evolution unit Flashcards
what is evolution
biological history of life and how it became what it is today
what is LUCA
last universal common ancestor
who first gave a mechanism as to how evolution works
Charles Darwin
what are the 5 main pieces of evidence that support evolution?
fossil record, biogeography, embryology, anatomy, DNA (FBEAD)
what kind of fossil is Tiktaalik?
a transitional fossil that shows the transition from aquatic life to four legged land vertebrates
in what kind of rock are fossils found and which layer
in the strata of sedimentary rock
chronological evolution goes..
bacteria & algae, fungi & worms, land vertebrates
what is the oldest vertebrate
fish
biogeography is evidence for
how and why evolution occurs
geographically close environments are likely to be populated by
related species
what is embryology
the study of early pre birth stages of an organism’s development
what is a homologous structure
structures that have SIMILAR STRUCTURE but may have DIFFERENT FUNCTION
what is adaptive radiation
when forelimbs of vertebrates have similar structures but may have different uses
what is a pentadactyl limb
what id the oldest vertebrate
fish; then amphibians, reptiles, birds, and mammals
what is biogeography evidence of
how and why evolution occurs
what is embryology
study of early pre birth stages of an organism’s development
what is a homologous structure
structures that have SIMILAR STRUCTURE but often have DIFFERENT FUNCTION
what is adaptive radiation
when forelimbs of vertebrates have similar structures but different uses
what is a pentadactyl limb
homologous structure; limbs with five digits, characteristic of 4 legged vertebrates (eg. human arm, whale fin)
what are analogous structures
structures that do not have common evolutionary origin, but have similar functions-CONVERGENT EVOLUTION
what are vestigial structures
remains of functional structure present in an ancestral species- present in REDUCED form (eg. wisdom teeth, appendix)
what is artificial selection
repeatedly selection for purposefully breeding individuals with traits useful to humans (cattle, horse, dogs)
what applied selective pressure in artificial selection?
humans
what is natural selection
theory developed by Darwin that describes the process by which individuals with inherited characteristics that are well suited to their environment leave more offspring expressing those genes
what is differential reproductive success
a situation in which some individuals leave more offspring in the next generation than do others, often due to traits that confer advantages in survival and/or reproduction
what is fitness
individual’s ability to survive and reproduce in its environment
what are some examples of natural selection
antibiotic resistance, industrial melanism, the finches in Daphne Major
how does antibiotic resistance happen
- lots of germs, some are drug resistant. 2. antibiotics kill bacteria causing illness, as well as good bacteria protecting the body. 3. the drug resistant bacteria remain. 4. some bacteria give their resistance to other bacteria.
can drug resistance be passed on to other bacteria even when the bacteria is killed?
yes
what is micro evolution
evolution on the smallest scale; generation to generation change in the frequencies of alleles within a population
what is the term for when populations do not change their gene pools over time and are not evolving
Hardy-Weinberg Equilibrium
what is macroevolution
also called SPECIATION; more dramatic evolutionary changes that result in a new species
how do allele frequencies change? (5 factors)
mutation, gene flow, non-random mating, genetic drift, natural selection (MGNGN)
mutations are often..
harmful and would be selected against
what is gene flow
movement of alleles from one population to another as a result of migration of individuals
what is genetic drift
when frequencies of certain alleles in populations are changed by chance
what is the founder effect
change in gene pool when only a few individuals (founders) start a new, isolated population, often occurring on islands
what is the bottleneck effect
changes in gene distribution that result from a rapid decrease in population size
what are the three types of natural selection
stabilizing selection, directional selection, and disruptive selection
what is stabilizing selection
favours intermediate pheno., acts against extreme variants (eg. human birth weights)
what is directional selection
favouring extreme variants of a trait- shift away from average (common in artificial selection)
what is disruptive selection
favours individuals with variations at either extreme of a trait over individuals with the intermediate variations- two different phenotypes
what is speciation
formation of a new species from an existing species (macro evolution)
what is a species
population or group of populations whose members can interbreed to produce viable, fertile offspring
what are the types of speciation
sympatric and allopatric
what is sympatric speciation
more common in plants- populations within same geographic range diverge and become reproductively isolated
what is polyploidy
error in cell division that results in multiple sets of chromosomes
what is allopathic speciation
population split into 2 or more isolated groups by a geographic barrier- also known as geographic speciation
how does speciation occur
reproductive isolation- little to no gene flow between populations
explain pre zygotes barriers in reference of reproductive isolation
mating & fertilization are prevented; occurs because of behavioural, temporal (breeding times), habitat, mechanical (anatomically incompatible), and gametic isolation
explain post zygotic barriers in reference of reproductive isolation
rarely will a zygote even form from mating of 2 different species, let alone be visible. it’s caused by hybrid inviability, hybrid sterility, and hybrid breakdown.
what is divergent evolution
evolution from a common ancestor that results in diverse species (adaptive radiation)
what is convergent evolution
distantly related species that live in similar environments developing similar adaptations
what is gradualism
slow and steady evolutionary change
