Lecture 21: Species, Speciation & Hybridization Flashcards
What is microevolution?
Changes within a species/small group of organisms
What are some sources of microevolution?
Natural selection, genetic drift, mutation and migration
What is a species?
Traditionally defined by phenotypic similarity
What does sympatric mean
Within a region
What does allopatric mean
Across regions
What does taxonomic or morphological organisms mean?
On distinct measurable differences
What does biological organisms mean?
Based on inter-fertility among individuals
What is the Biological Species Concept?
1) Geographical isolation alone is not enough
2) Possible interbreeding in the wild
Why is the weakness of Biological Species Concept?
Does not apply well for bacteria, asexuals, highly self-fertilizing species or fossils
Where does speciation more commonly occur?
Allopatric speciation (species that are isolated) due to minimal gene flow
What are the stages of reproduction isolation (RI)
1) Finding a compatible mate
2) Fertilization
3) Development and growth of zygote
4) Adult survival and reproduction
5) Growth, survival and reproduction of offspring
What stages of reproduction isolation are pre-zygotic isolation?
1) Finding compatible mat
2) Fertilization
3) Development and growth of zygote
What stage of reproduction isolation are post-zygotic isolation?
4) Adult survival and reproduction
5) Growth, survival, reproduction of offspring
What are pre-zygotic barriers?
Prevent mating or fertilization so no zygote gets formed
What are some examples of pre-zygotic barriers?
1) Geographical
2) Ecological
3) Temporal
4) Behavioural
5) Sexual mechanism (different genital structure compatibility)
4) Cellular (sperm-egg compatibility)
What factors pre-zygotic isolate in Apple Maggot flies and Hawthorn Flies?
Habitat and temporal isolation
- Different timing of fly mating on a preferred host plant
What factors pre-zygotic isolate Abalone?
Cellular
- Requires certain sperm lysin protein to fertilize egg
What are post-zygotic barriers?
Prevent proper functioning of zygotes once they are formed
What are the two types of post-zygotic barriers?
1) Intrinsic
2) Extrinsic
What is intrinsic post-zygotic barrier?
Not being capable of surviving, producing children or abnormal development of hybrids
What is extrinsic post-zygotic barrier?
Ecological mismatch of hybrid phenotype to environment
What is an example of intrinsic post-zygotic?
Mules, a sterile hybrid between male donkey and female horse
What is an example of extrinsic post-zygotic?
A species of butterfly that are bright in colour. This results in high predator and lower mating success
What is adaptive radiation?
The evolution of ecological and phenotypic diversity within a rapidly multiplying linage as a result of speciation
What are four common features to identify an adaptive radiation?
1) Recent common ancestry from a single species
2) Phenotype-environment correlation
3) Trait utility
4) Rapid speciation
What is an example of adaptive radiation?
Darwin’s finches
What causes Adaptive Radiation?
1) Ecological Opportunity
2) Origin of key innovation
3)High rates of speciation characterize the clade
What is polyploidy
Organism, tissue or cell with more than two complete sets of homologous chromosomes
What is an example of allopolyploidy?
Duplicated chromosomes of hybridization between species
What is an example of autopolyploidy?
Duplicated chromosomes within a species
