Biomes Study Guide: Bio Lab H
Chapter 3
Ch 3 vocab: ammonia, biogeochemical cycle, nitrogen fixation,
denitrification, limiting nutrient, ecosystems, keystone species, food chain,
food web, trophic level, detritivore, carnivore, omnivore, decomposer,
heterotroph, autotroph, nitrogen cycle, ecological pyramids: energy,
biomass, and number.
Energy flows through an ecosystem in one direction, from the sun or
inorganic compounds to autotrophs (producers), and then to various
heterotrophs (consumers). Sunlight is the main energy source; some unusual
organisms can convert chemical energy into living matter without needing
sunlight.
Only about 10 percent of the energy available within one trophic level is
transferred to organisms at the next trophic level.
Vocab: food chain, food web, trophic level, ecological pyramid, biomass.
3-3 Unlike the one-way flow of energy, matter is recycled within and
between ecosystems.
For example, all organisms require nitrogen to make amino acids which are
used to make proteins. Nitrogen fixation is the process in which nitrogen gas
from the air is converted by bacteria in the roots of plants to ammonia.
Bacteria in the soil and producers use ammonia and organic compounds to
make proteins. Consumers then eat these producers and reuse the nitrogen
to make their own proteins.
Chapter 4
Ch 4 vocab
Temperate, tropical, biotic factor, abiotic factor, habitat, niche, resource,
competitive exclusion principle, predation, symbiosis, mutualism,
commensalisms, parasitism, succession: primary and secondary, pioneer
species; deciduous, permafrost, disturbance. New organisms move in as old
organisms die out, causing further change.
4-2
Biotic and abiotic factors determine the productivity of the ecosystem.
Community interactions such as competition, predation, and various forms
of symbiosis can powerfully affect an ecosystem. Ecosystems are
constantly changing in response to natural and human disturbance.
4-3
Abiotic factors primarily determine the biome. Know your biome (project)
from this list of major biomes: tropical rainforest, tropical deciduous forest,
savanna, hot desert, temperate woodland, temperate grassland, chaparral,
taiga, tundra.
Chapter 5
Ch 5 vocab
Population, community, carrying capacity, population density, immigration,
emigration, geographical distribution, exponential growth, logistic growth,
density-dependent limiting factors.
5-1
Three important characteristics of a population are its geographic
distribution, density, and growth rate. Three factors affect population size:
the number of births, the number of deaths, and the number of individuals
that enter or leave the population. Under ideal conditions the population will
grow exponentially. As resources are used up, the growth becomes logistic.
5-2
Density-independent limiting factors include competition, predation,
parasitism, and disease. They affect large, dense populations. They do not
affect all populations in the same way.