocean based on the depth and distance from the shore
zonation
prominent horizontal banding of organisms that live in a particular habitat
kelp forests
huge forests of giant brown algae in the coastal ocean
coral reefs
primary structure made of skeletons of coral animals; all growth occurs within 40 meters of surface
benthic zone
covers the ocean floor
benthos
organisms that live attached to or near the bottom of the ocean