Lecture Exam #1 Review Sheet Flashcards
Darwin’s belief that all organisms here today are related through descent from an ancestor that lived in the remote past
Descent with Modification
what does Darwin’s view of descent with modificiation account for?
diversity of species and also extinction events
founder of taxonomy, interpreted organismal adaptions as evidence that the creator had designed each species for a specific purpose. developed the bionomial format for naming species (Homo Sapiens)
Carolus Linnaeus
published his extensive studies of vertebrate fossils. noted that the older the stratum, the more dissimilar its fossils were to current life-forms. also observed that from one layer to the next, some new species appeared while others dissapeared.
Cuvier
did Cuvier support evolution?
no, he opposed it.
published Principles of Geology which influenced Darwin bringing him to believe that the earth was more than 6000 years old.
Lyell
published his hypothesis of evolution. he hypothesized that species evolve through use and disuse of body parts and the inheritance of acquired characteristics.
Lamarck
were Lamarck’s mechanisms he proposed supported by evidence ?
no
proposed his principle of gradualism. he proposed that the earth’s geologic features could be explained by gradual mechanisms such as valleys being formed by rivers
hutton
why was Lamarck’s ideas possibly rejected?
because our understanding of genetics show experiments showing that traits acquired by use during an individual’s life are not inherited that way.
what can evolution be defined as?
Darwin’s descent with modification
what can evolution be viewed as?
both a pattern and a process
what did Darwin hyptothesize happened to the species from South America that colonized in the Galapago Islands?
that they speciated the islands
an evolutionary process in which one species splits into two or more species.
speciation
who evolves?
individuals don’t evolve; populations evolve over time
what is Darwin’s first observation?
members of a population often vary in their inherited traits
what is Darwin’s second observation?
all species can produce more offspring that the environment can support, and many of these offspring fail to survive and reproduce
what is Darwin’s inference #1?
inviduals with traits that make them more likely to survive will tend to leave more offspring
what is Darwin’s inference #2?
the unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in population over generations
what does inference #2 explain?
the match between organisms and their environments
Darwin’s four types of data that document the pattern of evolution
1) direct observations
2) homology
3) fossil record
4) biogeography
two evidences for natural selection in direct observations
1) introduced plant species
2) the evolution of drug-resistant bacteria
the similarity resulting from common ancestry
homology
anatomical resemblnces that represent variations on a structural theme present in a common ancestor
homologous structures
type of homology that reveals anatomical homologies not visible in adult organisms
comparative embryols ogy
type of homology where remnants of features that served important functions in the oraganisms ancestors
vestigial structure
what is an example of homologies at a molecular level?
genes shared among organisms inherited from a common ancestor
hypotheses about the relationship among different groups
evolutionary trees
what do homologies form in evolutionary trees?
nested patters
what are evolutionary tree can be made with?
different types of data
what is an example of the types of data used in evolutionary trees?
anatomical and dna sequence data
provides evidence of the extinction of species, the origin of new groups and changes within groups over time
fossil record
what can fossils document?
important transitions
what is an example of an important transition that fossils documented?
the transition from land tot sea in the ancestors of cetaceans
the scientific study of the geographic distribution of species, provides evidence of evolution
biogeography
what is an example of biogeography?
Earth was formerly Pangaea before it separated by continental drift
the evolution of similar or analogous features in distantly related groups
convergent evolution
how to analogous traits arise?
when groups independetly adapt to similar environments in different ways
what does convergent evolution not provide info about ?
