Unit 6- evolution Flashcards
~27 questions
what is evolution?
change over time
natural selection
individuals with certain traits are more likely to survive and reproduce than others
-mechanism of descent with modification
taxonomy
branch of biology concerning identifying, naming and classifying species
species definition
pop’s can interbreed and produce fertile offspring with eachother
what ship did Darwin travel on after quitting med school
HMS beagle - collected thousands of specimens while traveling the world
where did Darwin make his most profound discoveries?
Galapagos islands
what book did Darwin write?
The Origin of Species where he explains his Theory of Evolution
theory def
widely accepted explanation that is broader than a hypo
hierarchical classification (specific to least specific)
species —> genus –> family —> order –> class –>phylum –> kingdom –>domain
fossil record
ordered sequence of fossils by age
- marking the passage of geological time
fossil def
imprints/remains of organisms that lived in the past
-studied by paleontologists
what can fossils be preserved by?
resin, ice, bogs, layered sediment at the bottom of water bodies
how is relative age determined in a fossil?
radiometric decay of FIRST layer of desigment
homology
similarity resulting from common ancestry
vestigial structures
remnants of features that performed important functions in an individual’s ancestor
examples of vestigial structures
embryonic similarities
goosebumps
wisdom teeth
artificial selection
selective breeding of plants/animals to promote occurrence of desirable traits
do individuals or populations evolve?
Populations - individual variation DOES NOT result in evolution, only gen. variation does
how does natural selection occur?
a random advantageous mutation occurs that helps individual survive to reproduce –> trait increases every generation —> entire species has evolved to have trait
what three things increase gen. variation?
random fertilization
crossing over
law of indep. assortment
population def
a group of individuals of the same species that live in the same area
gene pool
frequency of alleles
mechanism of microevolution
genetic drift
who was the first to suggest species evolved from interactions with environment?
Jean-Baptiste Lamarck
analogous structures
similar structures that evolve independently (not bc of common ancestry)
Lamarck vs. Darwin
Lamarck thought that individuals evolved throughout their lifetime while Darwin believed in descent with modification gradually
fitness
an indv’s ability to survive and pass on its gen. info to offspring
-reproductive evolutionary sucess
genetic variation def
differences in DNA/traits among diff pops of same species
adaptation def
process in which species becomes fitted to their environment
survival of the fittest
organisms that are the most ‘fit’ or ‘adapted’ to their environment have higher chance of surviving and reproducing
genetic drift
a RANDOM change in the gene pool of a pop
bottleneck effect
gen. drift due to drastic reduction in pop. size which decrease gen. variability
-some alleles lost
-overrepresenation of alleles
how long will gen. drift go on for in bottleneck effect?
gen. drift will continue until pop. is large enough where it becomes insignificant
does the founder effect happen with small/large pops?
occurs when small number of indvs are separated from parent pop.
-reduces gen. variation?
gene flow
gen. drift where a pop. may gain or lose alleles by gen. exchange with another pop
-might cause pop’ s to merge
-caused by immigration/emigration
which famous philosopher held the idea that species are fixed?
Aristotle
Who developed a concept identical to Darwin?
Wallace
Who came up with gradualism principal/theory that earth was VERY old and sculpted by graudal geologic processes?
