Chapter 42: Organisms in their Environment
Terms:
Abiotic: nonliving
Biotic: alive
Ecological system: One or more organisms plus the external environment with
which they interact.
Ecology: The scientific study of the interaction of organisms with their living
(biotic) and nonliving (abiotic) environments.
Population: Any group of organisms coexisting at the same time and in the same
place and capable of interbreeding with one another
Community: Any ecologically integrated group of species of microorganisms,
plants, and animals inhabiting a given area
Landscapes: A portion of land or territory which the eye can comprehend in a
single view, including all the objects it contains
Biosphere: All regions of Earth (terrestrial and aquatic) and Earth’s atmosphere in
which organisms can live.
Ecosystem: The organisms of a particular habitat, such as a pond or forest,
together with the physical environment in which they live
Weather: The state of atmospheric conditions in a particular place at a particular
time
Climate: The long-term average atmospheric conditions (temperature,
precipitation, humidity, wind direction and velocity) found in a region
Seasonality: A aspect of climate characterized by fluctuations in temperature over
the course of a year.
Adiabatically: occurring without gain or loss of heat
Hadley cells: Patterns of vertical atmospheric circulation that influence surface
winds and precipitation patterns according to latitude
Current: Circulation patterns in the surface waters of oceans driven by the
prevailing winds.
Climate diagram: A way of graphically summarizing the climate in a given
location by superimposing graphs of average monthly temperature and average
precipitation through a year.
Topography: The variations in the elevation of Earth’s surface that form, for
example, mountains and valleys
Biome: A major division of the ecological communities of Earth, characterized
primarily by distinctive vegetation. A given biogeographic region contains many
different biomes.
Permafrost: soil at or below the freezing point of water 0 °C for two or more years
Tundra: one of the vast, nearly level, treeless plains of the arctic regions of
Europe, Asia, and North America.
Boreal forest (taiga): vegetation composed primarily of cone-bearing, needleleaved, or scale-leaved evergreen trees, found in regions that have long winters and
moderate to high annual precipitation
Temperate rain forest: coniferous or broadleaf forests that occur in the temperate
zone and receive high rainfall
Temperate deciduous: dominated by trees that lose their leaves each year. They
are found in areas with warm, moist summers and mild winters
Temperate grassland: terrestrial biome whose predominant vegetation consists of
grasses and/or shrubs. The climate is temperate and ranges from semi-arid to semi-humid
Chaparral: a dense growth of shrubs or small trees
Desert: a region so arid because of little rainfall that it supports only sparse and
widely spaced vegetation or no vegetation at all
Savanna: grassland region with scattered trees, grading into either open plain or
woodland, usually in subtropical or tropical region
Tropical rain forest: luxuriant forest, generally composed of broad-leaved trees
and found in wet tropical uplands and lowlands around the Equator.
Plankton: Free-floating small aquatic organisms.
Nekton: the aggregate of actively swimming aquatic organisms in a body of
water, able to move independently of water currents.
Benthos: the biogeographic region that includes the bottom of a lake, sea, or
ocean, and the littoral and supralittoral zones of the shore.
Phytoplankton: Photosynthetic members of the plankton
Zooplankton: the aggregate of animal or animallike organisms in plankton, as
protozoans.
Flowing-water ecosystems: includes biotic (living) interactions amongst plants,
animals and micro-organisms, as well as abiotic (nonliving) physical and chemical
interactions is a moving body of water like a river or ocean; lotic ecosystem
Standing-water ecosystems: includes biotic (living) interactions amongst plants, animals
and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions in
a non-moving body of water such as a pond, swamp, marsh, or bog
Littoral zone: The nearshore region of a lake that is shallow and is affected by
wave action and fluctuations in water level
Limnetic zone: The open-water region of a lake
Profundal zone: deep zone of an inland body of freestanding water, such as a lake
or pond, located below the range of effective light penetration
Freshwater wetlands: inland area inundated with 1–6 feet of water, containing a
variety of perennials (mostly grasses), forbs (flowers), and bushes, rather than trees, as in
swamps.
Ecosystem services: Processes by which ecosystems maintain resources that
benefit human society.
Estuary: that part of the mouth or lower course of a river in which the river's
current meets the sea's tide.
Salt marshes: a coastal ecosystem in the upper coastal intertidal zone between
land and open salt water or brackish water that is regularly flooded by the tides
Mangrove forests: grow in areas with low-oxygen soil, where slow-moving
waters allow fine sediments to accumulate at tropical and subtropical latitudes; roots
make them appear to be on stilts, which allow them to handle the tides; collect much
sediment; stabilize coastline
Intertidal zone: A nearshore region of oceans that is periodically exposed to the
air as the tides rise and fall.
Benthic environment: The bottom of the ocean
Sea grasses: flowering plants which grow in marine, fully saline environments
Kelps: any large, brown, cold-water seaweed of the family Laminariaceae, used as
food and in various manufacturing processes.
Coral reefs: A mound or ridge of living coral, coral skeletons, and calcium
carbonate deposits from other organisms such as calcareous algae, mollusks, and
protozoans; form in warm, shallow sea waters and rise to or near the surface
Neritic province: relatively shallow part of the ocean above the drop-off of the
continental shelf, approximately 200m in depth; forms a relatively stable and wellilluminated environment for marine life, from plankton up to large fish and corals; where
the oceanic system interacts with the coast
Euphotic zone: the layer of sea water that receives enough sunlight for
photosynthesis to occur: it varies greatly with season and latitude, from 0 to 1200 ft
Oceanic province: all the open waters beyond the continental shelf
Marine snow: small particles of organic biogenic marine sediment, including the
remains of organisms, faecal matter, and the shells of planktonic oganisms, that slowly
drift down to the sea floor
Eutrophic: The addition of nutrient materials to a body of water, resulting in
changes in ecological processes and species composition therein.
Ecotone: the transition zone between two different plant communities, as that
between forest and prairie
Questions:
1. Abiotic factors, like water and soil, of the environment are nonliving; while,
biotic factors, plants and rabbits, are made up of living components.
2. Weather is the state of atmospheric conditions in a particular place at a
particular time; whereas, climate is the long-term average atmospheric
conditions in a region. Climate is what is expected and temperate is what
happens.
3. Latitude affects the temperature. For each degree of latitudinal increase away
from the equator, the temperate decreases by about 0.8 degrees Celsius. Since
the Earth is spherical, there is more solar energy at lower latitudes, closer to
the equator, and less solar energy at higher latitudes, near the poles.
Seasonality is when the temperate fluctuates over the course of the year. High
latitudes experience a more pronounced seasonality. Because the Earth is
tilted 23.5 degrees, different latitudes to reach their peak in solar energy at
different times during the year. This tilt causes the southern hemisphere to
have its winter at the time the northern hemisphere experiences summer.
4. Atmospheric circulation occurs when the air absorbs solar radiation, heats up,
expands, rises, flows, cools and falls. As water molecules absorb water in the
tropics, they evaporate enriching the tropic air with water vapor. As the air
cools, the water vapor forms into droplets and falls to the earth as rain.
However, around 30 degrees N and S the air is depleted of water vapor, and
little water falls here. The deserts are located at these latitudes. Winds drive
circulation patterns at the surface water – currents. Water has a high heat
capacity, so it loses heat slowly. Polar ward-flowing ocean currents carry heat
from the tropics to the poles.
5. A biome is a major division of the ecological communities of Earth,
characterized primarily by ecologically similar organisms with similar
adaptations and distinctive vegetation. A given biogeographic region contains
many different biomes.

