Biology Evolution Ch.13
why is embryology importance evidence of evolution
it allows us to see embryological similarities and differences between the early stages of related organisms (ex: all chordates have a gill slit during development)
what is comparative anatomy/ why is it important evidence of evolution
it compares different body parts of different animals
what is Batesian mimicry
non-harmful animal resembles a harmful animal
what is sexual selection
non-random mating between males and females, traits selected may be favorable for reproduction but not for survival
what are the two theories of macroevolution
phyletic gradualism and punctuated equilibrium
what is cladogenesis
the splitting apart of evolutionary lineages; the formation of new clades
Darwin's finches and adaptive radiation
the studied finches originated from the same ancestor from the mainland, as the finches flew to each small island, they grew apart from their ancestors and became different species that "radiated" away from the main branch of original finches.
what is paleontology
the study of fossils through actual remains of an animal or their traces
why is biochemical comparison of DNA important evidence for evolution
it allows for DNA sequence comparisons to see conserved DNA sequences and common conserved pathways
what is convergent evolution
unrelated species adapt to similar environments, becoming more alike (analogous structures)
what was Lamark's theory of evolution based on
use and disuse & the inheritance of acquired traits
what did Lamark say about use and disuse
used body parts will develop and unused ones are weakened, leading to evolution
examples of vestigial structures
-Wings of ostrich, homologous to wings of eagles. -Appendix of humans, homologous to cecum of cows
what are the four requirements for natural selection
1. demand for resources exceeds supply, which results in competition for survival (fittest survive to pass on genes) 2. difference in levels of fitness due to variation in traits, differentiating the ability to compete and survive 3. variation in traits must be genetically-influenced to be passed onto offspring 4. variations in traits must be significant for reproduction and/or survival, genes improving reproductive success/survival are favored and increase over generations and vice versa
evolution of chordates
1. notochord (first seen in lancelets and tunicates) 2. head (first seen in hagfish) 3. vertebral column (first seen in jawless fish (also known as Class Agnatha, e.g. lampreys) 4. jaw and mineralized skeleton (first seen in chondrichthyes, e.g. sharks) 5. lungs/lung derivatives (first seen in ray-finned fish) 6. lobed fins 7. limbs with digits (amphibians) 8. amniotic eggs (reptiles) 9. production of milk (mammals).
All of the following would disrupt genetic equilibrium EXCEPT one. Which is the EXCEPTION? A. Polyploidy B. Isolated population C. Genetic drift D. Inbreeding E. Natural selection
B. isolated population Genetic (Hardy-Weinberg) equilibrium is a condition where there are no changes in allele frequencies (evolution). For genetic equilibrium, the population will need to be Large, mate Randomly, and experience no Mutations, natural selection, or Migration. Remember these conditions using Large, Random M&M (read & like "n"). This question asks us to find the choice that would not disrupt genetic equilibrium. Isolated populations do not migrate. Therefore, choice [B] does not disrupt genetic equilibrium, and is our answer.
2 types of mimicry
Batesian and Mullerian
example of sympatric speciation
Centuries ago, some members of a maggot fly population began laying their eggs on apples instead of hawthorns. Now there are two types of flies that can no longer produce viable offspring: one that lays eggs on hawthorns and the other on apples... A scenario in which two groups within the same species are gradually becoming different species and the speciation is occurs without the presence of a geographical barrier
who proposed the three theories of evolution
Cuvier, Lamarck, and Darwin
honorable mention evolution theorists and their theories
Gause - competitive exclusion principle = two species are not able to occupy the same niche while also maintaining their population levels. In the long run, the species that is more adapted to the niche will outcompete and dominate the other species. Malthus - principle of population = the human population increases geometrically (ie., 2, 4, 16, 132...), while food production increases arithmetically (ie., 2, 4, 6, 8...). This means that food production will not be able to keep up with growth in the human population, resulting in disease, famine, war, and calamity.
