Part I.: Ecology

BIO 311D homepage Basic definitions
  Facts to remember
  Problem solving and formulas
Diversity Patterns in Space

Basic definitions

ecosystem: a group of species that are interconnected by energy and mineral flow.

primary productivity: the amount of chemical energy bound by primary producers per unit area per unit time. Its common units are: cal/m2/year, kcal/ha/year, Joule/m2/year.

biomass: the amount of dry weight of living organisms per unit area. Its units are g/m2, kg/m2, kg/ha.

handling time: the time it takes from capture of food item by a foraging organism to digestion.

reproductive effort: amount of energy diverted into the production of reproductive structures and offspring by an organism.

succession: the predictable series of species replacements in a community over time.

oligotrophic: water that has low nutrient and high oxygen content.

eutrophic: "opposite of oligotrophic"

biomagnification: the increase in the concentration of certain substances that can not be metabolized from one trophic level to the next.

greenhouse-effect: the trapping of heat in the atmosphere by certain (so-called "greenhouse") gases.

global warming: the increase of the global average temperature on Earth.

community: a gruop of coexisting interacting populations.

niche: the multidimensional resource space that a population occupies.

population: a group of interbreeding individuals.

carrying capacity: the maximum density of a population that its environment can support.

density-dependent factor: a regulating factor whose impact on the population changes with population density. (Note that here by impact we mean the proportion of affected individuals in the population)

doubling time: the time a population takes to double in size.

fertility: the average number of offspring per female during their lifetime.

net reproductive rate: number of females in (t+1)th generation per number of females in the tth generation.
The average number of female offspring per females per generation.

cohort: a group of individuals of a population born at the same time.

age-specific survivorship: the proportion of a cohort surviving from birth to age x.

age-specific fecundity: the average number of female offspring of females at age x.

generation time: the average time that passes between the birth of a female and the birth of her offspring.

life expectancy: the average time an individual of age x can expect to live in the future.

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Facts to remember

Total number of species described: 1.5 million (rough estimate)
Arthropods (insects, spiders, mites and crustaceans) make up about half of it.

primary succession is simultaneous with soil development -- no soil initially.

secondary succession: on already existing soil -- much faster

climax: the endpoint community of succession which is typical of the regional climate (I.e. in western Kansas it is mixed grassland, in New England it is broadleaved forest, etc.) -- see biomes above

Minerals are recycled in an ecosystem.

Energy can not be recycled. It is eventually lost, as respiratory heat.

The most productive ecosystems are swamps, estuaries and tropical rainforests.

A cornfield is very efficient in capturing incoming light energy. It captures about 1.2 %.

From one trophic level to the next only about 1/3 of the energy is transferred.

Only substances that are not metabolized can be biomagnified.

The 95 % breakdown time for DDT is10 years.

Greenhouse gases are: CO2, methane, water vapor, nitrous oxides and CFC's.

The expected global temperature increase due to global warming by 2050 is 4 degrees.

The first major bubonic plague epidemic occurred in 1347-50 in Europe.

Viral diseases: Influenza, AIDS
Bacterial diseases: Cholera, Leprosy, Pneumonia, Lyme-disease, Chicken pox

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Problem solving and formulas

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