AP Bio Unit 7

pattern of evolution

data, species, and life evolving over time

process of evolution

mechanisms that cause the observed pattern of change in evolution

aristotle

guy that viewed species as fixed and unchanging

scala naturae

aristotle’s creating where life-forms are arranged on a scale or ladder of increasing complexity, and this is their permanent spot

linnaeus

guy that created the two-part format for evolution

nested, creation

linnaeus’ two-part format for evolution was the ____ classification system and the idea that resemblances among species was due to the pattern of ______

paleontology

the study of fossils

cuvier, catastrophic

guy that opposed the idea of evolution and said each boundary between strata was a ______ and sudden event

hutton

guy that said evolution happens by slow continuous processes (darwin agreed)

true

lamarck’s hypothesis of evolution is not ____

Lamarck’s

____ hypothesis included Use and Disuse and Inheritance of Acquired Characteristics

use and disuse

lamarck’s idea that body parts used a lot get stronger, while others deteriorate

inheritance of acquired characteristics

lamarck’s idea that an organism has an innate drive to become more complex and passes this to its offspring

adaptations

inherited characteristics of organisms that enhance their survival and reproduction in specific environments

natural selection

process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates because of those inherited traits

descent with modification

the thought that evolution is a process in which descent and modification can be observed

descent

shared ancestry resulting in shared characteristics

modification

the accumulation of differences

artificial selection

humans have modified species over many generations by selecting and breeding individuals that posses desired traits

individuals

in natural selection, the ____ do not evolve

drug-resistant bacteria

bacteria that develops resistance to a drug over time, because certain individuals survive the antibiotic treatments and reproduce

homology

similarity resulting from common ancestry

homologous structures

underlying skeletons of different mammals that represent variations on a structural theme present in their common ancestor

vestigial structures

remnants of features that served a function in the organism’s ancestors but not anymore

molecular homologies

homologies that go beyond a shared genetic code

convergent evolution

independent evolution of similar features in different lineages (sugar gliders and flying squirrels evolved from different ancestors but adapted to similar environments in similar ways)

analogy

resemblance between species because of convergent evolution (different ancestry but similar function)

biogeography

the scientific study of geographic distributions of species

endemic

plant and animal species that are found nowhere else in the world

phylogeny

the evolutionary history of a species or group of species

binomial nomenclature

the way biologists refer to organisms by their Latin scientific names

taxon

named taxonomic unit at any level

species, genus, family, order, class, phylum, kingdom, domain

hierarchical classification order

phylogenetic tree

evolutionary history of a group of organisms in a branching tree diagram

branch point

the common ancestor of the 2 lineages diverging from it in a phylogenetic tree

sister taxa

groups of organisms that share an immediate common ancestor not shared by any other group

rooted tree

a branch point represents the most recent common ancestor in this type of phylogenetic tree

basal taxon

a lineage diverges from group members early in history

coincidental, redundant

molecular homologies can be unreliable because matches can be _______ and the codon chart is _____

homoplasy

character shared by a set of species but not present in their common ancestor

cladistics

an approach where common ancestry is the primary criterion used to classify organisms

clades

groups of species that include an ancestral species and all of its descendants

monophyletic

this clade includes an ancestral species and all its descendants

paraphyletic

this clade includes an ancestral species and some, but not all, descendants

polyphyletic

this clade includes distantly related species but not their most recent common ancestor

shared ancestral character

a character that originated in an ancestor of the taxon

shared derived character

an evolutionary novelty that is unique to a clade (can also be a loss of a character)

outgroup

a species or group of species from an evolutionary lineage that is closely related to, but not part of, the group of species we are studying

ingroup

the group of species being studied

branch length

in a phylogenetic tree, this can reflect the number of changes that have taken place in a particular DNA sequence in that lineage

maximum parsimony

a principle that says we should first investigate the simplest explanation that is consistent with the facts (fewest evolutionary events of fewest base changes)

occam’s razor

other name for maximum parsimony

hypothesis

phylogenetic trees are best used as only a ____

molecular clock

an approach for measuring the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constant rates

time

with a molecular clock, the number of nucleotide substitutions is proportional to the ____ elapsed since the branches diverged

