156 terms

AP Bio Unit 1

Scala naturae
Aristotle's view of organization of species
layers of sediment
study of fossils
the principle that events in the past occurred suddenly and were caused by mechanisms different from those operating in the present
mechanisms of change are constant over time
use and disuse
lyell's idea that parts of the body that are used become larger and those that are not used deteriorate
characteristic that enhances survival and reproduction in specific environments
natural selection
individuals with certain inherited traits leave more offspring than others
descent with modification
darwin's term for evolution
artificial selection
humans selectively breeding individuals that possess desired traits
similarity resulting from common ancestry
homologous structures
variations on a structural theme present in a common ancestor
vestigial structures
remnants of features that served important functions in organisms' ancestors
convergent evolution
the independent evolution of similar features in different lineages
geographic distribution of species
continental drift
the slow movement of earth's continents over time
found nowhere else in the world
the study of change in allele frequencies in a population over generations
average heterozygosity
the average percent of loci that are heterozygous
discrete characteristics
characteristics classified on an "either-or" basis
quantitative characteristics
characteristics that vary along a continuum
nucleotide variability
differences in nucleotide arrangement
gene variability
differences in genes
geographic variation
differences in the genetic composition of separate populations
a change in the nucleotide sequence of an organism's dna
hardy weinberg principle
the frequencies of alleles and genotypes in a population will remain constant provided only mendelian segregation and recombination of alleles
genetic drift
chance events causing allele frequencies to fluctuate unpredictably from one generation to the next
founder effect
when a few individuals become isolated from a larger population, their gene pool differs from the source population
bottleneck effect
after a severe drop in population size, the resultant population has a differing gene pool from that of the source population
gene flow
transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes
relative fitness
the contribution an individual makes to the gene pool relative to the contribution of other individuals
directional selection
conditions favor individuals exhibiting one extreme of the phenotypic range
disruptive selection
conditions favor individuals at both extremes of the phenotypic range
stabilizing selection
conditions favors individuals at the intermediates of the phenotypic range
sexual selection
individuals with certain inherited characteristics are more likely than other individuals to obtain mates
sexual dimorphism
marked differences between the two sexes in secondary sexual characteristics
intrasexual selection
individuals of one sex compete directly for mates of the opposite sex
intersexual selection
individuals of one sex are choosy in selecting their mates of the other sex
balancing selection
natural selection maintains two or more forms in a population
heterozygote advantage
individuals who are heterozygous at particular alleles have a greater fitness than both homozygotes
frequency-dependent selection
the fitness of a phenotype declines if it becomes too common in a population
neutral variation
nucleotide differences conferring no selective advantage or disadvantage
the broad pattern of evolution over long time spans
biological species concept
a species is defined as a group of populations that can interbreed to produce viable, fertile offspring but cannot do this with members of other group
reproductive isolation
the existence of biological barriers that impede members of two species from producing viable, fertile offspring
offspring that result from interspecific mating
prezygotic barriers
barriers that block fertilization from occuring
postzygotic barriers
barriers that contribute to reproductive isolation after the zygote is formed
habitat isolation
two species occupy different habitats (prezygotic barrier)
temporal isolation
species breed during different times (prezygotic barrier)
behavioral isolation
courtship rituals unique to a species (prezygotic barrier)
mechanical isolation
morphological differences (prezygotic barrier)
gametic isolation
sperm of one species cannot fertilize eggs of another species (prezygotic barrier)
reduced hybrid viability
hybrid's development or survival is impaired (postzygotic barrier)
reduced hybrid fertility
hybrids are sterile (postzygotic barrier)
hybrid breakdown
hybrids offspring are feeble or sterile (postzygotic barrier)
morphological species concept
characterizes species based on body shape and structural features
ecological species concept
characterizes species based on ecological niche
phylogenetic species concept
characterized species based on the smallest group of individuals that share a common ancestor
allopatric speciation
gene flow is interrupted when a population is divided into geographically isolated subpopulations, causing speciation
sympatric speciation
speciation occurs in populations that live in the same geographic area
a species originating from accident in cell division that causes extra set of chromosomes
an individual that has more than two chromosome sets that are all derived from a single species
a viable fertile hybrid with one species that mated having meiotic error
hybrid zone
the region in which members of different species meet and mate
strengthening of reproductive barriers; hybrid gradually cease to be formed
weakening of reproductive barriers; the two species fuse
continued production of hybrid individuals
punctuated equilibria
period of apparent statis punctuated by sudden change
collections of abiotically produced molecules surrounded by a membrane like structure