Tropical rain forest – annual precipitation over 250cm, average
temperature over 20 C, diverse animals and plants, deep nutrient
depleted soil

Tropical seasonal forest - annual precipitation between 75-270cm,
average temperature over 17 C, diverse soil, plants and animals
adapted to seasons

Subtropical desert - annual precipitation between 75-250 cm, average
temperature over 16 C, little flora and fauna, nutrient rich soil

Temperate rain forest - annual precipitation between 175-350 cm,
average temperature between 4 - 20 C, diverse animals and plants,
deep nutrient depleted soil

Temperate seasonal forest - annual precipitation between 50-250cm,
average temperature between 0-16 C, nutrient rich soil, plants and
animals adapted to seasons

Woodland - annual precipitation between 0-120cm, average
temperature between -10 to 16 C, poor soil, nocturnal animals and
short plants

Temperate grassland - annual precipitation below 50cm, average
temperature between -10 to 16 C, nutrient rich soil, grasses and little
animals

Boreal forest - annual precipitation between 50-200cm, average
temperature between -5 to 5 C, poor soil, coniferous plants and cold
adapted animals

Tundra - annual precipitation below 100cm, average temperature
below -5 C, poor soil, little flora and fauna
6.

Tropical rain forest – many of the forest were cut down to use the
wood for building houses, ships, furniture, and paper

Tropical seasonal forest – forest clearing and wood collecting

Subtropical desert – off roading carves tracks into deserts that can kill
off vegetation and pollute the soil

Temperate rain forest – Farming, hunting logging, and urbanization
have caused less biodiversity in this region

Temperate seasonal forest – many of the forest were cut down to use
the wood for building houses, ships, furniture, and paper

Woodland – humans have turned much woodland into developed areas
for human use

Temperate grassland – many animals have been hunted to the brink of
extinction ex. bison

Boreal forest – many boreal areas have been destroyed by deforesting
so humans can use the land

Tundra – due to human pollution, the earth has been undergoing a
climate change, and the polar regions are becoming warmer. This has
caused the permafrost to melt, and the melting has caused problems for
the species inhabiting the area
7.
8. Abiotic factors like depth, movement, temperate, pressure, salinity, and
substrate affect aquatic biomes.