AP Biology - Evolution Terms

The Origin of Species

Book written by Charles Darwin that presented a body of evidence that the diversity of life arose by common descent through a branching pattern of evolution; argued that species evolved from ancestral species and natural selection was a mechanism for evolution

Plato (first)

Ancient Greek philosopher; believed that evolution is counterproductive since world is made of ideal organisms perfectly adapted to environment and orderly - not accidents of evolution

Aristotle (second)

Ancient Greek philosopher; believed that species arranged in a “fixed scale of natural perfection” – each organism placed on particular rung of ladder of complexity

Natural theology (third)

Old Testament of Bible → belief that God created plants and animals designed for a particular purpose without misfits (mutations) or extinctions, which are cruel, haphazard and wasteful; “survival of the fittest” contradicts biblical doctrine of love and unselfish sacrifice

Linneaus (fourth)

Created classification system called taxonomy and binomial nomenclature; the hierarchy of his system was evidence that species evolved from common ancestors

Kingdom, phylum, class, order, family, genus, species

Linnaean Ranks in order

Taxonomy

The branch of science concerned with classification

Binomial nomenclature

The system of nomenclature in which two terms are used to denote a species of living organism, the first one indicating the genus and the second the specific epithet

Hutton (fifth)

Developed the Principle of Gradualism

Principle of Gradualism

Belief that profound change (in landforms) is cumulative product of slow but continuous process; (ex) mountains and oceans formed over long period of time through gradual processes

Lyell (sixth)

Developed the Theory of Uniformitarianism

Theory of Uniformitarianism

Theory that geological processes that alter the Earth are uniform through time; rates & effects balance out over time; slow, subtle processes working for long time cause major change → Earth is OLD!

Malthus (seventh)

British economist that developed the Principle of Population; observed that the human race would be likely to overproduce if the population size was not kept under control; population growth will stop or reverse with disease, famine, war or calamity

Principle of Population

Belief that human population will inevitably outgrow its capacity to produce food

Lamarck (eighth)

Developed one of the earliest models that attempted to explain evolution; believed that organisms evolve to greater complexity and perfection to better suit their environment; believed in the Idea of Use and Disuse and Inheritance of Acquired Characteristics

Idea of Use and Disuse

Theory that parts used to survive in environment grow bigger & stronger; parts not used to deteriorate (ex) a giraffe’s neck grows longer to reach the trees

Inheritance of Acquired Characteristics

Theory that modifications are passed onto offspring

Cuvier (ninth)

French zoologist who developed paleontology but rejected evolution; developed the Theory of Catastrophism; observed fossils of extinct animals → gaps in the fossil succession are mass extinction events; his work was incorporated into Darwin’s theory of natural selection & survival of the fittest

Theory of Catastrophism

Idea that natural history has been punctuated by periodic catastrophic events which has caused mass extinctions that are repopulated by immigrating species and altered that way life developed and rocks were deposited

Fossils

Show succession of organisms on Earth over time; lay the groundwork for Darwin’s idea

Alfred Wallace (tenth)

British naturalist that co-developed theory of natural selection with Darwin; helped develop the Theory of Evolution; realized that if an animal has a beneficial trait that allows it to survive & breed more successfully, it will leave more offspring behind → trait becomes more common in following generations; motivated Darwin to publish the Origin of Species

Charles Darwin (eleventh)

English naturalist that developed the Theory of Evolution and Natural Selection

HMS Beagle

Ship that Darwin sailed on while observing and collecting specimens

Descent with modification

The idea that species change over time, give rise to new species, and share a common ancestor; explains both life’s unity and diversity; explains how traits change over time

Descendants, common ancestor, modification

Darwin proposed that organisms are related by being ___ of a ___ ___, with ___ among the descendants

Natural selection

The process that drives evolution; differential success in reproduction results in adaptation of organisms to environment over long periods of time

Survival of the fittest

Phrase that describes who succeeds in natural selection

Overproduction, variation, selection, adaptation

Steps of the Theory of Evolution by Natural Selection (hint: there are four)

All species have huge reproduction potential, most populations are stable, limited natural resources, varied individuals within a population, most variation is heritable

Observations of natural selection and adaptation (hint: AMLVM)

