Chapter 12: Glossary

Deserts biomes

________ characterized by extremely low precipitation, coarse sandy soil, and cactus and other low- water adapted plants.

Grasslands a biome

________ characterized by moderate precipitation, rich soil, and sod- forming grasses.

Decomposers

________- organisms that consume dead plant and animal material- the process of decomposition returns nutrients to the environment.

Estuary

________- the part of the wide lower course of a river where its current is met by the tides.

Evolution

________- change in the genetic composition of a population during successive generations as a result of natural selection acting on the genetic variation among individuals and resulting in the development of new species.

Ecotones

________- regions where different biomes overlap.

Detritivores

________- organisms that derive energy from consuming nonliving organic matter, such as dead animals or fallen leaves.

symbiotic relationship

Commensalism- ________ in which one organism benefits while the other is neither helped nor hurt.

Gross Primary Productivity

________- the amount of sugar that the plants produce in photosynthesis.

Deciduous forest a biome

________ characterized by adequate precipitation, rich soil with high organic content, and hardwood trees.

Autotrophs

________- producers; organisms that can produce their own organic compounds from inorganic compounds; they use energy from the Sun or from the oxidation of inorganic substances.

Evaporation

________- conversion of a liquid into a gas (vapor)

Denitrification

________- the process by which specialized bacteria (mostly anaerobic bacteria) convert ammonia to NO3, NO2, and N2, which are released back into the atmosphere.

Biomes ecosystems

________ based on land.

biological density

Edge effect- the condition in which there is greater species diversity and ________ at ecosystem boundaries than there is in the heart of ecological communities.

cold temperatures

Abyssal zone- the deepest region of the ocean, marked by extremely ________ and low levels of dissolved oxygen, but high levels of nutrients because of the decaying plant and animal matter that sinks down from the zones above.

Biodiversity

________- the number and variety of organisms found within a specified geographic region, or ecosystem, or the variability among living organisms, including the variability within and between species and within and between ecosystems.

Generalist

________- a species that has a broad niche, is highly adaptable, and can live in varied habitats.

Euphotic zone

________- the photic, upper layers of ocean water; the ________ is the warmest region of ocean water and has the highest levels of dissolved oxygen eutrophication- warm water becoming overly enriched with minerals and nutrients to the point that excessive growth of algae and other phytoplankton occurs (an algal bloom)

Assimilation

________- the process in which plants absorb ammonium (NH3), ammonia ions (NH4+), and nitrate ions (NO3) through their roots.

Chaparral

________- scrub forest or shrubland; a biome characterized by moderate precipitation, shallow or infertile soil, small trees with large, hard evergreen leaves, and spiny shrubs.

Gene

________ pool- the total genetic makeup of a population.

Genetic drift

________- the random fluctuations in the frequency of the appearance of a gene in a small, isolated population, presumably owing to chance, rather than natural selection.

autotrophic bacteria

Chemotrophs- ________ that use chemosynthesis to produce energy in anaerobic environments.

Extinction

________- the death of an entire species; permanent inactivity.

Evolutionary fitness

________- the better- adaptedness of individual organisms for their environment that allows them to live and reproduce, ensuring that their genes are part of their populations next generation.

Ecozones

________ (ecoregions)- smaller regions within ecosystems that share similar physical features.

Consumers

________- organisms that must obtain food energy from secondary sources, for example, by eating plant or animal matter.

Aquatic life

________ zones- ecosystems in aqueous environments.

Biological extinction true extermination of a species no individuals of this species

________ are left on the planet.

Epilimnion

________- the uppermost and thus the most oxygenated layer of freshwater.

Climax community

________- a stable, mature community in a successive series that has reached equilibrium after having evolved through stages and adapted to its environment.

Biogeochemical cycles

________- the complex cycles through which nutrients such as carbon, oxygen, nitrogen, phosphorus, sulfur, and water move through the environment.

Bathyal zone

________- the middle region of the ocean, characterized by less density of organisms because it does not receive enough light to support photosynthesis.

Ammonification

________- the production of ammonia or ammonium compounds in the decomposition of organic matter, especially through the action of bacteria.

Coral reef

________- an erosion- resistant marine ridge or mound consisting chiefly of compacted coral together with algal material and biochemically deposited magnesium and calcium carbonates.

Benthic zone

________- the surface and sub- surface layers of the river,- lake,- pond,- or streambed, characterized by very low temperatures and low oxygen levels.

Biotic living

________ or derived from living things.

Coastal zone

________- ocean zone consisting of the ocean water closest to land, usually defined as between the shore and the end of the continental shelf (the edge of the tectonic plate); characterized by abundant sunlight and oxygen.

Competitive exclusion

________- the process that occurs when two different species in a region compete and the better adapted species wins coniferous forest (taiga)- a biome characterized by moderate precipitation, acidic soil, and coniferous trees.

Competition

________- the relationship that exists when two individuals- of the same species or of different species- compete for resources in the same environment.

Cultural services

________- use of nature for science and education, therapeutic and recreational uses, and spiritual and cultural uses.

Ecosystem

________- a system of interconnected elements: a community of living organisms and its environment.

Habitat

________ fragmentation- when the size of an organisms natural habitat is reduced, or when development occurs that isolates a(n) ________ or part of one.

Energy pyramid the structure

________ obtained if we organize the amount of energy contained in producers and consumers in an ecosystem by kilocalories per square meter, from largest to smallest.

ecosystem-a system of interconnected elements

a community of living organisms and its environment