Lyell (scottish geologist)
sexual selection
indv’s with certain (attractive) traits are more likely to mate than others
sexual dimorphism def
secondary sexual traits that help in attract
e.g. colorful adornments, feathers, etc
directional selection
individuals with allele at ONE end of trait are favored
e.g. antibiotic resistance
disruptive
opposite ends of trait are favored, creating contrast
e.g. big can scare off others, small can hide, medium size would die
stablizing
individuals with intermediate trait are favored
e.g, newborn human birth weight
speciation def
process in which one species splits into 2+ species
comparative embyrology
comparison of structures that appear during fetal development of diff. species to determine relatedness
hardy-weinberg equilibrium conditions
- no mutations
- no net movement
- large population
- random mating
- all alleles are equally viable (no natural selection)
molecular evidence of evolution
common. gen code shared by all organisms allows comparisons
+ shows that all life once had a common ancestor
coevolution
2 organisms evolving simultaneously to benefit each other
e.g. trumpet flower and humming bird
reproductive barriers function
prevent gen info from being passed on between different species
prezygotic barriers
prevent fertilized egg from forming
prezygotic barrier types
- temporal isolation
- habitat isolation
- mechanical isolation
- gametic isolation
post-zygote barriers function
operate If organisms do interbreed and a hybrid zygote is formed
post-zygote: reduced hybrid viability/vitality
hybrid dies before maturity
post-zygote: reduced hybrid fertility
hybrids become adults but are sterile
post-zygote: hybrid breakdown
first gen. hybrids survive and reproduce but THEIR children are weak/sterile
3 domains of life
Archaea, Bacteria, Eukarya
allopatric speciation
occurs as a result of geographic isolation
sympatric speciation
origin of new species without geographic isolation
-polyploid
polyploid def
accidentally creates a new species bc of cell division errors —> two complete sets of chromosomes and can no longer mate with parent pop.
-usually happens in plants
convergent evolution
two unrelated species develop similar traits bc they live in sim. environments
divergent evolution
individuals in one species acquire enough gen. variations to speciate
p^2 + 2pq + q^2 = ?
1
examples of macroevolution
gen drift- bottleneck, founder, gene flow
q represents what?
recessive allele
p represents what?
dominant allele
pq represents what?
heterozygotes
p + q = ?
1 / 100%
there are 40/100 indv’s in a pop. with blue eyes, a recessive allele
what is the frequency of the heterozygotes?
0.4% = p
0.6% = q
ans: 0.24%
what was early earth’s atmosphere like?
C02, H20, CO, H2, N2, NH3, ammonia, H2S, CH4
-No free 02 present
what was early/primordial earth like?
originally cold, but heat built up with radioactive decay, gases, hot springs, volcanoes, or collisions
4 conditions necessary for chemical evolution to occur
- absence of free O2 (would have broken down organic molecules)
- energy (storms, volcanoes, UV radiation, etc)
- chemicals
- time
Urey and Miller’s experiment
designed an apparatus that simulated conditions on early earth
—> saw that these conditions produced aa’s and early building blocks
4 stage hypo for origin of life
- synthesis of small organic molecules from abiotic chemicals
- link monomers —> polymers
- self-replicating molecules (RNA) for inheritance
- formation of pre-cells (molecular packages with SOME properties of life)
—> simple cells
what comes first, simple or complex molecules?
simple-
e.g. unicellular —> multicellular
anaerobic —> aerobic
asexual —> sexual
evolutionary novelty
structure/component of an organism that allows it to perform a new function
e.g. wings, feathers, big brains
biogeography
study of the distribution of plant and animal species over time
what is the only way to create new alleles?
mutation - original source of gel. variation that serves as raw material for natural selection
characs of primates
large brains, dexterous hands, opposable thumbs, eyes in front of face, hand-eye coordination, single births, limber shoulder-joints
hominid species in order of evolution
Australopithecus and bipedalism (Lucy)
homo habilis and tools
homo erectus and large brains
homo neanderthals and large brain, hunting, tools
homo sapiens
are we still evolving?
yes
multiregional theory
human evolution started in Africa —> migrate to all 4 continents and evolve simultaneously
- less likely as all humans did not speciate
out of Africa theory
modern humans arose from ONE African like (other lines outside of Africa went extinct) and that line spread to all continents around 100,000 years ago
cladograms
models showing evolutionary relationships
Galapagos finches showed Darwin how…
one species can become isolated and diverge as they become adapted to each environment
-specifically diff beaks to eat diff food
how did antibiotic resistance increase?
went through directional selection
-same with insecticides