two types of genetic drift
bottleneck effect and founder effect
example of Batesian mimicry
Two different species of butterflies look nearly identical, but only one species is poisonous when eaten.
what is a phylogenetic tree
a branched diagram that shows inferred evolutionary relationships between different taxa
what is an internal node of a phylogenetic tree
a branching point on a cladogram that represents the splitting/divergence of a single group into two descendant groups
what is the Hardy-Weinburg formula
a calculation of frequency during genetic equilibrium, with no change in gene frequencies, and if both equations hold true then the population is under the Hardy-Weinberg equillibrium
what are mutations for causing microevolution
a change in DNA that can be dormant until environmental change allows it to flourish
what is a clade
a cluster with an ancestor and all its decendents
what is a cladogram
a type of phylogenetic tree that shows inferred evolutionary relationships among various biological species
what is a specific type of allopatric speciation
adaptive radiation
what is genetic drift for causing microevolution
allele frequencies change by change, creating larger effects on smaller populations
what are 2 types of speciation
allopatric and sympatric speciation
what is a monophyletic tree
an ancestor and all its descendants
what is a paraphyletic tree
an ancestor and some but not all of its descendants
what is polytomy
an internal node of a phylogenetic tree that leads to more than two tips
what are 3 types of sympatric speciation
balanced polymorphism, polyploidy, and hybridization
what is postzygotic isolation
barriers to organism success after the zygote has formed
why is Lamark's ideas on inheritance of acquired traits INCORRECT
because acquired traits are generally not heritable
what does evolution increase
biodiversity
what is an example of stabilizing selection
birth weight
what is an example of difference in levels of fitness due to trait variation
black peppered moths favored over white moths to live during the Industrial Revolution (lots of soot/ash in the environment gave better camouflage for the peppered moths)
what is crypsis
camouflage + the inclusion of olfactory/smell or auditory methods of concealment (scent masking, silencing)
what are 4 types of coevolution
camouflage, crypsis, aposematic coloration, mimicry
what did Cuvier say about catastrophism
catastrophes lead to mass extinction of species in the area; different populations in different areas were shaped by catastrophes that occurred because random organisms that survived would repopulate the area
what was Cuvier's theory of evolution based on
catastrophism
for genetic variation, sexual reproduction is
crossing over, independent assortment and random joining of gametes
what is camouflage
cryptic coloration; matching appearance to the environment to avoid detection, and it's strictly a visual method of concealment
what is behavioral isolation
different courtship rituals
what is balanced polymorphism for sympatric speciation
different phenotypes are isolated within the same area
what are the 4 main patterns of evolution
divergent, convergent, parallel, coevolution
What is phyletic gradualism?
evolution happened gradually via accumulation of small intermediary changes
when the Hardy-Weinberg conditions are met, what happens
evolution occurs
what is mimicry
evolution to resemble another species
for genetic variation, mutation must not be...
fatal
what are the female and male preferences in sexual selection
females favor high quality partners and males prefer a high quantity of partners to increase their number of offspring
what are ichnofossils
fossilized traces of organisms but not the organisms themselves
what are the 5 types of evidence of evolution
fossils, biogeographic spread of species, embryology, comparative anatomy, and biochemical comparison of DNA
what is gamete isolation
gametes do not recognize/fertilize each other (ex: zona pellucida on mammalian oocytes)
what factors can cause microevolution
genetic drift, non-random mating, mutations, natural selection, and gene flow
5 types of prezygotic isolation
habitat, temporal, behavioral, mechanical, and gamete
macroevolutional species are reproductively isolated. what is that?
isolation via prezygotic and postzygotic isolating mechanisms that result in a lack of gene flow between species
what are allele frequencies
heritable traits
what are genetically-influenced traits
heritable traits
3 types of advantages from balanced polymorphism
heterozygote, hybrid, and minority advantages
Example of Hardy-Weinberg Equilibrium equation: In a population of rabbits, brown fur color is dominant and white fur color is recessive. 91% of the population is brown and 9% is white. What is the heterozygous frequency?