microevolution

the change in allele frequencies in a population over generations

genetic variation

differences among individuals in the composition of their genes or other DNA sequences (heritable: height - nonheritable: muscles)

neutral variation

variation that causes no advantages or disadvantages

phenotype

new alleles are formed by mutation →new allele →impact on ______

chromosomal changes

gene number and position can be altered by ________ _______: deletion, disrupting, or rearranging loci OR duplication of genes due to errors in miosis

rapid reproduction

mutations can quickly generate genetic variation in prokaryote populations (drug-resistant)

sexual reproduction

reproduction that creates genetic variation from unique combinations of alleles that each individual receives from its parents

gene pool

all copies of every type of allele at every locus in all population members

p

variable for the frequency of one allele

q

variable for the frequency of the other allele

1

p + q = ?

hardy-weinberg equilibrium

a population that is not evolving, and allele and genotype frequencies remain constant from generation to generation

random, selection, large, flow

conditions for hardy-weinberg equilibrium include no mutations, _____ mating, no natural _______, _____ population size, no gene ______

genetic drift

chance events can cause allele frequencies to fluctuate unpredictably from generation to generation (especially in small populations)

founder effect

when a few individuals become isolated from a larger population and establish a new population with a different gene pool (ex: because of a storm)

bottleneck effect

a severe drop in population size and certain alleles become overrepresented, underrepresented, or absent, leading to low genetic variation

gene flow

allele transfer in and out of a population due to movement of fertile individuals or their gametes

relative fitness

the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals

directional selection

conditions favor individuals exhibiting one extreme of a phenotypic range, therefore shifting a population’s frequency curve for the phenotypic character in one direction or the other (population migrates/environment changes)

disruptive selection

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

stabilizing selection

selection that acts against both extreme phenotypes and favors intermediate variants

recessive, heterozygous

unfavorable ______ alleles persist in diploid organisms because they are hidden from selection when in _____ individuals

balancing selection

selection itself may preserve variation at some loci, thus maintaining two or more phenotypic forms in a population

heterozygote advantage

individuals who are heterozygous at a particular locus have greater fitness than others

frequency-dependent selection

the fitness of a phenotype depends on how common it is in the population

sexual selection

individuals with certain inherited characteristics are more likely than other individuals of the same sex to obtain mates (peacocks with bigger feathers get females)

sexual dimorphism

the difference in secondary sexual characteristics between males and females of the same species (size, color, behavior)

speciation

process by which one species splits into 2 species

species

a group of populations whose members have the potential to interbreed in nature, and produce viable, fertile, offspring

reproductive isolation

the existence of biological factors or barriers that impede members of 2 species from interbreeding and producing viable, fertile, offspring

hybrids

offspring that results from an interspecific mating

prezygotic barriers

barriers that block fertilization from occuring (stop mating attempts or hinder fertilization)

postzygotic barriers

barriers that contribute to reproductive isolation after the hybrid zygote has formed (developmental errors)

distinct

some species are _____ but gene flow still occurs between them (grolar bears)

morphological species concept

concept that distinguishes species by structural features/body shape and relies on subjective criteria

ecological species concept

concept that defines a species in terms of its ecological niche, or how its members interact with their environment (includes asexual species)

allopatric speciation

gene flow is interrupted when a population is divided into geographically isolated subpopulations (canyon, river divides them)

sympatric speciation

speciation occurs in populations that live in the same geographic area (ex: caused by polyploidy)

polyploidy

an accident during cell division that results in extra sets of chromosomes

autopolyploid

an individual that has more than 2 chromosome sets that are all derived from a single species

allopolyploid

a sterile hybrid that became a fertile polyploid

hybrid zone

a region in which members of different species meet and mate, producing offspring of mixed ancestry (the zone can move)

reinforcement

one thing that could happen to hybrid zone - STRENGTHENING: the formation of unfit hybrids is reduced and reproductive barriers are enforced

fusion

one thing that could happen to hybrid zone - WEAKENING: so much gene flow occurs that reproductive barriers weaken further and the gene pools of the 2 species become increasingly alike (2 species become 1)

Stability

one thing that could happen to hybrid zone - CONTINUED: hybrid zone is stable and hybrids continue to be produced