BIOL 112 EXAM 1

fixed allele

fixed allele

An allele that is the only variant that exists for a gene in a population.

Gene Pool

All the alleles of all the genes in a population.

Allele

Two or more alterative forms of a gene.

Genotypic Frequency

Proportion of each genotype in the population. %AA, %Aa and %aa

Allelic Frequency

% of each allele in the population %A allele and %a allele.

Germ Line Mutation

Only mutations in cells can be passed onto the offspring.

Phenotype

The product of an inherited genotype and many environemlental influences.

Genotype

The genetic constitution of an organism.

Genetic Variation

Differences among individuals in the composition of their genes.

Allopolyploidy

Resulting from viable mating between two distinct species. Source of extra chromosomes different species. Need 2 reproductive acts before the ________ is formed to make it viable and fertile.

Polyploidy

A cell or organism that has an extra set or sets of chromosomes.

Descent with Modification

A phrase Darwin used in proposing that Earths many species are descendants of ancestral species that were different from the present day species.

Natural Selection

"Survivial of the Fittest" The reproduction of individuals with favorable genetic traits that survive environmental change because of those traits leading to evolutionary change --> leads to greater adaptation of the population to its local environment.

Microevolution

A change in allele frequencies in a population over generations.

Population Genetics

The study of what changes the allele frequencies in populations.

Genetic Drift

Genetic Frequency changes due to random events. some individuals will have more offspring than others not due to an advantage. Often occurs in small populations like sampling errors in statistics.

Gene Flow

Alleles move in/out of a population.

Adaptive Evolution

evolutionary changes in an organism that make it suitable to its habitat

Hardy Weinberg Equilibrium

If a large population reproduces sexually at random, then the genetic frequencies should not change in next generation (remains in equilibrium)

Punnet Square

A square diagram that is used to predict the genotypes of a particular cross.

How does H-W let us detect microevolution?

If the actual rations do not equal the expected H-W rations, then the population is evolving.

Founder Effect

a few founders start new isolated population

founder gene pool differs from original source small population size leads to more drift better alleles may be lost.

Bottleneck Effect

An event drastically cuts population size, gene pool of survivors is random; some alleles are lost.

requirements for HWE

No mutations population should be large mating is random No natural Selection

Relative Fitness

Relative to other individuals in the population. best reproductive success. The contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals.

Directional selection

When the environment changes, selects the phenotypes at one end of the spectrum of all existing variation

Diversifying selection

Intermediates are less fit than extremes, maintains diversity, increases genetic variance

Stabilizing Selection

Intermediates types are more fit than extremes, decreases genetic variance.

Frequency-Dependent Selection

favors phenotypes that are either common (positive) or rare (negative)

Sexual Selection

A process in which same sex individuals with certain inherited characteristics are more likely to obtain mates than those who do not have those characteristics.

Sexual Dimorphism

A difference in secondary sexual characteristics between males and females of the same species. Ex: Size, color, orientation, or behavior

Intrasexual Selection

Individuals of one sex compete directly for mates of the opposite sex.

Intersexual Selection

Called mate choice, individuals of one sex (ususally the females) are choosy in selecting their mates from the other sex.

Phylogeny

The evolutionary history of a species and its relationship to other species.

Rooted Phylogenetic tree

Single Lineage (at base) represents common ancestor.

Unrooted Phylogenetic Tree

Show relationships but not a common ancestor. Illustrate the relatedness of the leaf nodes without making assumptions about ancestry.

Carl Woese, Otto Kandler, and Mark Wheelis

Who Proposed the three domain of life?

Eukarya

Cells do contain a nucleus. Include the plants, animals, fungi, and protists.

Is multicellular cell wall: varies between plants and fungi, animals do not have cell wall. Has a nucleus has membrane bound organelles.

Archaea

Not multicellular Has a cell way without peptidoglycan Does not have a nucleus Does not have membrane bound organelles.

Bacteria

Not multicellular, Has a call wall with peptidoglycan, does not have a nucleus, Dose not have membrane bound organelles.

Root

Indicates that an ancestral lineage gave rise to all organisms on the tree.

Branch Point

Indicates where two lineages diverged. (nodes)

Basal Taxa

A lineage that evolved early and remains unbranched.