heterozygous frequency = 2pq in p^2 + 2pq + q^2 = 1 white fur = recessive = bb = 9% = 0.09 homozygous recessive (bb) frequency = q^2 = 0.09 q = 0.3 p + q = 1 p + 0.3 = 1 p = 0.7 2pq = 2(0.7)(0.3) = 2(0.21) = 0.42 x 100 = 42%
what is conserved DNA
high similarity DNA, which means theres higher relatedness in the organisms
what is convergent evolution also known as
homoplasy
Example of Hardy-Weinberg Equilibrium equation: Assume a population is in Hardy-Weinberg equilibrium. If 25% of the population is homozygous recessive, what is the allele frequency of the dominant allele?
homozygous recessive = q^2 in p^2 + 2pq + q^2 = 1 q^2 = .25 -> q = 0.5 p + q = 1 p = 1 - 0.5 = 0.5 x 100 = 50% (p= dominate allele, both for the homozygous and heterozygous presence)
what is speciation
how species form, starting with reproductive isolation, which leads to interruption of gene flow between populations that gradually develop into two species
what are the 3 types of postzygotic isolation
hybrid mortality, hybrid sterility, hybrid F2 breakdown
what is survival of the fittest
individuals with the greatest fitness have the greatest success and pass on more DNA to future generations, compared to less fit parents
is punctuated equilibrium accurate
it is likely to be true because it is supported by fossil evidence
why is biogeographic evidence important for evolution
it shows the spread of different species around the world which can be analyzed through their similarities and differences
the evolution of fish, from earliest to latest ancestor?
jawless fish -> cartilaginous fish -> lobe-finned fish
requirements for the Hardy-Weinberg equilibrium
large population to minimize genetic drift, random mating, no mutation, no natural selection, no migration (gene flow) so the population must be isolated
what is macroevolution
long-term evolution that occurs at a level at or higher than species
what is stabilizing selection
mainstream (average) is favored
for genetic variation, balanced polymorphism...
maintains a variety of phenotypes within a population
what is mechanical isolation
male/female genitalia are not compatible.
What is prezygotic isolation
mechanisms are barriers that prevent fertilization and zygote formation from occurring between species
what is gene flow for causing microevolution
migration (non-random) moving alleles between populations, leading to variation through mixing
preferred phylogenetic tree
minimal evolutionary reversals, convergent evolution, and parallel evolution
phylogenetic trees can be...
monophyletic or paraphyletic
what is polytomy also known as
multifurcation
for genetic variation, polyploidy is
multiple copies of alleles introducing more variety and preserving different alleles. they can also mask effects of harmful recessive alleles.
what are the sources of genetic variation
mutation, sexual reproduction, balanced polymorphism, polyploidy
what was Darwin's theory of evolution about
natural selection
what is natural selection for causing microevolution
no luck is involved
is phyletic gradualism accurate
not likely to be true because it is not supported by fossil evidence
what is habitat isolation
occupying different habitats
what is directional selection
one extreme favored
Hardy-Weinburg equations
p + q = 1 p^2 + 2pq + q^2 = 1
p + q = 1 variables
p = frequency of dominant allele q = frequency of recessive allele
p^2 + 2pq + q^2 = 1 variables
p = frequency of homozygous dominant pq = frequency of heterozygous q = frequency of homozygous recessive
Two organisms from different species mate, and the offspring of their offspring have reduced fitness. This is an example of...
postzygotic isolation, specifically hybrid f2 breakdown if the original organisms are the F1 hybrids that can reproduce and create the F2 offspring with reduced fitness
what are the 2 types of macroevolution
prezygotic isolation and postzygotic evolution
what are vestigial structures in comparative anatomy
structures that serve no purpose but are homologous to functional structures in other organisms
genetic diversity happens during meiosis stages...
