Evolution Review
Chapter 7
Adaptation and Variation
Adaptation: a structure, behaviour, or physiological process that helps an organism survive and
reproduce in a particular environment.
- Hibernation is an example of physiological adaptation.
Mimicry: a structural adaptation in which a harmless species resembles a harmful species in
coloration or structure.
Variations: differences between individuals which may be structural, functional, or
physiological.
Mutations: a permanent change in the genetic material of an organism; the only source of new
genetic material.
Selective Advantage: a genetic advantage that improves an organism’s chance of survival,
usually in changing environments.
Natural Selection: is the process that results when the characteristics of a population of
organisms change over many generations.
Selective pressure: environmental conditions that select for certain characteristics of
individuals and select against other characteristics.
Fitness: describes the contribution an individual makes to a gene pool of the next generation by
producing offspring that survive long enough to reproduce.
Artificial Selection: selective pressure exerted by humans on populations in order to improve
or modify particular desirable traits.
Biotechnology: the use of technology and organisms to produce useful products.
,Chapter 8
Contributions to the theory of evolution
Aristotle
- Father of ladder of life
- Stated that organisms evolved gradually to more elaborate forms
Buffon
- Believed that the Earth was much older than 6000 years old
- Noticed similarities between humans and apes and suspected they may have a common
ancestor
Hutton
- Members of species vary, and that when the environment changes, those individuals
best adapted to their environment will survive and those who are poorly adapted will
perish
Cuvier
- Father of paleontology
- Found certain layer of rocks had unique species
- Created catastrophism: theory that states that the Earth goes through revolutions
“natural disasters” and unaffected species would re-populate the area.
Lyell
- Rejected Cuvier idea of catastrophism
- Introduced Uniformitarianism: states that the current geological features were created
slow, steady and constant
Lamarck
- Inheritance of acquired characteristics
- Believed that a change of phenotype in an individual can be passed on to the next
generation
Wallace
- Plants and animals evolved to their environment
- Contributed to Darwin’s idea of Survival of the fittest
Darwin
- Survival of the fittest
- He proposed that all life descended from an unknown ancestor
,Sources of evidence for evolution
Fossil record: shows the history of life
Transition fossils: shows intermediate link between now two different species and shared
characteristics common to the separate groups
Biogeography: the study of the past and present geographical distribution of species
population
Anatomies
- Homologous structures
- Analogous structures
- Vestigial structures
Embryology: the study of early development and pre-birth stages.
Chapter 9
Mechanism of Evolution (5 of them)
Mutation
- Mutation randomly introduces new alleles into a population.
- Mutation changes allele frequencies
- Increases variation
- May provide a selective advantage
Gene Flow
- Gene flow occurs between two different interbreeding populations that have different
allele frequencies
- May change the allele frequencies in either or both populations through a flow or
movement of genes
- When two different species interbreed
Non-random mating
● Preferred phenotypes
- Sexual selection: mates are chosen by the presence of a particular phenotype
- Sexual dimorphism: the difference in appearance between males and females
, ● Inbreeding
- Its when closely related individuals mate
- Increases the proportion of homozygous individuals in a population, increasing
the likelihood of harmful recessive traits being expressed.
Genetic Drift
- Change in allele frequency due to chances
● Bottleneck effect
- Occurs when a population quickly reduces in size
● Founder effect
- Occurs when a new colony is started by a few members from the original
population
- Contributes to changes in allele frequencies for the next generation
Natural selection
● Stabilizing selection
- Occurs when the average phenotype has a selective advantage
● Directional selection
- Occurs when an extreme phenotype provides some kind of selective advantage
● Disruptive selection
- Occurs when both extremes of a phenotype have a selective advantage over the
intermediate one.
Chapter 7
Adaptation and Variation
Adaptation: a structure, behaviour, or physiological process that helps an organism survive and
reproduce in a particular environment.
- Hibernation is an example of physiological adaptation.
Mimicry: a structural adaptation in which a harmless species resembles a harmful species in
coloration or structure.
Variations: differences between individuals which may be structural, functional, or
physiological.
Mutations: a permanent change in the genetic material of an organism; the only source of new
genetic material.
Selective Advantage: a genetic advantage that improves an organism’s chance of survival,
usually in changing environments.
Natural Selection: is the process that results when the characteristics of a population of
organisms change over many generations.
Selective pressure: environmental conditions that select for certain characteristics of
individuals and select against other characteristics.
Fitness: describes the contribution an individual makes to a gene pool of the next generation by
producing offspring that survive long enough to reproduce.
Artificial Selection: selective pressure exerted by humans on populations in order to improve
or modify particular desirable traits.
Biotechnology: the use of technology and organisms to produce useful products.
,Chapter 8
Contributions to the theory of evolution
Aristotle
- Father of ladder of life
- Stated that organisms evolved gradually to more elaborate forms
Buffon
- Believed that the Earth was much older than 6000 years old
- Noticed similarities between humans and apes and suspected they may have a common
ancestor
Hutton
- Members of species vary, and that when the environment changes, those individuals
best adapted to their environment will survive and those who are poorly adapted will
perish
Cuvier
- Father of paleontology
- Found certain layer of rocks had unique species
- Created catastrophism: theory that states that the Earth goes through revolutions
“natural disasters” and unaffected species would re-populate the area.
Lyell
- Rejected Cuvier idea of catastrophism
- Introduced Uniformitarianism: states that the current geological features were created
slow, steady and constant
Lamarck
- Inheritance of acquired characteristics
- Believed that a change of phenotype in an individual can be passed on to the next
generation
Wallace
- Plants and animals evolved to their environment
- Contributed to Darwin’s idea of Survival of the fittest
Darwin
- Survival of the fittest
- He proposed that all life descended from an unknown ancestor
,Sources of evidence for evolution
Fossil record: shows the history of life
Transition fossils: shows intermediate link between now two different species and shared
characteristics common to the separate groups
Biogeography: the study of the past and present geographical distribution of species
population
Anatomies
- Homologous structures
- Analogous structures
- Vestigial structures
Embryology: the study of early development and pre-birth stages.
Chapter 9
Mechanism of Evolution (5 of them)
Mutation
- Mutation randomly introduces new alleles into a population.
- Mutation changes allele frequencies
- Increases variation
- May provide a selective advantage
Gene Flow
- Gene flow occurs between two different interbreeding populations that have different
allele frequencies
- May change the allele frequencies in either or both populations through a flow or
movement of genes
- When two different species interbreed
Non-random mating
● Preferred phenotypes
- Sexual selection: mates are chosen by the presence of a particular phenotype
- Sexual dimorphism: the difference in appearance between males and females
, ● Inbreeding
- Its when closely related individuals mate
- Increases the proportion of homozygous individuals in a population, increasing
the likelihood of harmful recessive traits being expressed.
Genetic Drift
- Change in allele frequency due to chances
● Bottleneck effect
- Occurs when a population quickly reduces in size
● Founder effect
- Occurs when a new colony is started by a few members from the original
population
- Contributes to changes in allele frequencies for the next generation
Natural selection
● Stabilizing selection
- Occurs when the average phenotype has a selective advantage
● Directional selection
- Occurs when an extreme phenotype provides some kind of selective advantage
● Disruptive selection
- Occurs when both extremes of a phenotype have a selective advantage over the
intermediate one.
