96 terms

AP Bio: Evolution Vocab


Terms in this set (...)

Examples of evidence of evolution
Direct observation, homology, fossil record, biogeography
Similarity resulting from common ancestor (tree-thinking) homologous/analogous structures
Fossil record
Documents the pattern of evolution
geographic distribution of species (pangea)
Analogous structures
Share similar function, but not common ancestry
Homologous structures
Share common ancestry, but not necessarily similar function (ex. dogs human and whales have the same bone structure from shoulder to finger)
How mutations can produce genetic variation
Genetic variation in which evolution depends originates when mutation, gene duplication, or other processes produce new alleles and new genes
How sexual reproduction can produce genetic variation
existing genes are arranged in new ways (crossing over, independent assortment of chromosomes, and fertilization)
5 conditions of Hardy Weinberg
1. Population must be large
2. Population must be isolated from other populations
3. No mutations in population
4. Mating must be random
5. No natural selection
Two equations of Hardy Weinberg
p + q = 1

p^2 + 2pq + q^2 = 1
HW: p=
Frequency of dominant allele in population
HW: q=
Frequency of the recessive allele in a population
HW: p^2 =
Percentage of homozygous dominant individuals
HW: q^2 =
Percentage of homozygous recessive individuals
HW: 2pq =
Heterozygous individuals
Biological concept of species
According to this concept, a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring--but do not produce viable, fertile offspring with members of such groups
Prezygotic barriers
"Before the zygote" prevents reproduction by making fertilization unlikely. Prevents genotypes from entering a populations gene pool through geographic, ecological, behavioral, or other differences
Postzygotic isolation
Occurs when fertilization has occurred but a hybrid offspring cannot develop or reproduce. Prevents offspring survival or reproduction.
Geographic isolation
Isolation occurs when species are separated (ex.Mountains, etc)
Two types of polyploidy
Autopolyploid & allopolyploid
Punctuated equilibrium
Describes periods of apparent status punctuated by sudden change
When species do not show a punctuated pattern and instead they change more gradually over long periods of time
A specific hypothesis about the origin of life on earth
1. The abiotic (nonliving) synthesis of small organic molecules such as amino acids and nitrogenous bases
2. The joining of these small molecules into macromolecules such as proteins and nucleic acids
3. The packaging of these molecules into protocells, droplets with membranes that maintained an internal chemistry different from that of their surroundings
4. The origin of self replicating molecules that eventually made inheritance possible
The age of the earth when prokaryotic and eukaryotic life emerged
Early prokaryotes were earths sole inhabitants from at least 3.5 billion years ago to about 2.1 billion years ago. the oldest widely excepted fossils of eukaryotic organisms are about 2.1 billion years old
How Miller and Urey tested the Oparin-Haldane hypothesis
1. the water mixture in the "sea" flask was heated; vapor entered the "atmosphere" flask
2. The "atmosphere" contained a mixture of hydrogen gas, methane, ammonia, and water vapor
3. Sparks were discharged to mimic lightning
4. A condenser cooled the atmosphere, raining water and any dissolved molecules down the sea flask
5. As material cycled through the apparatus, Miller periodically collected samples for analysis
What Miller/Urey learned from Oparin-Haldane experiment
Miller identified a variety of organic molecules that are common in organisms. These included simple compounds, such as formaldehyde and hydrogen cyanide, and more complex molecules, such as amino acids and long chains of carbon and hydrogen known as hydrocarbons
How continental drift can explain the current distribution of species (biogeography)
Continental drift is the slow movement of earths continents overtime. We can use our understanding of evolution and continental drift to predict where fossils of different groups of organisms might be found
Evidence for endosymbiosis
The inner membranes of both mitochondria and plastids have enzymes and transport systems that are homologous to those found in the plasma membrane of living prokaryotes. Also, mitochondria and plastids replicate by a splitting process that is similar to that of certain prokaryotes. Also, mitochondria and plastids contain a single, circular DNA molecule that, like the chromosomes in bacteria, is not associated with histones or large amounts of other proteins.
Dissent with modification; a change in the genetic composition of the population from generation to generation
Natural selection
A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. Survival of the fittest.
The study of fossils
Vestigial structures
Remnants of features that served a function in the organisms ancestors. ex: some skeletons of snakes retain vestiges of the pelvis and leg bones of walking ancestors
Natural selection can alter the frequency distribution of heritable traits in three ways:
Directional, disruptive, and stabilizing selection
Directional selection
Occurs when conditions favor individuals exhibiting one extreme of the phenotypic range, thereby shifting a populations frequency curve for the phenotypic character in one direction or the other
Disruptive selection
Occurs when conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes
Stabilizing selection
Acts against both extreme phenotypes and favors intermediate variance
Sexual selection
A formal selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates
The process by which one species splits into two or more species
Reproductive isolation
The existence of biological factors (barriers) that impede members of two species from interbreeding and producing viable, fertile offspring. (Prezygotic & postzygotic barriers)
Habitat isolation
Two species that occupy different habitats within the same area may counter each other rarely, if at all, even though they are not isolated by obvious physical barriers, such as mountain ranges
Behavioral isolation
Courtship rituals that attract mates and other behaviors unique to a species are effective reproductive barriers, even between closely related species. Such behavior rituals enable mate recognition- a way to identify potential mates of the same species
Temporal isolation
Species that breed during different times of the day, different season, or different years cannot mix their gametes
A species may originate from an accident(mutation) during cell division that results in extra sets of chromosomes. (4n & 8n) Occasionally occurs in animals but is far more common in plans. Two types: autopolyploidy and allopolyploid
Allopatric speciation
Gene flow is interrupted when a population is divided into geographically isolated subpopulations
Sympatric speciation
occurs in populations that live in the same area and can occur if gene flow is reduced by polyploidy, habitat differentiation, and sexual selection
How allopatric and sympatric speciation are similar and different
similar: they both can cause speciation depending on how gene flow is interrupted between populations of the existing species
Different: Allopatric is isolated geographically and sympatric has no barrier (occurs in populations that live in the same geographic are)
Genetic drift
Chance events that can also cause allele frequencies to fluctuate unpredictably from one generation to the next, especially in small populations.
Two types of genetic drift
Bottleneck effect and founder effect
Bottleneck effect
A sudden change in the environment, such as a fire or flood, may drastically reduce the size of a population. A severe drop in population size causes bottleneck effect
Founder effect
When a few individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool differs from the source population
Gene flow
The transfer of alleles into or out of the population due to the movement of fertile individuals or their gametes
A change in the nucleotide sequence of an organisms DNA
Inheritance of acquired characteristics
Lamarck stated that an organism can pass modifications to its offspring, (long, muscular neck of living giraffe had evolved over many generations as giraffes stretch their necks even higher.)
Use and disuse
Lamarck's idea that parts of the body that are used extensively become larger and stronger, while those that are not used deteriorate. Ex: a giraffe stretches it's neck to reach leaves on high branches
Antibiotic resistance
bacteria can exchange genes with members of their own and other species to avoid being killed by certain antibiotics. Ex: MRSA
Genetic variation
Differences among individuals in the composition of their genes or other DNA sequences
Sexual reproduction
Two parents give rise to offspring that have unique combinations of genes inherited from the two parents
In diploid eukaryotes, a considerable amount of genetic variation is hidden from selection in the form of recessive alleles
Heterozygous advantage
Individuals who are heterozygous at a particular locus have greater fitness then both kinds of homozygous. example: sickle cell anemia
Frequency dependent selection
The fitness of the phenotype depends on how common it is in the population
Evolutionary neutral traits (neutral variation)
Differences in DNA sequences that do not confirm a selective advantage or disadvantage
Charles Darwin
Wrote the origin of species; his explanation of the process of evolution is that natural selection is the primary cause of the observed pattern of evolutionary change
Georges Cuvier
Developed paleontology; opposed idea of evolution and advocated catastrophism- the principle that events in the past occur suddenly and were caused by mechanisms different from those operating in the present
Gregor Mendel
Wrote a groundbreaking paper on inheritance in pea plants, just a few years after Darwin published origin of species
Niles Eldredge & Stephen Jay Gould
Coined the term 'punctuated equilibrium' to describe the periods of apparent status punctuated by seven change
Characteristics of the early planet and its atmosphere
No free oxygen, the early Earth had intense heat, lightning and UV radiation that provided energy for the many chemical reactions that occurred to ultimately produce the first cell.