ancestry
advantages of Mendel using pea plants (4) (MMEC)
1) many varieties with distinct features or characters (flower color)
2) Mating can be controlled
3) each has sperm-producing organs (stamens) and egg-producing organs (carpels)
4) cross-pollination
an obersevable heritable feature that may vary among individuals
character
one or two or more detectable variants in a genetic character
trait
any of the alternative versions of a gene that may produce distinguishable phenotype effects
allele
referring to organisms that produce offspring of the same variety over many generations of self-pollination
true breeding
the mating, or crossing of two true-breeding varieties
hybridization
a cross between two organisms that are heterozygous for the character being followed (or the self-pollination of a heterozygous plant)
monohybrid cross
the true breeding (homozygous) parent individuals from which F1 hybrid offspring are derived in studies of inheritance
P Generation
the first filial, hybrid (heterozygous) offpsring from a parental (p generation) cross
F1 generation
the offspring resulting from interbreeding (or self-pollination) the hybrid F1 generation
F2 generation
an allele that is fully expressed in the phenotype of a heterozygote
dominant
an allele whose phenotype effect is not observed in a heterozygote
recessive
having two different alleles for a given gene
heterozygous
having two identical alleles for a given gene
homozygous
the genetic makeup, or set of alleles of an organism
genotype
the observable physical and physiologial traits of an organism, which are determined by its genetic make up
phenotype
how does sexual recombination generate genetic variability?
it shuffles existing alleles into combinations
are sexual reproductions more important than mutations?
yes
a localized group of individuals capable of interbreeding and producing fertile offspring
population
in real populations what changes over time?
allele and genotype frequencies
a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring but not produced viable, fertile offsrping with members of such groups
species
consists of all the alleles for all loci in a population
gene pool
the contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals
relative fitness
in relative fitness what does selection favor?
certain genotypes by acting on the phenotypes of individuals
the usual result of point mutations in non coding regions,conferring no selective avantage or disadvantage
neutral variation
why can mutations be neutral?
redundancy in the genetic code
5 conditions for the hardy weinberg equilibrium
1) no mutations
2) random mating
3) no natural selection
4) extremely large population size
5) no gene flow
how does population size affect genetic drift?
the smaller a sample, the greater the chance of random deviation from a predicted result
three modes of selection
1) directional
2) disruptive
3) stabalizing
mode of selection that favors individuals at one extreme end of the phenotypic range
Directional selection
what is an example of directional selection?
lighter mice being selected against because they live among dark rocks, which would make it harder for them to hide from predators
mode of selection that favors individuals at both extremes of the phenotypic range
disruptive selection
what is an example of disruptive selection?
habitat is made up of light and dark rocks therefore, the mice of an intermediate color (brown) are selected against (black and white mice)
favors intermediate variants and acts against extreme phenotypes
stabalizing selection
what is an example of stabalizing selection?
if rocks are an intermediate color, both light and dark mice will be selected against
direct competition among individuals of one sex (often male) for mates of the opposite sex
intrasexual selection
occurs when individuals of one sex (usually female) are choosy in selecting their mates
intersexual selection
what is intersexual selection often called?
mate choice
what can male showiness due to mate choice increase?
a male’s chances of attracting a female, while decreasing his chances of survival
4 reasons why natural selection can’t produce perfect organisms (4) (SEAC)
1) selection can only act on existing variations (Michael phelps example)
2) evolutions is limited by historical constraints
3) adaptions are often compromises
4) chance, natural selection and the environment interact
what are the mechanisms of evolution?
1) the founder effect
2) the bottleneck effect
3) gene flow
4) genetic drift
occurs when a few individuals become isolated from a larger population
the founder effect
in the founder effect what can allele frequencies in the smaller founder population be different from?
the larger parent population
a sudden reduction in population size due to a change in the environment
the bottleneck effect
in the bottleneck effect what may no longer be reflective of the original population’s gene pool?
the resulting gene pool
in the bottleneck effect, if the population remains small what may be it be further effected by?
genetic drift
what can understanding the bottleneck effect increase our understanding about?
how human activity affects other species
what type of populations is genetic drift significant?
small
what can genetic drift cause?
allele frequencies to changes at random
what can genetic drift lead to a loss of?
genetic variation within populations
what can genetic drift cause harmful alleles to become?
fixed
consists of the movement of alleles among populations
gene flow
in gene flow how can alleles be transferred?
through the movement of fertile individuals or gametes (pollen)
what does gene flow tend to reduce?
variation among populations over time
what can gene flow increase?
fitness of population
