Process of Evolution Flashcards
Natural Selection
Tendency of organisms with favorable adaptations to their environment to survive and produce new generations
What is artificial selection used for?
To change agricultural and domestic plants and animals
Self-pollinating Plant
Fertilization regularly involving gene derived from the same plant
Cross-pollinating
Fertilization regularly involving gametes derived from different plants
Subspecies
geographically isolated from other members of its species, do not inbreed
Varieties
Group of plants within a species, not generally isolated from each other, distinguishing characteristics
Cultivar
Produced and maintained by humans
Hybrid
cross pollination of two varieties or species
developmental plasticity
directly due to environmental conditions
cline
change along and environmental gradient
ecotype
group of genetically distinct populations of the species
Mutations
change in gene or chromosome
- deletion, translocation, inversion
Migration
gene flow between populations
genetic drift
changes due to random events
Founder effect
population becomes separated
bottleneck effect
population reduced in numbers
Geographic isolation
- isolation prevents gene flow between two populations
- random mutations spread only throughout the population that they arise in
- genetic changes become great that gene flow can’t occur
Ecological isolation
- climate, soils, time, mechanical factors play a role
- results in sympatric species that occupy overlapping ranges of territories, that don’t exchange genes
What results in changes in chromosome number?
Mistakes during chromosome pairing and separation can result in gametes carrying extra/missing chromosomes
Aneuploid
carries 1+ extra chromosomes, or missing 1+ chromosomes
Polyploids
more than 2 sets of chromosomes
- result in failure of meiosis to halve chromosome number
Autopolyploids
Polyploid formed from the doubling of a single gene
Why are hybrids sterile?
The chromosomes do not pair properly at meisos
- if polyploid formed in hybrid, then chromosomes can pair and overcome sterility
Allopolyploid
polyploidy formed from the union of 2 separate chromosome sets and their subsequent doubling
Apomixis
production of seeds without fertilization
- sterile hybrids reproduce asexually
gene pool
sum of all the alleles of all the genes of all the individuals in the population
microevolution
small-scale generation-to-generation change in frequency of a population’s alleles
