Download Exam 4 - Chapter 26 | BIOL 200A - Cell&Mol Biol Genet&Evol and more Quizzes Biology in PDF only on Docsity!
Speciation
The origin of new species, is at the focal point of evolutionary theoryOccurs in the absence of gene flow TERM 2
Species
DEFINITION 2 A population or group of populations whose members have the potential to interbreed with one another in nature and to produce viable, fertile offspring, but cannot produce viable, fertile offspring with members of another species TERM 3
Biological Species Concept
DEFINITION 3 Populations are evolutionarily independent if they are reproductively isolated from each other TERM 4
Reproductive Isolation
DEFINITION 4 A new species will formThe existence of biological factors (barriers) that prevent two individuals of a species from mating and producing viable and fertile offspring TERM 5
Prezygotic Isolation
DEFINITION 5 Occurs when individuals of different species are prevented from matingHabitat isolationTemporal isolationBehavioral isolationMechanical isolationGametes isolation
Postzygotic isolation
Occurs when individuals from different populations do mate, but the offspring produced have low fitness and do not survive or produce offspringHybrid SterilityHybrid Viability TERM 7
Habitat Isolation
DEFINITION 7 Two species living in different habitats within the same area may encounter each other rarely TERM 8
Temporal Isolation
DEFINITION 8 Two species that breed at different times of the day, seasons, or years do not mix gametes TERM 9
Gametic Isolation
DEFINITION 9 Gametes of different species that meet rarely fuse to form a zygote, but it may not survive in the female internal environment TERM 10
Behavioral Isolation
DEFINITION 10 Patterns of courtships may be altered to the extent that sexual union is not achieved
Monophyletic group (clade)
Phylogenetic trees that show the ancestral population plus all of its descendants TERM 17
Subspecies
DEFINITION 17 Populations that live in discrete geographic areas and have their own identifying traits but are not distinct enough to be considered a separate species TERM 18
What are the two mechanisms of the origin of
speciation?
DEFINITION 18 Genetic isolation and geographical isolation TERM 19
Allopatric speciation
DEFINITION 19 Involves a geographic barrier that allows a new species to evolve because gene flow is interruptedDispersal and Vicariance TERM 20
Dispersal
DEFINITION 20 A population moves to a new habitat, colonizes it, and forms a new population
Vicariance
A physical barrier splits a widespread population into subgroups that are physically isolated from each other TERM 22
Sympatric Speciation
DEFINITION 22 Speciation take place in geographically overlapping populationsReproductive isolation evolves without geographical isolationNatural selection overcomes gene flow and cause sympatric speciation TERM 23
Polyploidy
DEFINITION 23 The condition of having more than two sets of chromosomesCan cause speciationIndividuals are reproductively isolated , evolutionary independent from original diploid populationMuch more common in plants than animals TERM 24
Autopolyploid
DEFINITION 24 An individual with more than two chromosome sets, derived from one species TERM 25
Allopolyploid
DEFINITION 25 A species with multiple sets of chromosomes derived from different species
