bio test evolution Flashcards
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What are the evidences for evolution?
fossil record, biogeography, embryology, anatomy, molecular biology (dna), artificial selection
what is fossil record (related to evolution)
- the remains of past life, radioisotope reveal age, appear in chronological order in rock layers
what is biogeography(related to evolution)
study of past and present geographical distribution of species and when evolution occurred. species on islands often resemble species on closest continent
what is anatomy(related to evolution) (2 struc)
homologous structure: structures that have a similar structure but diff function (common a!)
analogous structure: do not have common evolutionary origin but preform similar functions
what is embryology(related to evolution)
study of pre-birth stages of an organism. similarities point to a common ancestor
what is molecular biology(related to evolution)
comparing DNA, similar = reflect of common ancestor
what is artificial selection(related to evolution)
involves repeatedly selecting for and purposefully breeding indv with traits useful to humans
what are vestigial structures
major functions but serve no useful function, ex: appendix, wisdom teeth
whats a transitional fossil
intermediate links between groups of organisms (tiktaalik: between mammal and fish)
what is antibiotic resistant
bacteria that evolved over time to become immune or resistant to antibiotics
what is microevolution
a gen to gen change in the frequencies of alleles within a population. evo on small scale
what is macroevolution
dramatic evo that results in new species. “speciation”
whats the hard-weinberg equilibrim
populations that do NOT change their gene pools over time are not evolving and are said to be in ahrdyweinerlquirim … condition: random sex rep
how do allele frequencies change?
mutation, gene flow, non-random mating, genetic drift, natural selection
explain mutation
a change that occurs in dna, randomly, often harmful and selected against, if occur in gametes.. can be passed on.
explain gene flow
movement of alleles from 1 population to another as a result of migration of indv.. new alleles can be introduced.
explain non-random mating
mating among indv on the basis of mate slection for a particular pheno or due to inbreeding. pref pheno: males often fight other males. inbreeding: closely related inv breed.. increases freq of homozy genotypes and harmful recessive alleles.
explain genetic drift (2 effects)
in small populations, the freuqnecies of certain alleles can be changed by chance alone
1) founder effect: change in gene pool when only a few indv start a new isolated pop. new pop limited. freq islands. lack of genetic diversity can lead to higher health conditions.
2) bottleneck effect: changes in gene distribution that result from a rapid decrease in pop size. ex: starvation.
explain natural selection
a blend of chance and sorting. increases the freq of alleles that provide reproductive advantage
what are the types of natural selection
stabalizing (MIDDLE), directional (SHIFT), disruptive (EXTREMES), sexual: appearance/behaviour ex; peacock
What is speciation?
the formation of a new species from an existing species (macroevolution)
What are the types of speciation?
Sympatric Speciation, Allopatric Speciation
What is Sympatric Speciation
Common in plants, populations within the same geographic range diverge and become reproductively isolated.
What is Allopatric Speciation
a population is split into 2 or more isolated groups by a geographic barrier. Unable to interbreed with other side because of gene pools become distinct
What is reproductive isolation?
little or no gene flow between populations
What are the two types of reproductive isolation?
Pre-zygotic barriers, post-zygotic barriers
What is pre zygotic barriers?
where mating and fertilization is prevented
what is post zygotic barriers
a zygote from mating of 2 different species; the zygote is rarely visible
how do PRE zygotic barriers happen (5) and brief explain
-Behavioural isolation (different mating songs),
-Temporal isolation (times differ),
-Habitat isolation (rarely encounter each other),
-Mechanical isolation (anatomically incompatible for mating ((elephant vs ant)))
-Gametic Isolation (zygote doesn’t form)
how do POST zygotic barriers happen (3) and brief explain
-Hybrid Inviability (normal mitosis doesn’t occur)
-Hybrid Sterility (offspring can’t reproduce)
-Hybrid Breakdown (reproductive failure that appears after the F2 generation)
How does evolution occur… name the two models
Gradualism, Punctual Equilibrium
explain Gradualism
put forth by darwin, evolutionary changes r slow, big changes occur through the accumulation of many small changes
explain Punctual Equilibrium
put forth by niles eldredge, evolution shows long periods of equilibrium that are interrupted by rapid bursts of change that result in a new species.
what are primates?
1st placental animals; evolved 65 mya (grasping hands, feet, forward-facing eyes)
What are hominoids?
group of primates with large brains, no tails, swinging arms
whats a hominid?
all modern and extinct great apes (humans, gorillas, chimps, orangutans)
What’s a hominin?
member of the human branch of the evolutionary tree, homosapiens and our extinct ancestors
primate evolution began how many years ago?
65 mya
the last common ancestor of monkeys and apes existed about how many years ago?
25 mya
the last common ancestor of humans and apes lived between how many years ago?
8 and 6 mya
the earlist humans belonged to what group?
Ardipithecus
present day humans belong to what group?
homo
when did the Ardipithecus group live, and what r some features?
7-4.4 mya, bipedalism, small canine teeth
when did the Australopithecus group live, and what r some features?
4.2-2.5 mya, longer strides, larger brains
when did the Paranthropus group live, and what r some features?
2.7-1.2 mya, large teeth, eat a variety of food
when did the Homo group live, and what r some features?
2.4 mya- present, stone tools, large brains
List the 6 major milestones in human evolution and when they first occured.
- Becoming bipedal (6mya)
- Mostly Bipedal (4mya)
- Dawn of tech - tools (2.6 mya)
- control of fire (800k yr ago)
- Rapid increase in brain size (800k-200k yr)
- Control n growth & breeding of certain plants n animals (12k yr ago)
When did the Ardipithicus Ramidus live, and give a description
4.4 mya, big toe, partial skeleton “ardi”.. shows evidence of early bipedalism
When did the Australopithecus Afarensis live, and give a description
3.8-2.9 mya, grew up rapidly, ape-like face proportions and braincase, curved fingers for climbing trees, canine teeth, two legs
When did the Australopithecus Garhi live, and give a description
2.5 mya, longer femur, long powerful arms, longer strides
When did the Homo Habilis live, and give a description
2.4-1.4 Mya, larger braincase, smaller face and teeth, ape-like features, the first maker of stone tools.
When did the Homo Erectus live, and give a description
1.9 mya-110k, elongated legs n shorter arms, human-like proportions, loss of tree climbing, walk long distances, earliest hand axes
When did the Homo Heidelbergensis live, and give a description
700k-200k yr ago, prominent brow ridge, first to live in colder climates and build shelters, hunt large animals
When did the Homo Neanderthalensis live, and give a description
400k-40k yr ago, angled cheek bones, huge nose for warming cold air, buried the dead, flowers
When did the Homo Sapiens live, and give a description
300k-present, large brains, smaller teeth, housing
what is the difference between natural selection and artificial selection
Natural selection is when organisms more adapted to their environment are more likely to survive and pass on their genes to offspring. In contrast, artificial selection involves repeatedly selecting for and purposefully breeding individuals with traits useful to HUMANS. E.g. horses, cattle
what makes something a clade?
if you only have to cut it once and if all of the single common ancestors’ descendants are included.
