Organic Evolution Flashcards

Terms Definitions
non living things
natural component of evolution
New mutationsVariable selectionIntra-species competition
New mutation
scientific study of fossils
mating is done at random
An attribute (structure, behavior, biochemical pathway, etc.) which evolved by natural selection and is useful to the organism for survival and reproductive success. e.g. bony processes in the back of egg-eating snakes throats which allow them to puncture the egg and digest the yolk e.g.2 woodpeckers stout, chisel-like beaks have a flexible cartilage between the bones and the beak which cushions the shock of each blow, AND toe arrangements two toes facing forward and two backward allowing it to cling to trees.
Which superfamily does man belong to?
Characters that show continuous variation
Polygenic Variation
Loss of function in a geneDegeneration
Two copies lose partial functions complementarily - Ex) Original gene was expressed in both brain and liver. One duplicate copy loses expression in brain. The other copy loses expression in liver.
individual is both m and f
1. Relative Dates-same fossils in different places means those places are the same age 2. Exact Date- Radio isotopes dating
46. When we compare amino acid differences to estimate the evolutionary "distance" between organisms, what assumptions are being made about the rate at which mutations occur over time?
Mutations are only important if they are heritable.
A mutation is good, bad, or indifferent. It depends on the situation. CONTEXT!
Traits that are advantageous for a given environment=>individuals with that trait are more likely to survive.
Which species does man belong to?
Homo sapiens
h2=1---> Vp=Va
phenotype differences are entirely due to genetic differences
Studying Adaptation Methods
1. Experimental (Optimality) Approach 2. Comparative Approach
Adaptive radiation
multiple species form rapidly in response to new niches (environments) opening up (availability of new resources) OR when a lineage gets a key innovation that allows it to invade a lot of niches
movement towards or away from stimulus e.g. cockroaches and light
Mechanisms of Evolutionary Change
Natural Selection, Mutation, Gene Flow, Genetic Drift
natural Selection
Due to competition, individuals in a population that have a genetic trait that gives them an advantage over other individuals without that form of a trait will produce more offspring.
a single celled individual formed by union of gametes
prezygotic isolation
codes for a DNA binding protein which regulates how DNA is turned on and off- controls where a cell goes and which genes are on and off
1. similar in detail 2. similar in position 3. similar in development 4. similar in genetic control 5. agreement with other characters
coined by Ernst Hagel, its a sequence of events in the development of an individual, otogeny recapitulates phylogeny
Von Baer;s Observations
1. general characteristics of the group to which an embryo belongs develop before unique characteristics 2. Early embryos of different kinds of animals are very similar
34. Neo-Darwinism
a. Means the same thing as "modern Darwinism."
b. Consists of Darwin's basic principles coupled with an understanding of genetics
c. Adds microevolution to macroevolution
d. Is based on new RNA molecular similarities
e. Brings together biogeography, embryology, systematics, genetics, etc
From Gould's essay "Evolution as Fact and Theory"- what is a "fact"?
The world's data
What are mutations?
chemical or physical changes in genes resulting in alteration of the sequence of bases in DNA or RNA
Genetic Crosses can be used to identify what?
Identifies polygenic variation
Xmi or Xpi
is what determines the allele or alleles this individual receives from the corresponding parent
Monophyletic Groups
Groups that can be names, consists of hypothetical ancestor and ALL its descendants, defined by an apomorphy
Cost of meiosis
The cost of breaking up a potentially well-adapted genome. Due to two haploids coming together, one from male other from female.
What occurs in migration?
individuals move into and out of populations
What occurs in vicariant speciation?
a climatic or geological event fragments a population
when multiple alleles of a gene within a population express different phenotypes
additive genetic variation
Life History Strategy
Key Events in the lifetime of an organism that determine its evolutionary success
42. Which of the following contribute(s) to evolution?
a. Mutations
b. Gene flow
c. Genetic drift
d. Natural selection
e. All of the choices are correct
Which 10 characteristics separate primates from all other animals?
1) grasping fingers and toes with opposable thumbs2) vision dominates sense of smell3) large eyes with stereoscopic and color vision4) increased ratio of brain to body size5) specialized forelimbs and clavicles6) increased sensitivity of touch receptors in hands7) increased parental investment in offspring8) complex social behavior9) 5 digits with flat nails10) body covered with hair
Va>0 <0 =0?
20. In the case described in the previous question, the salamander populations on the mountain slopes were
a. Always allopatric
b. Always sympatric
c. First allopatric, then sympatric, then allopatric
d. First sympatric, then allopatric, then sympatric
e. THERE is not enough information to determine sympatry or allopatry
What are the 4 main points of Darwin's theory of evolution?
