Chapter 42: Organisms in their Environment
Vocabulary:
Abiotic: nonliving components of an ecosystem
Adiabatically: When compressed gas is allowed to expand, it cools (occurring without a gain or
loss of heat)
Benthic environment: organisms that live in and on the ocean floor; see benthos
Benthos: the community of organisms that live in the seabed (benthic zone) including tidal pools,
continental shelf, and down to the abyssal depths.
Biome: distinct physical environment that is inhabited by ecologically similar organisms with
similar adaptations; convergent evolution
Biosphere: all the organisms and environments of the planet
Biotic: living components of an ecosystem.
Boreal forest (taiga): moist subarctic forest dominated by conifers that begins where tundra ends
Chaparral: shrubby plant community with a Mediterranean climate and sometimes wildfires
(California).
Climate Diagram: a summary of the climate at any location on the globe
Climate: average state and pattern of weather over a long period of time
Community: the assemblage of interacting populations of different species within a particular
geographic area
Coral reefs: underwater structures made from calcium carbonate secreted by coral; colonies of
animals found in marine waters with few nutrients; clustered polyps
Current: prevailing winds that drive massive circulation patterns in the surface waters of the
oceans
Desert: arid land with sparse vegetation; warm climate and very little sporadic rainfall
Ecological system: 1+ organisms and their external environment with which they interact
Ecology: the total relations of the animal both in its abiotic and biotic environment (Haeckel);
the conditions of the struggle for existence and drives natural selection (Darwin)
Ecosystem services: ecosystems that benefit humankind with resources; e.g. clean water and
decomposition
Ecosystem: communities plus their physical environment
Ecotone: integration of two biomes
Estuary: a water passage where the tide meets the river current creating brackish water
Euphotic zone (photic zone): enough sunlight for photosynthesis to occur underwater; near
surface
Eutrophic: lake or pond with high biological productivity; excessive nutrients which help
ecosystem to support an abundance of aquatic plants and algae
Flowing-water ecosystems (lotic): unidirectional flow; continuous physical change
Freshwater wetlands: land is covered by shallow water that floods regularly; brimming with life
Hadley cells: air circulation patterns of hot air that raises then cools and sinks back down
towards earth’s surface
Intertidal zone: see above
Kelp: protist brown algae; large sea weeds; grow in underwater forests; require nutrient rich
waters
Landscapes: multiple communities
Limnetic zone: open water area; also called pelagic zone; much phytoplankton
Littoral zone: near-shore regions of lakes and oceans; also called intertidal zone; shallow,
affected by wave action, periodically exposed to air by tidal action; complex vertical regions
Mangrove forests: where rainforests meet oceans; protect the coastline from erosion by
collecting sediment; mangroves have a bundle of aerial roots above the water to protect from
tides.
Marine snow: continuous shower of organic debris falling from upper layers of the water column
down into the deep ocean
Nekton: aggregate of actively swimming aquatic organisms in a body of water able to move
independently of water currents
Neritic province: forms the sublittoral zone; part of the ocean extending from the low tide mark
to the edge of the continental shelf; well-oxygenated water, low water pressure, stable temp and
salinity
Oceanic zone: area off shore in the ocean with depths greater than 200m; deep ocean water
Permafrost: permanently frozen layer at variable depth below the surface in frigid regions
Phytoplankton: microscopic diatoms; autotrophic components of the plankton community;
protists
Plankton: microscopic organisms that live in the water column and are incapable of swimming
against a current; crucial aquatic food source.
Population: a group of individuals of the same species that live, interact, and interbreed in a
particular geographic area at the same time
Profundal zone: deep zone of an inland freshwater body located below the range of light
penetration; temperature drops rapidly
Salt Marshes: a flat land subject to overflow by salt water
Savanna: tropical or subtropical grassland with scattered trees and drought-resistant undergrowth
Sea grasses: flowering plants that grow in marine, saline environments
Seasonality: greater fluctuations in temperature over the course of a year; result of uneven input
of solar radiation
Standing-water ecosystems (lentic): ranges from puddles to ponds to lakes to wetlands; divided
into water depth zones
Temperate deciduous: dominated by trees which lose their leaves each year; warm, moist
summers with mild winters
Temperate grassland: mostly grasses and shrubs; semi-arid to semi-humid; fertile soil and a
warm, hot season followed by a freezing winter season.
Temperate rain forest: woodland of a rather mild climate area within the temperate zone that
receives heavy rainfall and has numerous types of trees.
Topography: variation in elevation of Earth’s surface
Tropical rain forest: region around the equator; high temperatures and much rainfall; diverse life
Tundra: a level of rolling treeless plain in arctic or Antarctic regions; mucky black soil on top of
permanently frozen subsoil; mostly mosses, lichens, herbs, and shrubs
Weather: state of atmospheric conditions at a certain place and time
Zooplankton: organisms drifting in large bodies of water; variety of shapes and sizes