rna catalysts that can synthesize proteins and carry out catalytic functions
radiometric dating
dating based on the decay of radioactive isotopes
half life
the time required for one 50% of the parent isotope to decay
layered rocks that form when certain prokaryotes bind thin films of sediment together
mitochondria and plastids were formerly small prokaryotes that bean living within larger cells
serial endosymbiosis
mitochondria evolved before plastids
first eon
second eon
third eon
first era
second era
third era
adaptive radiation
period of evolutionary change in which groups of organisms form many new species
an evolutionary change in the rate of development
mature species have body features prevalent in the juveniles of an ancestral species
homeotic genes
master genes that regulate where structures are positioned
the evolutionary history of species
a discipline focused on classifying organisms and determining evolutionary relationships
binomial nomenclature
system of two part names of species
the first part of the name of a species
phylogenetic tree
a branching diagram of the evolutionary history of a group of species
taxonomy through phylogeny
branch points
dichotomies that represents divergences of evolutionary lineages
sister taxa
groups of organisms that share an immediate common ancestor
a branch point from which more than two descendant groups emerge
a branch point within the tree represents the last common ancestor of all taxa
a structural similarity due to convergence
molecular systematic
the discipline that uses dna and other molecular data to determine evolutionary relationships
monophyletic group
consists of an ancestral species and all of its descendants
paraphyletic group
consists of an ancestral species and some, but not all, of its descendants
polyphyletic group
consists of members having different ancestors
shared ancestral character
a character that originated in an ancestor of the taxon
shared derived character
a character unique to the taxon
a species from an evolutionary lineage that is known to have diverged before the group of studied species
maximum parsimony
investigating the simplest explanation for the facts
maximum likelihood
a tree found that reflects the most likely sequence of evolutionary events
phylogenetic bracketing
predicting that features shared by two groups of closely related organisms are present in their common ancestor
orthologous genes
homologus genes found in different species because of speciation
paralagous genes
genes that result from gene duplication
molecular clock
a yardstick for measuring the absolute time of evolutionary change based on the observation that some genes change more rapidly than others
neutral theory
much evolutionary change has no effect on fitness and is not influenced by darwinian selection
horizontal gene transfer
a process in which genes are transferred from one genome to another
study of how animals behave in their natural environments
proximate causation
how a behavior occurs
ultimate causation
why a behavior occurs
behavioral ecology
the study of the ecological and evolutionary basis of animal behavior
fixed action pattern
a sequence of unlearned acts that is unchangeable and carried to completion when triggered
sign stimulus
trigger for a fixed action pattern
a change in activity as a response to a stimulus
an oriented movement towards or away from a stimulus
a regular, long distance change in location
a stimulus transmitted from one animal to another
transmission and reception of signals
chemical substance signals
innate behavior
behavior that is developmentally fixed
modification of behavior through experience
loss of responsiveness to a stimulus
the formation of a long-lasting behavioral response to a particular object or individual
sensitive period
a limited developmental phase when certain behaviors can be learned
spatial learning
the establishment of memory that reflects the organisms spatial structure
location indicators
cognitive map
a representation of the spatial relationships between objects in an animal's surroundings
associative learning
associating one environmental feature with another
classical conditioning
an arbitrary stimulus becomes associated with a particular outcome
operant conditioning
trial and error learning
the process of knowing represented by awareness, reasoning, recollection and judgement
problem solving
the cognitive capacity of devising a method to proceed from one state to or another in the face of an obstacle
cross fostering study
the young of one species are placed in the care of adults from another species
twin study
researchers compare the behavior of identical twins raised apart in different households
optimal foraging model
natural selection maximizes the benefits and minimizes costs of foraging
mating with no strong pair bonds or lasting relationship
one male mates with one female
an individual of one sex having multiple mates
one male has many female mates
one female has many male mates
agonistic behavior
ritualized contest that determines which competitor gains access to a resource
inclusive fitness
the total effect an individual has on proliferating its own genes and by providing aid that enables close relatives to proliferate theirs
coefficient of relatedness
the fraction of genes that are shared
Hamilton's rule
kin selection
the natural selection that favors altruistic behavior by enhancing reproductive success of relatives
reciprocal altruism
exchange of aid of non related individuals
social learning
learning through observing others
a system of information transfer through social learning that influences the behavior of individuals in a population
mate-choice copying
a behavior in which individuals in a population copy the mate choice of others
the study whose premise is that certain behavioral characteristics exist because they are expressions of genes that have been perpetuated by natural selection