Adaptation (overproduction of offspring)
Variation (every organism has different traits)
Natural Selection
2) Assumed that certain genetic factors, carrying continuous phenotypic values, from parents blend together to create variations in their offspring
3) did not immediately accept Mendel's theory, thinking particulate inheritance cannot explain continuous phenotypic variation
Not Perfect, Bias in Fossil Record
1. Chance of Preservation 2. Habitat (some more perservative e.g. unlikly in raniforest) 3. Hard Parts (e.g. jellyfish less likely) 4. Post-depositional processes 5. Large animals are easier to find 6. High population numbers 7. large geographic range 8. sediment type (easier to work with sand than those encased in rocks 9. distribution of paleontologists (a lot in America and Europe, hardly any in Africa)
25. Descriptions of new species of insects usually contain more diagrams of the shape of the male genitalia than head, wing or leg parts. Why?
a. This is where mutations usually express themselves in animals
b. Radiation damage to genes usually occurs in genitalia
c. Small changes in the genitalia may cause reproductive isolation while a single species can usually tolerate wider variation in head, wing, and leg morphology
d. Arthropods have hard exoskeletons so head, wing and leg structures can't vary as much
e. This is the convention or custom of entomology
What promotes rapid evolution of a species?
subdivision of the species into small populations
17. The 19th century embryologist K.E. von Baer examined recapitulation and
a. Agreed with the theory and added more experimental evidence
b. Totally disproved it with new experiments
c. Contended that early developmental stages were simply more widely shared among different animals than later, more derived developmental stages
d. Refined it to explain heterochrony and paedomorphosis
e. Proposed that it was the key to speciation
37. Which condition is NOT among the requirements of HardyWeinberg equilibrium?
a. No mutations
b. No net migration of alleles into or out of the population
c. Small population with genetic drift
d. No selection of one genotype over another
e. Sexually reproducing and randomly mating population
7. Which of the statements is true of the fossil record?
a. All of the stratified layers will be found anywhere a core sample is taken, except for human destruction
b. Provided there is no uplifting, tilt, etc., the deeper the layer, the more recently it was laid down
c. Once fossils are formed in a sedimentary layer, they are then protected from temperature and heat
d Fossil assemblages are important in identifying sedimentary layers and different layers have different assemblages of fossil
e. All of the choices are correct
puntuated equilibruium
Quantitative Traits:
Concerning phenotypes
unicellular, colonial, or multicellular saprophytic organisms
external branch
node to tip
gametes are same size
Evolution and Development: 1. Development is conserved (doesn't evolve easily) 2. Small Genetic Changes are amplified by developmental processes 3. HOw modifications to development result in evolutionary novelties (break historical constraints)
Biogenetic Law
ontogeny recapitulates phylogeny- embryological development of an individual organism follows the same path as the evolutionary history of its species (phylogeny), Mutations that occur early in development tend to be selected against, therefore early embryos look very similar
Which order does man belong to?
Phenotypes that show CONTINUOUS variation, rather than simple Mendelian discrete variation (Most phenotypic variation we observe)
Quantitative Traits:
Modern sapiens
appeared ~170 Kya in AfricaAnatomically indistinguishable from today’s humansoverlapped with Neanderthals but abruptly replaced them (in Europe about 40,000 years ago)
Paraphyletic groups
pleisiomorphy was incorrectly thought to be an apomorphy- this is a mistake which must be fixed. e.g reptiles have no single apomorphy to tie them all together.
First life old
3.9 Billion Years Old
sexual reproduction
AKA genetic recombination: offspring get half of DNA from each parent
development is accelerated or longer- juvenile of descendant resembles adult of ancestor
a HERITABLE, spontaneous change in a organism's DNA. The ultimate source of genetic variation in a population. IS RANDOM. #2 mechanism of evolutionary change
Disruptive Selection
selection operates against mean values and favors the extremes.
Ex: males and females
gene flow
individuals in populations leave one population (reduces the frequency of the traits that individual has found in the original population) and join another (increases the frequency of trait), tends to make populations more similar to each other.
