BIO 1114H Exam 1

Exam Date: 9/25

a good hypothesis is:

testable and falsifiable

null hypothesis

what should be observed when the hypothesis isn’t correct

control

checks for factors that may affect experimental outcome

prediction

a statement of what will happen if a hypothesis is correct given a specific set of circumstancesand is typically based on prior knowledge or theory.

confounding variables

factors that would affect results if not controlled for or considered

observational experiment

a type of experiment where the independent variable varies naturally

certainty is indicated by:

a low p value and variability

proximate cause

immediate causes and mechanisms that underlie a trait and how it works

ultimate cause

forces that have shaped the trait overtime that has evolved to benefit survival and reproduction

pattern

a statement that summarizes a series of observations about the natural world, how things are in nature

process

a mechanism that produces the pattern

Plato’s theory of evolution

every organism was created by God, any variation was around a “perfect essence” that was unchanging

Aristotle + scale of nature

typological thinking on a ladder/scale based on complexity of organisms, species are fixed types

Lamarck + evolution as a change through time

simple organisms exist at the bottom of the scale and as to move up they evolve, goal-oriented, experiences create acquired traits

Darwin + Wallace evolution by natural selection

species are static and change overtime

population thinking

variation is the key to understanding the nature of species

typological thinking vs population thinking

typological - numerous copies of one type of organism exist

population - individuals vary within a population

MAKE CARDS FOR EVOLUTIONARY EVIDENCE

AND EXAMPLES FOR THINGS + GO THRU NITTY GRITTY

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Law of Succession

fossils appear in an order that resembles current species

transitional feature

a trait in a fossil species that’s intermediate between those of ancestral and derived species

vestigial trait

a reduced or incompletely developed structure that has little or no function but is similar to functioning structures in related species

abiotic factors

non-living components that cause changes to populations

examples of abiotic factors

rise in temperature, drop in sea level

biotic factors

living components that cause changes to populations

examples of biotic factors

the arrival of a new parasite, the extinction of a predator

homology

the study of likeness

what are the three levels of homology?

genetic, developmental, structural

genetic homology

similarities in DNA, RNA, amino acid sequences

developmental homology

similarities in developmental structures and processes

structural homology

similarities in adult form (morphology)s

speciation

new species being formed from preexisting species

internal consistency

the observation that data from independent sources agree in supporting predictions made by a theory

artificial selection

choosing certain individuals with desirable traits to reproduce

Darwin’s Postulates

1) variation exists among individuals that make up a population

2) some trait differences are heritable

3) survival and reproductive success are highly variable

4) individuals that survive and reproduce is not random, some traits are more favorable

what traits are not heritable?

purely plastic traits

natural selection

the process where organisms with more suitable traits are more likely to survive, reproduce, and pass those traits to their offspring

evolutionary fitness

the ability of an individual to produce surviving and fertile offspring relative to ability of other individualsa

adaptation

a heritable trait that increases the fitness of an individual in a particular environment relative to individuals lacking the trait

selection

a passive process where differential reproduction occurs as a result of heritable variation

behavior

response to a stimulus

evolution

change in allele frequency in a population overtime

frequency

how common an allele is in a population relative to other alleles in a population

genetic differentiation

genetic variation among local populations

fitness tradeoffs

compromise between two traits that can’t be optimized simultaneously

Degrees of Genetic Differentiation:

1) cline

2) ecotype

3) geographic isolates

cline

not distinctly different populations, measurable and gradual change over a geographic region

ecotype

distinctly different populations with some gene flow, population adapted to its unique local conditions

geographic isolates

extrinsic barrier prevents the free flow of genes among populations

hybridization

the interbreeding of genetically distinct populations

fitness is determined by:

how reproductively successful an individual is

can evolution happen in a generation?

no

any change in allele frequency is…

natural selection

directional selection

reduces genetic variation in a population, favored alleles approach 1.0, disadvantageous alleles approach 0.0

stabalizing selection

reduces genetic variation in a population, favors individuals near the population mean

disruptive selection

increases genetic variation, favors individuals near the extremes

balancing selection

maintains genetic variation, when no phenotype has a distinct advantage

heterozygote advantage

heterozygotes have higher fitness than homozygous

frequency-dependent selection

rare phenotype is selected for, leading to balancing selection

inbreeding

mating between relatives

self-fertilization

an organism’s own gametes unite to produce offspring

inbreeding depression

decline in average fitness that takes place when homozygosity increases

sexual selection

an organism actively chooses a certain mate based on physical/behavioral traits

genetic drift

a change in allele frequencies in a population that is due to chance

founder effect

the change in allele frequency when a new group of individuals immigrate to a new geographic area

population bottlenecks

when a large population experiences a sudden reduction in size

genetic bottlenecks

a sudden reduction in diversity of alleles of a population

gene flow

the movement of alleles between populations

point mutation

a change in a single base pair in DNA

chromosome-level mutation

a change in number or composition of chromosomes

lateral gene transfer

transfer of genetic information from one species to another