Artificial selection

The process of selection conducted under human direction; idea that contributed to Darwin’s theory that selection is a force in evolution; shows huge changes in populations over time (ex) breeding of domesticating plants and animals for desired traits

Evolutionary adaptation

Camouflage is an example of…

Biogeography, fossil record, comparative anatomy, comparative embryology, molecular biology

Techniques used to validate evolution (hint: BFCCM)

Biogeography

Geographical distribution of species

Convergent evolution

Organisms that appear similar and related due to similar environments but have evolved independently from separate ancestors

Fossil record

Technique of validating evolution; fossil ages agree with evolution and can show evolutionary missing links

Comparative anatomy

Technique of validating evolution; confirms that evolution is a remodeling process

Homologous structures

Anatomical signs of descent with modification; structures that are phenotypically and genetically similar due to common ancestry but have different functions due to differing environments

Vestigial organs

Rudimentary homologous structures with marginal or no functions

Analogous structures

Similarities between organisms due to similar environmental pressures that produce similar adaptations despite different evolutionary lineages; look alike but do not have a common ancestor

Comparative embryology

Technique of validating evolution; closely related organisms go through similar stages in embryonic development (ex) all vertebrate embryos with gill pouches & post-anal tails

Molecular biology

Technique of validating evolution; the more alike the genes & proteins of 2 species, the closer is their evolutionary relationship

Adaptations

Modification of an organisms or its parts that makes it more fit for existence under the conditions of its environment

Transitional fossil

Fossilized organism that displays characteristics of both an ancestral species and its evolved descendant species

Strata

Another word for rock layers

Amber, trace, mold, petrified, carbon, cast, compression

Types of fossils (hint: ATMPCCC)

Cladogram

A “family tree” that displays the relationship between the number of differences and relatedness of different species

Pharyngeal pouches

Pockets that form in the embryo between the pharyngeal arches; produce tissues necessary for hearing, calcium homeostasis, and immune response

Post-anal tail

A posterior elongation of the body, extending beyond the anus; contains skeletal elements and muscles, which provide a source of locomotion in aquatic species; in some terrestrial vertebrates, it also helps with balance, courting, and signaling when danger is near

Evolution

The process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth

Microevolution

Change in allele frequencies in a population over generations

Natural selection, genetic drift, gene flow

Three mechanisms that alter gene frequency directly and cause evolution (microevolution)? (hint: NGG)

Genetic variation

Differences among individuals in composition of genes (or DNA); can be contrasting (red or purple flowers) or along a continuum (human height)

Formation of new alleles, altering gene number or position, rapid reproduction, sexual reproduction

Sources of genetic variation (hint: FARS)

Mutation

Change in DNA

Formation of new alleles by mutation

Source of genetic variation; new mutation transmitted in gametes can immediately change gene pool of population; leads to evolution because it is an original source of genetic variation → serves as raw material for natural selection

Heterozygous protection

Harmful mutations in recessive alleles are masked

Diploidy

2 sets of chromosomes; prevents elimination of recessive alleles via selection → doesn’t impact phenotype in heterozygote

Neutral variation

When a mutation does not confer either selective advantage or disadvantage due to noncoding DNA regions, redundancy/wobble effect, or changes in amino acids don’t change protein structure or function

Non-coding DNA regions, redundancy/wobble effect, no change in protein structure or function

What causes neutral variation? (hint: NRN)

Duplication of genes, transposable DNA elements

Key potential sources of variation when altering gene number or position (hint: DT)

Rapid reproduction

Source of genetic variation; low mutation rates in bacteria & viruses but because of many generations, mutations cause genetic variation (ex) HIV

Sexual reproduction

Source of genetic variation; genetic variation of population results from unique combination of alleles that each individual receives from parents

Crossing over, independent assortment, random fertilization

Mechanisms of variation in sexual reproduction (hint: CIR)

Population

Group of individuals of the same species that live in the same area and interbreed and produce fertile offspring

Gene pool

A population's genetic make up; all the different alleles in all the individuals in a population

Hardy-Weinberg equilibrium

Describes the gene pool of a non-evolving population

Allele frequencies, constant, generations, segregation, recombination, evolution

The Hardy-Weinberg Equilibrium states that ___ ___ will remain ___ over ___ unless acted upon by agents other than Mendelian ___ and ___ of alleles; we can compare this non-evolving population with another to see if ___ is happening

Frequency of the dominant allele

What is p?

