Bio exam 1 - Evolution

hypothesis

A suggested explanation, usually based on an observation

hypothesis must be

testable and falsifiable

manipulation

independent variable

measurable

dependent variable

control

a baseline standard or unchanged setup used for comparison to prove that an experiment's results come from the tested variable rather than outside factors

line graph

displays data points connected by straight line segments to show how a value changes over a continuous interval or time

bar graph

a visual chart that uses rectangular bars to compare different groups or categories of data

scatter plot

uses dots to show the relationship between two different numerical variables

proximate explanation

how it works

ultimate explanation

why behind a trait or behavior

“just a theory”

a broad explanation of some aspect of the natural world that is sustained by a large body of evidence

evolution

change in genetic frequencies in a population over generations

population

group of organisms of the same species that live in the same geographic area and interbreed

community

all living things that interact

evolution happens at the population level

not individual, species do not evolve

same species if the same species can …

breed to produce fertile offspring

2 key elements of evolution

heritability and variation

heritability

estimate of how much variation in a trait among individuals in a specific population is due to genetic differences rather than environmental factors

variation

the differences in physical traits, behaviors, or genetic makeup between individuals of the same species

DNA, deoxyribonucleic acid

molecules that carries heritable information

genotype

an organisms unique genetic makeup

phenotype

physical expression of a trait

polymer

large molecule made of many smaller, repeating units

gene

sequence of DNA that codes for a specific trait

alleles

versions of a gene

meiosis

process of cell division that produces genetics

gametes

sperm and egg

molecules

a group of two or more atoms stuck together by chemical bonds

organelle

specialized structures inside a cell that performs a specific job

cell

smallest basic unit of life that makes up all living things

tissue

a group of similar cells that work together to perform a specific job

organ

a group of different tissues that work together to do a specific job in a living thing

organ system

a group of organs that work together to do a major job for the body

population

group of organisms of the same species that live in the same geographic area and interbreed

community

all living things that interact

ecology

how living organisms interact with each other and their environment

biosphere

global zone on Earth where all life exists, covering all living organisms and the areas they inhabit

chromosome

a thread like structure made of DNA tightly wrapped around proteins, acting as an instruction manual for the body

chromatid

one of the two identical halves of a copied chromosome

independent assortment

the alleles for different traits are sorted into sperm and egg cells independently of one another

meiosis

process of cell division that produces gametes

homozygous

two identical versions of a specific gene

heterozygous

having two different versions of that gene

gene linking

the tendency of genes that are located close together on the same chromosome to be inherited together during sexual reproduction

pleiotropy

a genetic phenomenon where a single gene influences two or more distinct and often seemingly unrelated phenotypic traits

epistasis

genetic interaction where the effect of one gene is masked, inhibited, or suppressed by the expression of a completely different gene

ontogeny

an organisms phenotype changes throughout the course of its life

phenotypic plasticity

a change in the phenotype of a single organisms in response to its environment

evolution by natural selection

some organisms are more likely to survive and reproduce than others

evolutionary fitness

measures an organisms relative success at surviving, finding mates, reproducing, and passing its genes or alleles on to the next generation

directional selection

stabilizing selection

disruptive selection

sexual selection

differences in reproductive success caused by competition over mates, and related to expression of a trait

anisogamy

form of sexual reproduction where two fusing gametes differ in size, shape, or mortality

choosy sex

sex that is selective when picking a mate

competitive sex

sex that fights or competes with members of the same species for access to that mate

Bateman’s principle

the variation in reproductive success is typically much greater in males than in females within a species

intersexual selection

the competition between members of the same sex for access to mates

intersexual selection

the choice of mates by members of one sex based on specific traits in the opposite sex

mate choice

the process by which the choosy sex assesses the sexual signals of the competitive sex to choose a mate

preference

ranking of sexual signals

choosiness

the amount of effort a female will put into sampling mates

adaptive traits

help and individual survive function and thrive in their environment

maladaptive traits

interfere with daily functioning, provide only temporary relief and cause long term harm

gene flow

movement of alleles between two populations

mutations

a permanent change in the DNA sequence of an organism or virus

point mutation

1 nucleotide is replaced with a different nucleotide during replication

deletion

a nucleotide is deleted out of a sequence

insertion

an additional nucleotide is added a second time

duplication

section of DNA is copied a second time

inversion

a segment of DNA is flipped and inserted backwards into its original position

chrosome fusion

two chromosomes join together as one

Aneuploidy

entire chromosomes are duplicated or lost

genome duplication

all of the DNA in the cell is copied

Hardy Weinberg Equilibrium

describes a population where there is no
evolution happening

gene pool

the complete set of all genes, including different alleles or genetic variants, present in a reproducing population or species

genetic drift

random events than can be
significant at small population sizes and over long
time periods

Selection

Differential breeding success + Nonrandom mating (i.e. sexual selection)

phylogeny

a visual representation of the evolutionary history of populations, genes, or species

homologous traits

traits two or more species share with a common
ancestor

derived trait

a new trait not shared with a common ancestor

analogous traits

traits that have a similar function but are derived at two
different times points

convergent evolution

the process where unrelated species independently evolve similar physical traits or behaviors because they live in similar environments or face the same survival challenges

monophyletic group

organisms and a common ancestor that share a trait

polyphyletic group

organisms that share a trait that is not shared with a common ancestor

paraphyletic group

a group that shares traits with each other and their common ancestors, but do not include other subgroups

principle of parsimony

when constructing evolutionary lineages- we assume that the tree with the fewest evolutionary changes is the most plausible

species

evolutionarily independent population or group of populations

biological species concept

species consist of populations that are reproductively isolated from each other (no interbreeding or no viable offspring —> no gene flow)

prezygotic isolation

occurs when individuals of different species are prevented from mating.

postzygotic isolation

occurs when individuals from different populations do mate, but the hybrid offspring produced have low fitness and do not survive or produce offspring

morphological species concept

populations that are consistently morphologically distinct from each other

phylogenetic species concept

populations that are the smallest monophyletic group on a phylogenetic tree

phylogenetic species concept

defines a species as the smallest group of organisms that share a common ancestor and can be distinguished from other such groups on a evolutionary tree

speciation

lineage splitting through separation of gene pools

isolation

reduction in gene flow

geographic isolation

dispersal and colonization + vicariance