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chapter 25 and 24 bio vocab

Terms in this set (49)

Macroevolution
Evolutionary changes that create new species/groups of species
Species
A group of organisms that maintains a
distinctive set of attributes in nature • ~1.75 million identified
• Estimates of 5 to 50 million
Morphological Traits
Based on physical characteristics
Reproductive Isolation
Prevents one species from successfully interbreeding with other species
Molecular Features
Comparison of features that identify similarities
and differences among different populations
Ecological Factors
Factors related to organism's habitat used to distinguish one species from another
Species concepts
Way to define the concept of a species
Biological Species Concept (BSC)
A group of individuals that have the potential
to interbreed to produce viable, fertile offspring
• Cannot successfully interbreed with
members of other species
• Reproductive isolation is key
Evolutionary Lineage Concept (ELC)
Species derived from a single lineage
• distinct from other lineages
Ecological Species Concept
Each species occupies an ecological niche
Reproductive Isolating Mechanisms (Process)
Prevent interbreeding between different species
Habitat Isolation
Geographic barrier
Temporal isolation
Reproduce at different times of the day/year
Mechanical isolation
Size or incompatible genitalia prevents
mating
Behavioral isolation
Behaviors important in mate choice • Changes in song
Gametic isolation
Gametes fail to unite successfully .
• Important in species that release
gametes into the water or air
Hybrid inviability -
fertilized egg cannot progress past early embryo
Hybrid sterility -
hybrid viable but sterile
Hybrid breakdown -
hybrids fertile but later generations = genetic abnormalities
Speciation
Formation of a new species
Cladogenesis
Division of a species into 2 or more species
Allopatric speciation
Most common method of cladogenesis . • Occurs when populations become
geographically separated
Adaptive radiation
single species evolves into many
• differ greatly in habitat, form or behavior
Hybrid zone
Zone where two populations can interbreed
Sympatric speciation
When members of a species within the same
environment diverge into two or more different species
• no physical barriers to interbreeding
Polyploidy
Organism has 2 or more sets of chromosomes
Adaptation to local environments
Geographic area may have variation
Sexual selection
Certain females prefer males with one color
pattern, while other females prefer males with a different color pattern
Gradualism
Each new species evolves continuously over
long spans of time
Punctuated equilibrium
Tempo more sporadic
• Species in equilibrium for long periods and
then short rapid bursts of changes
Population Genetics
Study of genes and genotypes in a population
Population
Group of individuals of the same species that occupy the same environment and can interbreed with one another natural selection
Gene pool
All of the alleles for every gene in a given population
Microevolution
Changes in a population's gene pool from generation to generation
natural selection
Process in which heritable beneficial traits become more common in successive generations
Reproductive success
Likelihood of an individual contributing fertile offspring to the next generation
Stabilizing selection
Favors the survival of individuals with intermediate phenotypes
Directional selection
Individuals at one extreme of a phenotypic range have greater reproductive success in a particular environment
Disruptive/Diversifying selection
Favors the survival of two or more different genotypes that produce different phenotypes
Balancing selection
Maintains genetic diversity
Sexual selection
-Form of natural selection
• Directed at certain traits of sexually reproducing species
• make it more likely for individuals to find or choose a mate and/or engage in successful mating
Intrasexual selection
Between members of the same sex
Intersexual selection
Between members of the
opposite sex
• Female choice
Genetic drift
Changes allele frequency due to random chance
Migration
Gene flow occurs when individuals migrate
between populations having different allele freqs.
Nonrandom mating
Individuals choose their mates irrespective of their genotypes and phenotypes
assortative mating
Individuals with similar
phenotypes are more likely to mate (Favors homozygosity)
disassortative mating
Dissimilar phenotypes mate preferentially (Favors heterozygosity) more wild and wacky
Inbreeding
Choice of mate based on genetic history (Favors no allele)
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