Biology Comprehensive Exam

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benthic zone

Back 1

The bottom of a body of water including the surface and shallow subsurface layers of sediment.

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biome

Back 2

A large-scale terrestrial biological community shaped by the regional climate, soil, and disturbance patterns where it is found, usually classified by the growth form of the dominant plants.

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biosphere

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The highest level of biological organization, consisting of all living organisms on Earth plus the environments in which they live; located between the lithosphere and the troposphere.

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convergence

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The evolution of similar growth forms among distantly related species in response to similar selection pressures.

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desertification

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Degradation of formerly productive land in arid regions resulting in loss of plant cover and acceleration of soil erosion.

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land use change

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The alteration of terrestrial surface, including vegetation and land forms, by human activities such as agriculture, forestry, and mining.

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littoral zone

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The nearshore zone of a lake where the photic zone reaches to the bottom.

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macrophyte

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A rooted or floating aquatic vascular plant.

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nekton

Back 9

Swimming organisms capable of overcoming water currents

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pelagic zone

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The open water column of a lake or ocean.

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permafrost

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A subsurface soil layer that remains frozen year-round for at least 3 years

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photic zone

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A subsurface soil layer that remains frozen year-round for at least 3 years

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phytoplankton

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Photosynthetic plankton

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plankton

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Small, often microscopic organisms that live suspended in water; although many plankton are mobile, none can swim strongly enough to overcome water currents.

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savanna

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A vegetation type dominated by grasses with intermixed trees and shrubs

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acclimatization

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An organism's adjustment of its physiology, morphology, or behavior to lessen the effect of an environmental change and minimize the associated stress

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adaptation

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A physiological, morphological, or behavioral trait with an underlying genetic basis that enhances the survival and reproduction of its bearers in their environment.

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avoidance

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A response to stressful environmental conditions that lessens their effect through some behavior or physiological activity that minimizes an organism's exposure to the stress.

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ecotype

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A population with adaptations to unique local environmental conditions.

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ectotherm

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An animal that regulates its body temperature primarily through energy exchange with its external environment

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adaptive evolution

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A process of evolutionary change in which traits that confer survival or reproductive advantages tend to increase in frequency in a population over time.

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adaptive radiation

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An event in which a group of organisms gives rise to many new species that expand into new habitats or new ecological roles in a relatively short time.

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directional selection

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Selection that favors individuals with one extreme of a heritable phenotypic trait

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disruptive selection

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Selection that favors individuals with a phenotype at either extreme over those with an intermediate phenotype.

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stabilizing selection

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(1) Change in allele frequencies in a population over time. (2) Descent with modification; the process by which organisms gradually accumulate differences from their ancestors.

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gene flow

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The transfer of alleles from one population to another via the movement of individuals or gametes.

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genetic drift

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A process in which chance events determine which alleles are passed from one generation to the next, thereby causing allele frequencies to fluctuate randomly over time; the effects of genetic drift are most pronounced in small populations.

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natural selection

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The process by which individuals with certain heritable characteristics tend to survive and reproduce more successfully than other individuals because of those characteristics.

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K-selection

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In the r- and K-selection continuum used for classifying life history strategies, the selection pressure for slower rates of increase faced by organisms that live in environments where population densities are high (at or near the carrying capacity, K).

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phenotypic plasticity

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The ability of a single genotype to produce different phenotypes under different environmental conditions.

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r-selection

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In the r- and K-selection continuum used for classifying life history strategies, the selection pressure for high population growth rates faced by organisms that live in environments where population densities are usually low.

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absolute population size

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The actual number of individuals in a population.

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abundance

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The number of individuals in a species that are found in a given area; abundance is often measured by population size or population density.

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ecological niche

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The physical and biological conditions that a species needs to grow, survive, and reproduce.

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population

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A group of individuals of the same species that live within a particular area and interact with one another.

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Explain the differences between animal, fungal, plant, and bacterial cells

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Cellulose - plants and fungal (although different cellulose)
Chloroplasts - plants only
Chitin - fungi and animals
Membrane bound organelles - fungi, plants, animals
LPS - bacteria

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Chlorophyll A

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Main photosynthetic pigment in all organisms except bacteria

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Can plants respire?

Back 38

YES

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thylakoids

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Chlorophyll and cartenoid pigments are located in these disk like structures
The light dependent reaction occurs here and produces ATP to the light independent reactions

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relative species abundance

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how common or rare a species is relative to other species in a defined community
Calculated by dividing the number of species from one group by total number of species from all groups

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competitive exclusion principle

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a proposition which states that two species competing for the same resources cannot coexist if other ecological factors are constant. When one species has even the slightest advantage or edge over another, then the one with the advantage will dominate in the long term. One of the two competitors will always overcome the other, leading to either the extinction of this competitor or an evolutionary or behavioral shift towards a different ecological niche.

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intermediate disturbance hypothesis

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states that local species diversity is maximized when ecological disturbance is neither too rare nor too frequent

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What happens to a community when disturbance is too low?

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More competitive species will push less competitive to extinction (unless adaptation can occur). Invasive species can be a good example

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What happens to a community when disturbance is too high?

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Only extremely resistance species can survive dramatically decreasing the diversity

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keystone species & examples

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a species that has a proportionally larger effect on it's ecosystem
i.e. sea otters & kelp forests