Biology Unit 3

Front 1

Genotype

Back 1

The genetic constitution, or set of alleles, of an individual organism

Front 2

Phenotype

Back 2

the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment

Front 3

Genetic Drift

Back 3

A process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next. Effects of ________ are most pronounced in small populations.

Front 4

Gene Flow

Back 4

In population genetics, _________ (also known as gene migration) is the transfer of alleles or genes from one population to another. Migration into or out of a population may be responsible for a marked change in allele frequencies (the proportion of members carrying a particular variant of a gene).

Front 5

Artificial Selection

Back 5

The breeding of plants and animals to produce desirable traits. Organisms with the desired traits, such as size or taste, are artificially mated or cross-pollinated with organisms with similar desired traits.

Front 6

Convergent Evolution

Back 6

The evolution of similar features in independent evolutionary lineages.

Front 7

Coevolution

Back 7

The joint evolution of two interacting species, each in response to selection imposed by the other.

Front 8

Reproductive Isolation

Back 8

The existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring.

Front 9

Allopatric Speciation

Back 9

a fancy name for speciation by geographic isolation. In this mode of speciation, something extrinsic to the organisms prevents two or more groups from mating with each other regularly, eventually causing that lineage to speciate.

Front 10

Sympatric Speciation

Back 10

The formation of new species in populations that live in the same geographic area.

Front 11

Cryptic Coloration

Back 11

Coloration that allows an organism to match its background and hence become less vulnerable to predation or recognition by prey.

Front 12

Aposematic Coloration

Back 12

(of the coloration of certain distasteful or

poisonous animals) characterized by bright conspicuous markings, which predators

recognize and learn to avoid; warning

Front 13

Mimicry

Back 13

the close external resemblance of an organism, the mimic, to a different organism, the model, such that the mimic benefits from themistaken identity, as seeming to be unpalatable or harmful.

Front 14

Energetic Hypothesis

Back 14

The concept that the length of a food chain is limited by the ineffieciency of energy transfer along the chain.

Front 15

Character Displacement

Back 15

refers to the phenomenon where differences among similar species whose distributions overlap geographically are accentuated in regions where the species co-occur, but are minimized or lost where the species' distributions do not overlap.

Front 16

Shared Derived Character

Back 16

An evolutionary novelty that is unique to a particular clade.

Front 17

Shared Ancestral Character

Back 17

A character, shared by members of a particular clade, that originated in an ancestor that is not a member of that clade.

Front 18

Homoplasy (similar structure)

Back 18

A similar (analogous) structure or molecular sequence that has evolved independently in two species.

Front 19

Taxa

Back 19

a taxonomic group of any rank, such as a species, family, or class

Front 20

Clade

Back 20

a group of organisms believed to have evolved from a common ancestor. A _______ is equivalent to a monophyletic group.

Front 21

Molecular Clock

Back 21

A method for estimating the time required for a given amount of evolutionary change, based on the observation that some regions of genomes evolve at constant rates.

Front 22

Abiotic Environment

Back 22

In biology and ecology, abiotic components or, abiotic factors, are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and phenomena associated with them underpin all biology.

Front 23

Evapotranspiration

Back 23

The total evapotranspiration of water from an ecosystem, including water transpired by plants and evaporated from a landscape, usually measured in millimeters and estimated for a year.

Front 24

Symbiotic

Back 24

In biology, refers to any diverse organisms that live together, but in this case, the relationship is not necessarily beneficial to both. Parasites, for example, have a _________ relationship with their hosts, but only the parasite benefits.

Front 25

Mutualism

Back 25

the doctrine that mutual dependence is necessary to social well-being.

Front 26

Parasitism

Back 26

non-mutual symbiotic relationship between species, where one species, the parasite, benefits at the expense of the other, the host.

Front 27

Commensalism

Back 27

an association between two organisms in which one benefits and the other derives neither benefit nor harm.

Front 28

Keystone Predator

Back 28

An essential predator in an ecosystem. Without the __________, the herbivorous prey would explode in numbers, wipe out the dominant plants, and dramatically alter the character of the ecosystem.

Front 29

Logistic Growth Model

Back 29

In ____________ (1) over time the population size increases until the population size equals the carrying capacity and then the population size remains at the carrying capacity and (2) populations initially grow slowly and over time the population growth rate increases until it reaches a maximum (at N = 1/2k).

Front 30

K-selection

Back 30

Selection for life history traits that are sensitive to population density; also called density-dependent selection.

Front 31

r-selection

Back 31

Selection for life history traits that maximize reproductive success in uncrowded environments; also called density-independent selection.

Front 32

r (the rate of population change)

Back 32

The difference between the birth and death rate.

Front 33

Carrying Capacity

Back 33

the number of people, other living organisms, or crops that a region can support without environmental degradation, represented by the symbol K.

Front 34

Demographic Transition

Back 34

refers to the transition from high birth and death rates to low birth and death rates.

Front 35

Territoriality

Back 35

A behavior in which an animal defends a bounded physical space against encroachment by other individuals, usually of its own species.