test 1 Flashcards
a structure that has no apparent function in one species, yet it is homologous to a functional organ in another (human embryos tails that disintegrate before birth)
vestigial
effects of gene flow
a new individual will add new alleles to the original population, reducing genetic differences between the two groups
how many mass extinctions have we seen in the past 500 million years?
5
used to assign an age to a fossil by testing either the fossil itself or the sediments above and below the fossil, either way, the dates are usually expressed in relation to the present
absolute dating
hybrid inviability (hybrid embryo may die before reaching reproductive maturity), hybrid breakdown (some species produce hybrid offspring that are fertile when those hybrids produce their offspring may have abnormalities), hybrid infertility (some hybrids are infertile)
postzygotic barrier examples
t or f: Mendel was also studying inheritance at the same time as Darwin but neither of them knew of each other
true
hypothesis on how life developed from single-cell to multi-cell
the origin of multicellularity ushered in the possibility of specialized cells, which allowed for new features such as attachment to a surface or an upright orientation
population, or group of populations, whose members can interbreed and produce fertile offspring
how Mayr described biological species
occurs when extreme phenotypes are less fit than the optimal intermediate phenotype
stabilizing selection
describes the evolutionary tree that requires the fewest steps to construct from a set of observations
parsimonious tree
occurs when all members of a species have died, if speciation is the birth of a species extinction represents its death
extinction
how do environmental changes affect natural selection?
as the environments changes, organisms have to change with it in order to continue their bloodline, the phenotype that is “best” depends entirely on the time and place
theory that life’s history has been characterized by bursts of rapid evolution interrupting long periods of little change
punctuated equilibrium
recognize adaptation from an evolutionary perspective
individuals with the best adaptations to their existing environment are most likely to reproduce and pass their advantage to their offspring
when did life first form on earth and what were they?
prokaryotic cells 4.2-3.8 BYA
produces similar adaptations in organisms that do not share the same evolutionary lineage (desert plants)
convergent evolution
which period is known as the age of amphibians?
Carboniferous (354-290 MYA) (Paleozoic era)
the members of one sex choose their mates from among multiple individuals of the opposite sex (female birds choosing pretty male birds)
intersexual selection
two or more extreme phenotypes are fitter than the intermediate phenotype
disruptive selection
selective breeding strategy in which a human allows only organisms with desired traits to reproduce
artificial selection
number of individuals of one genotype, divided by the number of individuals in the population
genotype frequency
which era is known as the age of mammals?
Cenozoic era (65-.01 MYA) includes Paleogene, Neogene, and Quaternary
part of a population enters a new habitat bordering the range of the parent species
parapatric speciation
t or f: reproductive barriers can lead to three types of speciation, allopatric, parapatric, and sympatric
true
a large-scale evolutionary change
macroevolution
how did people respond to Darwin’s ideas?
some people embraced them, but others with religious domination had a clash with their beliefs and others may just have not liked the idea that humans were just another species competing for resources
calculated as the number of copies of that allele, divided by the total number of alleles in the population (the rate at which a specific allele appears within a population)
allele frequencies
who proposed a theory of uniformitarianism?
James Hutton
suggests that genetic mutations create heritable variation and that this variation is the raw material upon which natural selection acts
modern evolutionary synthesis
what are the levels of groups (taxa) used in the hierarchical system by Linnaeus
domain, kingdom, phylum, class, order, family, genus, species
inherited attributes that resemble those of the ancestor of a group
ancestral characters
a single species gives rise to multiple specialized forms in a relatively short time
adaptive radiation
held that evolution proceeds in small, incremental changes over many generations
gradualism
occurs when a populations size drops rapidly over a short period; randomly eliminates many alleles that were present in the larger ancestral population
bottleneck effect
When did the largest mass extinction occur?
at the end of the Paleozoic era, in the Permian
the time it takes for half of the atoms in a sample of a radioactive substance to decay (if an isotopes ____ is one year, 50% of the radioactive atoms in a sample with have decayed in a year, in another year, half of the remaining radioactive atoms will decay, leaving 25% and so on
half-life
- the biological species concept cannot apply to asexually reproducing organisms (bacteria, archaea, and many fungi and protists)
- it is impossible to apply the biological species definition to extinct organisms known only from fossils
- some types of organisms have the potential to interbreed in captivity, but they do not do so in nature
- reproductive isolation is not always absolute
problems with Linnaeus’s biological species definition (did not consider the role of evolutionary relationships)
reduce the fitness of a hybrid offspring if fertilization does occur
postzygotic reproductive barrier
what was the name of Darwin’s book and what impact did it have?
Darwin’s book was 490 pages and was called “On the Origin of Species by Means of Natural Selection, or Preservation of Favoured Races in the Struggle for Life, and it would form the underpinning of modern life science
t or f: fossils became abundant at the start of the Phanerozoic
true
the theory that suggests that a series of brief, violent, global upheavals such as enormous floods, volcanic eruptions, and earthquakes were responsible for most geological formations
catastrophism
t or f: natural populations often violate HW equilibrium
true
what are the three domains of life?
archaea, bacteria, and eukarya
- biological evolution explains the origin of life
- evolution is a random process
- in a changing environment, all individuals in a population simultaneously develop beneficial adaptations
misconceptions of natural selection
who was the first to openly suggest that closely related species arose from a common ancestor and were changing?
George-Louis Buffon
a phylogenetic system that defines groups based on characters that indicate shared ancestry
cladistics
- the vast majority of organisms never leave a fossil trace
- erosion (movement of earth’s continental plates) has destroyed many fossils that did form
- scientists are unlikely to ever discover the many fossils that must be buried deep in the Earth or submerged underwater
reasons why the fossil record is incomplete
what are the two HW equations?
p + q =1
p2 + 2pq + q2 = 1
a change in allele frequencies that occurs purely by chance, tends to eliminate alleles from a population
genetic drift
who was convinced of catastrophism and used his knowledge of anatomy to identify fossils and describe the similarities amongst organisms? As well as being the first to recognize the principle of superstition.
Georges-Cuvier
t or f: natural selection is an evolutionary mechanism
true
the study of the evolutionary relationship among species
phylogenetics
the theory that suggested that processes of erosion and sedimentation that act in modern times have also occurred in the past, producing profound changes in the earth over time
uniformitarianism
to or f: low genetic diversity in small populations can increase chance of extinction
true
T or F: populations evolve, not individuals alone
true
interbreeding members of the same species occupying the same region
population
which era is known as the age of reptiles?
The Mesozoic era (248-65 MYA) includes Triassic, Jurassic, and Cretaceous
phylogenetic (evolutionary) trees
phylogenies
temporal isolation (two species that share a habitat will not mate because they are active at different times or reach reproductive maturity at different times), behavioral isolation (behavioral differences may prevent two species from mating), mechanical isolation (any change in the shape of the gamete delivering or receiving structure may prevent interbreeding), gametic isolation (sperm cannot fertilize an egg cell), ecological isolation (difference in habitat preference separates two pops.)
prezygotic barrier examples
deep water trench that separated the islands of Borner + Java and Sulawesi
Wallace’s line
the small, generation-by-generation changes to a population’s gene pool
microevolution
t or f: adaptive radiation is common on islands
true
t or f: natural selection acts on existing mutation, and only heritable mutations affect evolution
true