The age of the earth and when prokaryotic and eukaryotic life emerged
Age of the earth: 4.6 billion
Prokaryotes: 3.5 billion years ago
Eukaryotes: 1.5 billion years ago
Closely related organisms go through similar stages in their embryonic development because they evolved from a common ancestor
How extinction events open habitats that may result in adaptive radiation
Periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles, or niches, in their communities. Large-scale adaptive radiation's occurred after each of the five big mass extinctions, when survivors became adapted to the many vacant ecological niches.
Methods used to date fossils and rocks
One of the most common techniques is radiometric dating, which is based on the decay of radioactive isotopes. In this process, a radioactive "parent" isotope decays to a "daughter" isotope at a fixed rate. The rate of decay is expressed by the half-life, the time required for 50% of the parent isotope to decay.
How fossil evidence contributes to our understanding of change in life on earth
The fossil record shows that there have been great changes in the kinds of organisms on earth at different points in time. Many past organisms were unlike today's organisms, and many organisms that once were, common and are now extinct.
an individual that has more than two chromosome sets that are all derived from a single species. In plants, for example, the failure of cell division could double a cells chromosome number from a diploid number to a tetraploid number.
Occurs when two different species interbreed and produce hybrid offspring. Most such hybrids are sterile because the set of chromosomes from one species cannot pair in meiosis with the set of chromosomes from another species. However, an infertile hybrid may be able to propagate itself asexually
How autopolyploidy or an allopolyploid chromosomal change can lead to sympatric speciation
A species may originate from accident during cell division that results and extra sets of chromosomes
Patterns of evolution
Divergent evolution, convergent evolution, coevolution, parallel evolution, adaptive radiation
Divergent evolution
Occurs when a population becomes isolated for any reason from the rest of the species and becomes exposed to new selective pressures, causing it to evolve into a new species(homologous structures)
Convergent evolution
When unrelated species occupy the same environment, they are subject to some more selective pressure and show similar adaptations (analygous structures)
Parallel evolution
Describes two related species that have made similar evolutionary adaptations after their divergence from a common ancestor
Is the mutual evolutionary set of adaptations of two interacting species
Adaptive radiation
Emergence of several species from a single common ancestor distributed into an environment (darwins finches)
Artificial selection
The selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits
Comparative anatomy
Organisms that have similar anatomical structures are related to each other and share a common ancestor
Anaerobic heterotrophic prokaryotes
Heterotroph hypothesis: the first cells on earth were anaerobic heterotrophs and prokaryotes. They absorbed the material from the surrounding ocean (primordial soup) as the nutrient source. Rain probably came and washed the organic molecules into the ocean to form what is called primordial soup
Nonrandom mating
New traits do not pass quickly to the rest of the population
Random mutation
New variations appear in the population with each new generation
Flora & fauna
Flora: flowers
Fauna: animals
In diploid eukaryotes, a considerable amount of genetic variation is hidden from selection in the form of recessive alleles. Recessive alleles that are less favorable than the dominant counterparts, or even harmful in the current environment, can persist by propagation in heterozygous individuals
reproduction occurs between organisms that have no distinct family ties.
Balanced polymorphism
a situation in which two different versions of a gene are maintained in a population of organisms because individuals carrying both versions are better able to survive than those who have two copies of either version alone.
Molecular biology
the branch of biology that deals with the structure and function of the macromolecules (e.g., proteins and nucleic acids) essential to life.
Genetic variability
(1) The tendency of individual genetic characteristics in a population to vary from one another.

(2) The potential of a genotype to change or deviate when exposed to environmental or genetic factors.
The role of adaptations in evolution
Adaptions evolve an organism to make it better for its enviornment
The role of variation in evolution
variation helps organisms differ so that organisms will evolve in different ways
The role of reproductive success in evolution
reproductive success will be if a species continues or not and how strong that species is
The role of heritability in evolution
if the offspring inherits the traits that will keep it alive from natural selection
The role of time in evolution