Sister Taxa

When two lineages stem from the same branch point

Polytomy

A branch with more than two lineages

Systematics

study of phylogenetic relationships

Taxa

The tips of the branches and represents the youngest lineages on the tree.

Clade

a grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor.

Cladistic Analysis

Grouping organisms in a way that reflects their evolutionary relationship

Monophyletic Group

Consists of an ancestral species and all of its descendants

Paraphyletic Group

Consist of an ancestral species and some, but not all, of its descendants.

Polyphyletic group

Includes distantly related species but does not include their most recent common ancestor.

Allopatric Speciation

geographic separation of populations from a parent species and subsequent evolution

convergent evolution

where similar traits evolve independently but the species do not share a common ancestry

vestigial structures

unused structures without function

endemic species

species that can only be found in one place

speciation

the formation of 2 species from 1 species

sympatric speciation

involves speciation occurring within a parent species remaining in one location

two categories of allopatric process

dispersal - when a few members of a species move to a new geographical area
vicariance - when a natural situation arises to physically divide organisms

adaptive radiation

when many adaptations evolve from a single point of origin causing species to radiate into several new ones

aneuploidy

when chromosomes pair separate and the end cell product has too many or too few individual chromosomes

Autopolyploidy

occurs when organisms have more than two sets of chromosomes from the same species.

two groups of reproductive isolation

prezygotic barrier - a mechanism that blocks reproduction from taking place (Temporal, habitat, behavior, and gametic isolation)

postzygotic barrier - occurs after zygote formation (hybrid unviability, hybrid sterility, hybrid breakdown)

temporal isolation

difference in breeding schedules

habitat isolation

populations of a species move or are moved to a habitat and take up residence in a place that no longer overlaps with the same species’ other population

behavioral isolation

occurs when the presence or absence of a specific behavior prevents reproduction

gametic behavior

differences in gamete cells prevent fertilization from taking place

hybrid inviability

hybrid individuals cannot form normally in the womb and do not survive past the embryonic stages

hybrid zone

an area when 2 closely related species continue to interact and reproduce

reinforcement hybrid zone

species continue to diverge until hybridization no longer can continue

fusion hybrid zone

the reproductive barrier weakens until the 2 species become one

stability hybrid zone

fit hybrid continue to be produced

gradual speciation model

species diverge gradually over time in small steps

punctuated equilibrium

a species undergoes change quickly from the parent species and remain unchanged for a large period of time afterwards

hybrid sterility

different species can produce a viable offspring but that offspring cannot reproduce

Hybrid breakdown

second generation hybrids are feeble or sterile

analogous structures

features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature

homologous structures

structures derived from a common ancestor, the same overall layout even if the bones’ shapes and size differs

divergent evolution

two groups of the same species evolve different traits within those groups in order to accommodate for differing environmental social pressures

Taxonomy Hierarchy

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

Aristotle

Placed traits on the scale nature, believing species were unchanging (ladder of nature)

Carl Linnaeus

Orderly nested classification system (taxonomy) was created through binomial naming. Grouped species in closely related species, genus, family, order, class, phylum, kingdom, domain.

James Hutton

Father of Geology, Earth's geological features are a result of gradual mechanisms and that is a slow continuous process. Ex: canyon being carved by a river.

Charles Lyell

Uniformitarianism expanded Hutton's Ideas. Same geologic processes in past as today.

Erasmus Darwin

first person to propose the theory of evolution but did not come up with natural selection, taught that life evolved from one common ancestor and gradual complex character sare introduces as life evolves. Wrote ideas that form minute slowly acquired complexity over time.

Jean Baptiste Lamarck

Linked evolution to adaptation, extinct species have been replaced by descendants with new features. These adaptations helped them survive in the environment. Theory of inheritance of acquired characteristics through use and disuse. Acquired characteristics cannot be inherited.

Lamarckism

all the physical changes occurring in an individual during its lifetime are inherited by its offspring

Charles Darwin

Drew a Phylogenetic tree
Theory of natural selection, and evidence of evolution through fossils.

Alfred Wallace

independent of Darwin, realized evolution from his findings at the Malay Archipelago, both presented scientific papers on natural selection together before the Linnean Society in 1858

Gene Pool

Sum of all alleles in a population.