the evolution of a single ancestor species into several
new species within a relatively short period of time and
in a certain geographic area. The plants and animals of
the Galápagos Islands are a result of adaptive radiation,
where one plant or one animal species diversified into
many species that fill a variety of ecological roles. For
example, more than a dozen species of finches evolved
from a single founding species that colonized the islands
from the mainland of South America.
living predominantly or entirely in trees
a ring-shaped coral reef or string of coral islands,
usually enclosing a shallow lagoon
the variety of life on Earth and the interconnections
among living things
the study of living systems and their distribution.
Biogeography is important to the study of the Earth’s
biodiversity because it helps with understanding where
animals and plants live, where they don’t, and why.
refers to the living components of the environment
(such as plants, animals, and fungi) that affect
pertaining to the north
slightly salty or briny. Brackish water is saltier than
fresh water but less salty than seawater.
fishes, or any other animals, that are accidentally caught
in fishing gear
a characteristic group of plants and animals living and
interacting with one another in a specific region under
similar environmental conditions
the large-scale removal of trees from a habitat
dominated by forest
the sonar-like ability used by bats, dolphins, and other
animals to detect objects. Using echolocation, the
animal emits high-pitched sounds that reflect off of an
object and return to the ears or other sensory receptors.
valuable services provided by natural systems.
Examples of ecological services include flood control,
air purification, and climate control.
a geographically distinct area of land that is
characterized by a distinctive climate, ecological
features, and plant and animal communities. The
Klamath-Siskiyou Coniferous Forests in the U.S. Pacific
Northwest is an example of an ecoregion.
a community of plants, animals, and microorganisms
that are linked by energy and nutrient flows and that
interact with each other and with the physical
environment. Rain forests, deserts, coral reefs,
grasslands, and a rotting log are all examples of
a species threatened with extinction. The Florida
panther and the California condor are endangered
species that naturally occurs in only one area or region.
For example, the redfin darter is a fish endemic to the
rivers of the Ozark forests, and the Joshua tree is a
plant endemic to the Mojave Desert.
lasting for a very short time
the process of change in the traits of organisms or
populations over time. Evolution, through the process
of natural selection, can lead to the formation of new
refers to a species that no longer exists. Local
extinction occurs when every member of a particular
population has died. Global extinction occurs when
every member of a species has died. The passenger
pigeon and the dodo are examples of globally extinct
the animals that live in a particular area
the plants that live in a particular area
the breaking up of large habitats into smaller, isolated
chunks. Fragmentation is one of the main forms of
habitat destruction, which is the primary reason
biodiversity is in decline.
the science of space and place that brings together
Earth’s physical and human dimensions in the integrated
study of people, places, and environments
the process by which the Earth’s atmosphere is
warming because of the release of “greenhouse gases,”
such as carbon dioxide. These gases are released into
the air from burning gas, oil, coal, wood, and other
resources and trap heat in an action similar to that of
the walls of a greenhouse.
areas of abundant grasses and shrubs with very few
trees, like prairies or meadows. Grasslands can be
found in many places. Large temperate grasslands
occur naturally in central North America (prairies),
southern South America (pampas), central Asia
(steppes), southern Africa (savannas), and Australia.
the trapping of heat in the Earth’s atmosphere by
certain gases such as carbon dioxide, methane, and
nitrous oxide. Some scientists predict that the
temperature and sea level rise associated with global
warming could adversely affect biodiversity.
manure from animals like birds and bats
the area in which an animal, plant, or microorganism
lives and finds the nutrients, water, sunlight, shelter,
living space, and other essentials it needs to survive.
Habitat loss, which includes the destruction,
degradation, and fragmentation of habitats, is the
primary cause of biodiversity loss.
a species that does not naturally occur in an area. Also
called alien, exotic, or non-native species, these
invaders can cause major problems for native plants and
an organism that does not have a backbone
the movement of animals in response to seasonal
changes or changes in the food supply. Examples of
animals that migrate include ruby-throated
hummingbirds, salmon, monarch butterflies, buffalo,
pertaining to a mountainous region
a species that occurs naturally in an area or habitat.
