Chapter 5

Question 1

– a mechanism that explains how the diversity of organisms inhabiting our world have acquired the features seemingly designed to enable them to survive and reproduce

Answer 1

Theory of Natural Selection

Question 2

the differential success (survival and reproduction) of individuals within the population that results from their interaction with their environment

Answer 2

natural selection

Question 3

Natural selection is a product of two conditions (as outlined by Darwin). What is the two conditions?

Answer 3

(1) that variation occurs among individuals within a population in some “heritable” characteristic, and
(2) that this variation results in differences among individuals in their survival and reproduction as a result of their interaction with the environment

Question 4

measured by the proportionate contribution it makes to future generations of an individual

Answer 4

fitness

Question 5

changes in the properties of populations of organisms over the course of generations which the result of natural selection

Answer 5

evolution

Question 6

any heritable behavioral, morphological, or physiological trait of an organism that has evolved over a period of time by the process of natural selection such that it maintains or increases the fitness (long-term reproductive success) of an organism under a given set of environmental conditions

Answer 6

adaptation

Question 7

represent the characteristics (traits) that enable an organism to survive, grow, and reproduce under the prevailing environmental conditions

Answer 7

adaptation

Question 8

structural adaptation

Answer 8

• teeth
• body coverings for defense
• movement
• fish snout: superior, terminal, inferior
• caudal fin: lunate, forked, truncate, rounded, continuous
• colouration: counter shading, mottled, mimicry, stripe

Question 9

This adaptation involves some part of an animal’s body.

Answer 9

structural adaptation

Question 10

A form of camouflage where an animal’s underside is lighter and its back is darker, helping it blend with both sky and ground or water.

Answer 10

Counter shading

Question 11

Behavioral adaptations

Answer 11

type of fish migration
hibernation
being nocturnal

Question 12

explains this survival and shows how species can change over time. For example, certain traits of adaptations involving color, camouflage, food gathering (beaks and claws) and other physical traits, sensory abilities or behaviors enhance the survival of a species.

Answer 12

natural selection

Question 13

natural selection examples

Answer 13

o Monarch butterflies
o Finches from Galapagos Archipelago

Question 14

the Units of Inheritance

Answer 14

genes

Question 15

form the informational units of the DNA molecule

Answer 15

genes

Question 16

genetic material that codes for a functional product

Answer 16

genes

Question 17

alternate forms of a gene; (Greek) allelomorphs = “different form”

Answer 17

alleles

Question 18

process by which DNA is used in the synthesis of products such as protein

Answer 18

gene expression

Question 19

collectively all of the DNA in a cell

Answer 19

genome

Question 20

microscopic, threadlike bodies by which genes are arranged in linear order

Answer 20

chromosomes

Question 21

position occupied by a gene on the chromosome; (Latin) locus = place

Answer 21

locus

Question 22

two copies of each type of chromosome in each individual cell of a most multicellular organisms

Answer 22

homologous chromosomes

Question 23

pair of alleles present at a given locus of an individual

Answer 23

genotype

Question 24

set of alleles

Answer 24

genotype

Question 25

two main categories of genotypes:

Answer 25

homozygous heterozygous

Question 26

two copies of the gene are the same

Answer 26

homozygous

Question 27

two alleles at the locus are different

Answer 27

heterozygous

Question 28

the Physical Expression of the Genotype

Answer 28

Phenotype

Question 29

outward appearance of an organism for a given characteristic

Answer 29

Phenotype

Question 30

the external, observable expression of the genotype

Answer 30

Phenotype

Question 31

the allele that is expressed in which one allele masks the expression of the other

Answer 31

dominant allele

Question 32

the allele that is masked

Answer 32

recessive allele

Question 33

the allele if the physical expression of the heterozygous individual is intermediate between those of the homozygotes

Answer 33

incomplete dominance

Question 34

phenotypic characteristics that fall into a limited number of discrete categories

Answer 34

qualitative traits

Question 35

Two reasons why the continuous distribution of most phenotypic traits occurs:

Answer 35

1. more than one gene locus affecting them 2. environment

Question 36

continuous distribution of traits, such as height or weight

Answer 36

quantitative traits

Question 37

ability of a genotype to give rise to different phenotypic expressions under different environmental conditions

Answer 37

phenotypic plasticity

Question 38

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

Answer 38

norm of reaction

Question 39

the phenotypic plasticity occurs during the growth and development of the individual and represents an irreversible characteristic

Answer 39

Developmental plasticity

Question 40

reversible phenotypic changes in an individual organism in response to changing environmental conditions

Answer 40

Acclimation

Question 41

What is the development of the low-light plant vs the high-light plant?

Answer 41

* low light: more photosynthetic leaf area, thin leaves, less biomass, few branches * high light: narrow leaves, more biomass, many branches

Question 42

phenotypic trait that selection acts directly upon

Answer 42

target of selection

Question 43

genetic variation occurs among subpopulations of the same species

Answer 43

genetic differentiation

Question 44

the sum of genetic information (alleles) across all individuals in the population

Answer 44

gene pool

Question 45

represents the total genetic variation within a population

Answer 45

gene pool

Question 46

the environmental cause of fitness differences among organisms with different phenotypes

Answer 46

selective agent

Question 47

three general types of natural selection:

Answer 47

directional selection stabilizing selection disruptive selection

Question 48

type of natural selection, in which the mean value of the trait is shifted toward one extreme over another

Answer 48

directional selection

Question 49

natural selection may favor individuals near the population mean at the expense of the two extremes

Answer 49

stabilizing selection

Question 50

occurs when members of a population are subject to different selection pressures

Answer 50

disruptive selection

Question 51

can be defined as a change in the mean or variance of a phenotypic trait across generations as a result of changes in allele frequencies

Answer 51

phenotypic evolution

Question 52

product of natural selection

Answer 52

adaptations