Frequency of the recessive allele

What is q?

p² + 2pq + q^² = 1

Hardy-Weinberg equation for phenotype frequencies

Frequency of getting homozygous dominant

What is p²?

Frequency of getting homozygous recessive

What is q²?

Frequency of getting a heterozygote

What is 2pq?

p + q = 1

Hardy-Weinberg equation for allele frequencies

Very large population size, no migrations, no net mutations, random mating, no natural selection

What 5 conditions must the populations at Hardy-Weinberg Equilibrium satisfy to remain non-evolving? (hint: VNNRN)

Adaptive radiation

An event in which a lineage rapidly diversifies, with the newly formed lineages evolving different adaptations

Adaptive radiation

Natural selection causes…

Genetic drift

Unpredictable changes in allele frequencies due to chance events when populations are small

Smaller, deviation, generation, genetic variation, alleles

The ___ the sample, more chance of ___ from one ___ to next → can lead to a loss of ___ ___ and loss of ___ due to death or lack of reproduction

Founder effect, bottleneck effect

Two scenarios that result in genetic drift (hint: FB)

Founder effect

New population started by few individuals that do not represent the gene pool of the larger source population (ex) human populations that started from a small group of colonists or a few members of a population are blown by a storm to a new island

Bottleneck effect

Number of individuals in a large population is drastically reduced by a sudden change in the environment

Alleles, over-represented, under-represented, eliminated, conservation biology

In the bottleneck effect, ___ may be ___ or ___ among survivors or ___ altogether; important concept in ___ ___ of endangered species

Gene flow

Genetic exchange due to migration of fertile individuals or gametes between populations → increases the frequency of particular alleles in next generation; reduces differences between populations (ex) bee carrying pollen from one flower population to another

Relative fitness

A measure of biological fitness wherein the reproductive rate of a genotype or a phenotype is relative to the maximum reproductive rate of other genotypes or phenotypes in a given population; the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals (ex) a person who has four children has a greater ___ than a person who only has one child

Directional, disruptive, stabilizing

Modes of selection (hint: DDS)

Directional selection

Shifts frequency curve for a phenotypic character in one direction by favoring what had been rare individuals; common during periods of environmental change or when members of a population migrate to a new habitat with different environmental conditions

Disruptive selection

Environmental conditions favor individuals at both extremes of phenotypic range over intermediate phenotypes

Stabilizing selection

Favors intermediate variants and acts against extreme phenotypes; reduces variation & maintains predominant phenotypes (ex) human birth weight

Sexual selection

Individuals with certain inherited characteristics that are more likely to obtain mates

Sexual dimorphism

Difference in secondary sexual characteristics in males and females (ex) size, coloration, enlarged or exaggerated features, adornments, behaviors

Intrasexual selection

Direct competition of one sex (usually males) for mates of the opposite sex; dominance may be determined by direct physical battle or ritualized displays

Intersexual selection/mate choice

Individuals of one sex (usually females) select their mates of the opposite sex; some traits that attract females are not adaptive—may be disadvantageous; female choices perpetuate certain alleles

Balancing selection

Natural selection process that helps maintain genetic diversity in populations; selective force that keeps different alleles in a population's gene pool at higher frequencies than would be expected from genetic drift alone

Heterozygote advantage, frequency-dependent selection

Two mechanisms of balancing selection (hint: HF)

Heterozygote advantage

Individuals heterozygous at a particular locus have greater survivorship & reproductive success than homozygotes; multiple alleles maintained at locus by natural selection; promotes balanced polymorphism (ex) sickle cell anemia carriers are resistant to malaria

Frequency-dependent selection

The fitness of a phenotype declines if it becomes too common in the population; selections favors whichever phenotype is less common in a population; promotes balanced polymorphisms

Evolution is limited by historical constraints, adaptations are often compromises, not all evolution is adaptive, selection can only edit existing variations

If natural selection, then why aren’t we perfect? (hint: EANS)

Speciation

Origin of new species; process by which one species splits into two or more species

Macroevolution

Origin of new taxonomic groups