Textbook - Chapter 5: Ecological Genetics

Question 1

Autotrophs

Answer 1

Organisms that produce organic material from inorganic chemicals and some source of energy

Question 2

Assortive mating

Answer 2

When individuals choose mates nonrandomly with respect to their genotype, or more specifically, select mates based on some phenotypic trait

Question 3

Allele frequency

Answer 3

The proportion of a given allele among all the alleles present at the locus in the population

Question 4

Allele

Answer 4

One or two or more alternative forms of a gene that occupies the same relative position or locus on homologous chromosomes

Question 5

Adaptive radiaiton

Answer 5

Evolution from a common ancestor of divergent forms adapted to distinct ways of life

Question 6

Adaptation

Answer 6

A genetically determined characteristic (behavioral, morphological or physiological) that improves an organism’s ability to survive and reproduce under prevailing environmental conditions.

Question 7

Acclimation

Answer 7

Reversible phenotypic changes in an individual organism in response to changing environmental conditions; a form of phenotypic plasticity

Question 8

Codominance

Answer 8

Occurs when the physical expression of the heterozygous individual is indeterminate between those of the homozygotes. Each allele has specific proportional effect that it contributes to the phenotype

Question 9

Cline

Answer 9

A measurable, gradual change over a geographic region in the average of some phenotypic character, such as size or coloration; or it can be a gradient in genotypic frequency

Question 10

Chromosome

Answer 10

One of a group of threadlike structures of different lengths and sizes in the nuclei of cells of eukaryote organisms

Question 11

Developmental plasticity

Answer 11

Differences in phenotypic traits for a given genotype under different environmental conditions that reflect differences in the allocation of biomass to different tissues (leaves, stem and roots) during the growth and development of the individual plant

Question 12

Directional selection

Answer 12

Selection favoring individuals at one extreme of the phenotype in a population

Question 13

Disruptive selection

Answer 13

Selection in which two extreme phenotypes in the population leave more offspring than the intermediate phenotype, which has lower fitness

Question 14

Dominant allele

Answer 14

An allele that is expressed in either the homozygous or heterozygous state

Question 15

Evolution

Answer 15

Change in gene frequency through time resulting from natural selection and producing cumulative changes in characteristics of a population

Question 16

Ecotype

Answer 16

Subspecies or race adapted to a particular set of environmental conditions

Question 17

Fitness

Answer 17

Genetic contribution by an individual’s descendants to future generations

Question 18

Gene flow

Answer 18

Exchange of genetic material between populations

Question 19

Geographic isolates

Answer 19

Groups of populations that are semi-isolated from one another by some extrinsic barrier; compare subspecies

Question 20

Genotypic frequency

Answer 20

The proportion of various genotypes in a population; compare gene frequency

Question 21

Genotype

Answer 21

Genetic constitution of an organism

Question 22

Genome

Answer 22

The collective term for all the DNA in a cell

Question 23

Gene

Answer 23

Unit material of inheritance; more specifically, a small unit of a DNA molecule, coded for a specific protein to produce one of the many attributes of a species

Question 24

Gene expression

Answer 24

The process of creating proteins through the genetic code in DNA

Question 25

Genetic drift

Answer 25

Random fluctuation in allele frequency over time, due to chance alone without any influence by natural selection; important in small populations

Question 26

Genetic differentiation

Answer 26

When genetic variation occurs among subpopulations of the same species

Question 27

Gene pool

Answer 27

The sum of all the genes of all individuals in a population

Question 28

Hardy-Weinberg Principle

Answer 28

The proposition that genotypic ratios resulting from random mating remain unchanged from one generation to another, provided natural selection, genetic drift and mutation are absent

Question 29

Heterotrophs

Answer 29

Organisms that are unable to manufacture their own food from inorganic materials and thus rely on other organisms, living and dead, as a source of energy and nutrients

Question 30

Heterozygous

Answer 30

Containing two different alleles of a gene, one from each parent, at the corresponding loci of apair of chromosomes

Question 31

Homozygous

Answer 31

Containing two identical alleles of a gene at the corresponding loci of a pair of chromosomes

Question 32

Inbreeding depression

Answer 32

Detrimental effects of inbreeding

Question 33

Inbreeding

Answer 33

Mating among close relatives

Question 34

Locus

Answer 34

Site on a chromosome occupied by a specific gene

Question 35

Mutation

Answer 35

Transmissible changes in the structure of a gene or chromosome

Question 36

Natural selection

Answer 36

Differential success (reproduction and survival) of individuals that results in elimination of maladaptive traits from a population

Question 37

Negative assortative mating

Answer 37

Occurs when mates are phenotypically less similar to each other than expected by chance

Question 38

Norm of reaction

Answer 38

The set of phenotypes expressed by a single genotype across a range of environmental conditions

Question 39

Phenotype

Answer 39

Physical expression of a characteristic of an organism, determined by both genetic constiution and environment

Question 40

Phenotypic plasticity

Answer 40

Ability to change form under different environmental conditions

Question 41

Positive assortative mating

Answer 41

Occurs when maters are phenotypically more similar to each other than expected by chance

Question 42

Primary producer

Answer 42

Green plant or chemosynthetic bacterium that converts light or chemical energy into organismal tissue

Question 43

Quantitative Trait

Answer 43

Phenotypic characteristics that have a continuous distribution

Question 44

Qualitative traits

Answer 44

Phenotypic characteristics that fall into a limited number of discrete categories

Question 45

Recessive allele

Answer 45

Applies to an allele whose phenotypic effect is expressed in the homozygous state and masked in the presence of an allele in organisms to heterozygous for that gene

Question 46

Subspecies

Answer 46

Geographical unit of a species population distinguishable by morphological behavioral or physiological characteristics

Question 47

Stabilizing selection

Answer 47

Selection favoring the middle in the distribution of phenotypes

Question 48

Selective agent

Answer 48

The environmental cause of fitness differences among organisms with difference phenotypes

Question 49

Secondary producers

Answer 49

Organisms that derive energy from consuming plant of animal tissue and breaking down assimilated carbon compounds

Question 50

Target of selection

Answer 50

The phenotypic trait that natural selection acts directly upon