prophase I (chromosome cross-over) and metaphase/anaphase I (chromosomes assort randomly and are pulled to the poles to create the chromosome makeup for the 2 future daughter cells)
what is minority advantage
rare phenotypes that offer higher fitness, cycling between high and low frequency
what is disruptive selection
rare traits are favored, mainstream is not
what is embryology
study of embryos and their development
what is temporal isolation
reproducing at different times/seasons
what is polyploidy for sympatric speciation
results from nondisjunction during meiosis (two 3n organisms, usually sterile, meet and are reproductively compatible)
what is artificial selection
selection carried out by humans to selectively breed for specific traits (ex: dog breeding)
besides natural, what are two other types of selection
sexual and artificial
what is non-random mating for causing microevolution
sexual selection, outbreeding, inbreeding
what is punctuated equillibrium
short spurts of evolutionary changes during periods of stasis
what is an example of heterozygote advantage
sickle cell anemia
what is parsimony
simpler explanations of evolution are more likely to be correct
what is an example of disruptive selection
snails living in low and high vegetation areas
what is hybridization for sympatric speciation
some hybrids are more fit than purebreds
what is allopatric speciation
speciation that occurs due to a geographical barrier
what is adaptive radiation
speciation that occurs when many species arise from one ancestor as they adapt differently from their environments. species can specialize to fill different niches within the same environment. may or may not have a geographical barrier involved (ex: Darwin's finches on Galapagos Island)
what is sympatric speciation
speciation that occurs without geographic isolation
what is parallel evolution
species diverge from a common ancestor but undergo similar changes
what are the three types of natural selection
stabilizing, directional , and disruptive selection
what are analogous structures in comparative anatomy
structures that have the same function but not have a common ancestor (ex: bird wings and bat wings)
what are homologous structures in comparative anatomy
structures that may or may not perform the same function but have a common ancestor (ex: forearm of the bird and forearm of the human)
differences between sympatric, adaptive, and allopatric speciation
sympatric = WITHOUT geographical barriers adaptive = with OR without geographical barriers allopatric = WITH geographical barriers
what is an example of a common conserved pathway
the Krebs cycle
what is fitness
the ability to survive and produce viable and fertile offspring
what does natural selection lead to
the evolution of the POPULATION, not individuals
what is microevolution
the process when gene frequencies change within a population over generations (favorable genes increase, unfavorable decrease)
what is evolution
the gradual development and change of heritable traits in populations over successive generations
what is anagenesis
the gradual evolution of interbreeding population without splitting
what is natural selection
the gradual, non-random process where allele frequencies change as a result of environmental interaction
what is the individual with the most fitness in a population
the individual with the greatest amount of offspring
what is an example of directional selection
the longest giraffe neck allows access to the most leaves
what did Lamark say about inheritance of acquired traits
traits acquired through use and disuse are passed onto offspring (ex: giraffe's stretching neck will cause its neck to develop and produce long-necked offspring)
what is Mullerian mimicry
two poisonous animals resemble each other to warn their predator
what is coevolution
two species impart selective pressure on each other
what is hybrid advantage
two strains of organisms produce more superior offspring
what is aposematic coloration
warning coloration; vibrant coloration in poisonous animals to warn predators
why is paleontology importance evidence of evolution
we can observe the development of species through time by comparing deepest fossils to shallowest
what is the founder effect
when some individuals migrate away from a population and the genetic frequencies change because of the new lack of diversity
what is divergent evolution
when species diverge from a common ancestor
when do neutral variations become a beneficial kind of balanced polymophism
when the environment changes
what is hybrid sterility
when the hybrid zygote is infertile
what is hybrid mortality/inviability
when the hybrid zygote is non-viable and does not survive past the embryonic stage, often due to different chromosome numbers
what is hybrid f2 breakfown
when the offspring of hybrids have decreased fitness
what is the bottleneck effect
with a smaller gene pool, some alleles may be lost by chance (ex: natural disaster killing a majority of the population)