What is common descent a basis for?
branch numbers
Indicate level of support or confidence
Innate behavior
simple, totally under genetic control e.g. Trophism and Taxes
development is slower or shorter than in ancestor-adult of descendant resembles juvenile of ancestor
actions or sequence of events, if under genetic control can be adaptive and evolve
the production by the sexes of gametes that contrast greatly in size, number, and energy content
drives Fecundity and Sexual selection
genetic drift
By chance, the frequency of traits will change due to random deaths of individuals not related to selective advantage or disadvantage.
early investigator of evolution
believed that characteristics from both parents blended together to make offspringDid not accept Mendel's theory, particulate inheritance cannot explain phenotypic variation
premating barriers ecological isolation- breeding at different seasons, diff. habitat
incompatibility of sperm and egg
evolutionary distance
the number of substitutions that have occurred in two sequences since their divergence from a common ancestor
field of biology that seeks to explain social behavior by considering the evolutionary advantages of the behavior e.g. explain alturism
2 types of gametic reproduction
1. isogamous 2. amisogamous
Founder Effect
a small subset of a larger parent population establishes an independent population elsewhere
Which of Darwin's 4 main points was his own original idea?
Natural Selection
How much of a species' life span does speciation make up?
Variance due to environmental variation
Va increases/decreases with increasing genetic variation (polymorphism) in the pop.?
how to calculate p distance
#of differences/#of common sites (meaning total sites)
Modes of Responses (at pop. level) to selection:
Stabilizing Selection
Directional Selection
Disruptive Selection
Changing Frequency
What even has been used as the cause for nonallopatric speciation?
sympiatric speciation
What does gradualism fail to explain?
all structural differences in species
Charles Darwin and finches
noticed a great diversity of bill morphology in closely related finches--rapid evolution upon colonization
Sampling error in biology:
When you take a sample from parent population that misrepresents the parent population. Can happen with founders effect, and with bottleneck effect.
The smaller n, the sample size, the less likely the sample reflects the full genetic variability of the parent population.
Which 7 characteristics separate hominoids from other animals?
1) no tail2) no cheek pouches3) distinctive molar teeth with a 5 point crown4) semi-erect posture5) flexible arm and shoulder joints6) ams longer than legs (except for humans)7) large, complex brain
The genetic variation caused by polygenes (follow the standard Mendelian rules of segregation)
Each polygene contributes a small amount to the value of the trait.
1. Before the 18th century, theories on the origin of species are best described as
a. Nonexistent
b. Simple, with early Greek philosophers seeing fossils as destroyed life forms, but not placing them into an evolutionary concept
c. Foundational, with early Greek philosophers seeing fossils as a continuous lineage but merely lacking the genetic understanding to explain it
d. Complete, but poorly explained in modern scientific terms until Darwin wrote more clearly
e. Fairly complete, but then repressed with the rise of creationist religions
In which two ways can allopatric speciation occur?
vicariant speciation or a founder event
Assumptions of Jukes Cantor
Each nucleotide (A, C, G, & T) occurs withequal frequency (i.e., 25% each)– All sites in a sequence have the samemutation rate– The rate of all types of substitution areidentical (e.g., A → C = A → G = A → T)– Reversibility: C → G = G → C
28. In the case of Darwin's finches, an ancestral finch species from the mainland arrived on the Galápagos Islands and later evolved into many new species via adaptive radiation. The ancestral finch species apparently did NOT undergo adaptive radiation b
a. Directional selection works better on islands
b. Competition from many other bird species on the mainland provided stabilizing selection that was absent on the islands
c. The environment on the mainland was completely uniform
d. The founder effect greatly expanded the variation in alleles in the Galápagos finch gene pool
e. The ancestral mainland finch was reproductively isolated
What is observation 3 of natural selection?
Food resources are limited, but are relatively constant most of the time. From these three observations it may be inferred that in such an environment there will be a struggle for survival among individuals.
3. As author of the book Principles of Geology, ______ presented arguments to support a theory of geological change that the earth was subject to slow but continuous erosion and uplift, following the laws of physics and chemistry similar to what is observ
a. Archbishop James Ussher
b. Jean Baptiste de Lamarck
c. Captain Robert FitzRoy
d. Charles Darwin
e. Charles Lyell
27. On the Galápagos Islands, the tool-using woodpecker finches modify twigs to pry out grubs. With no true woodpeckers on the Galápagos Islands, this behavior allows it to exploit an untapped food source. However, not all members of this species exhibi
a. Hatchlings will not know how to do this
b. It is probably not "hardwired" in the brain as a behavior passed on genetically
c. There must be a great advantage to reaching this food source for this learned behavior to be repeated by most descendants of each generation
d. As an acquired characteristic, in a strict sense this may not be part of the adaptive radiation of finches on the Galápagos
e. All of the choices are correct
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