Also called indigenous species.
the process by which genetic traits are passed on to
each successive generation. Over time, natural selection
helps species become better adapted to their
environment. Also known as “survival of the fittest,”
natural selection is the driving force behind the process
chemicals that kill or inhibit the growth of organisms
that people consider undesirable. Fungicides (which kill
fungi), herbicides (which kill plants), and insecticides
(which kill insects) are types of pesticides.
unusual and/or significant occurrences. For example,
the yearly migration of monarch butterflies from central
Mexico into the United States and Canada is a natural
the plant plankton and primary producers in aquatic
a plant species that appears early in the cycle of
vegetation succession. These pioneer plants have
characteristics that particularly suit their role in the early
stages of succession, such as a rapid growth rate and
the ability to produce large amounts of small, easily
hunting, trapping, or fishing illegally
the area in which an organism may travel in its lifetime.
Range also refers to the geographic distribution of a
a region of the Earth that harbors similar groups of
species based on a shared biogeographical history. For
example, while primates are found in many parts of the
world, all monkeys found with prehensile tails are only
found in the Neotropic realm. The Earth is made up of
to return members of a species to their historical range.
This strategy is sometimes used when a species has
become locally extinct or if its population is threatened.
a species that has survived while other related ones
have become extinct. A relict species may be one that
had a wider range but is now found only in particular
areas (like the European white elm tree in western
Siberia), or it may have survived relatively unchanged
from an older period when other kinds of species went
extinct (such as horseshoe crabs).
the repair of ecological damage to an ecosystem so that
it is close to the natural condition prior to a disturbance
and it can function as a normal self-regulating system.
This is done through processes such as chemical
cleanups, revegetation, and the reintroduction of native
pertaining to the banks of a river or other body of fresh
a type of grassland with widely spaced trees and a
blanket of grasses that require a lot of light. Rainfall
usually occurs in the warmer, summer months with a
dry period of between two to eight months. Fires are
typical across savannas during drier months and occur
at intervals from one to 50 years.
Slash and burn
an agricultural system in which farmers periodically
clear land for farming by cutting and burning patches of
forest. Traditionally, patches used for agriculture were
allowed to revert to forests for a number of years
before being replanted, causing minimal impact. Today,
however, intensive slash and burn agriculture damages
many tropical forest ecosystems.
a species that has a narrow ecological niche. For
example, they may be able to live in only one type of
habitat, tolerate only specific environmental conditions,
or eat only a few types of food. The panda is a
specialist species because over 95 percent of its diet
consists only of bamboo.
the process by which one or more populations of a
species become genetically different enough to form a
new species. The process often requires populations to
be isolated for a long period of time.
(1) a group of organisms that have a unique set of
characteristics (like body shape and behavior) that
distinguishes them from other organisms. If they
reproduce, individuals within the same species can
produce fertile offspring. (2) the basic unit of biological
classification. Scientists refer to species using both their
genus and species name. The house cat, for example, is
called Felis catus.
meeting the needs of the present without diminishing
the ability of people, other species, or future generations
a type of coniferous evergreen forest, found in the
subarctic areas of North America and Eurasia. Also
known as a boreal forest
Temperate rain forest
a type of forest found in only a few places around the
world, such as the Pacific temperate rain forest on the
west coast of North America. These forests are often
dominated by conifer trees adapted to wet climates and
Tropical dry forest
a type of forest found near the Equator that has distinct
rainy and dry seasons. Many tropical dry forest plants
are adapted to withstand high temperatures and seasonal
Tropical rain forest
a type of wet forest found near the Equator that harbors
the richest diversity of terrestrial plant and animal
an upward flow of cold, heavy deep-sea water caused
as offshore currents draw away warm surface water.
The deep-sea water of upwellings is generally rich in
areas that, at least periodically, have waterlogged soils
or are covered with a relatively shallow layer of water.
Bogs, freshwater and saltwater marshes, and
freshwater and saltwater swamps are examples of