Unit 4: Species, Variation and Speciation Flashcards
What are the 6 main concepts of species ?
1) Biological
2) Phylogenetically
3) Morphological
4) Ecological
5) Nominalism
6) Evolutionary significant units
What is a prezygotic barrier ?
Animals that have no chance to mate
What are the 4 main prezygotic isolation mechanisms that exist ?
- Geographical isolation
- Mechanical isolation
- Temporal isolation
- Behavioural isolation
What is a postzygotic barrier ?
Where there is incomplete fertilisation or infertile hybrids are produced
What are the 4 main postzygotic isolation mechanisms that exist ?
- Gamete incompatibility
- Hybrid mortality
- Hybrid breakdown (F2)
- Hybrid infertility (F1)
What is hybridisation ?
The formation of a new species or “extinction’ (Fusion) of 2 and more species
What are the 3 possible outcomes of hybridisation ?
- Reinforcement
- Fusion
- Stability
What is cladogenesis ?
Where a single species splits into two or more distinct species increasing biodiversity
What are the 6 features of speciation ?
- Variation
- Isolation
- Decreased gene flow
- Selection
- Divergence
- Speciation
What is the effect of point mutations near genes ?
- Change in proteins
- Change of gene regulation
What is the effect of duplications or deletions of genes ?
- Gene dose
- Formation of new genes
What is the effect of insertion of mobile elements in genes ?
- Gene regulation
- Protein structure
What are the 3 main sources of genetic variation at chromosome level ?
- Recombination
- Segregation
- Independent assortment
What is allopatric speciation ?
Speciation by geographical isolation that often has barriers that prevent two or more populations from mating
What is vicariance ?
The process by which a geographical barrier (such as a river) divides a population leading to speciation
What is dispersal ?
The movement of species from one location to another leading to the establishment of new populations
What is sympatric speciation ?
Where new species evolve from a single ancestral species while inhabiting the same geographical range
What is polymorphism ?
Different phenotypes or forms in a population
What is peripatric/parapatric speciation ?
Small peripheral populations which exploit a different niche
What mechanism of speciation is similar to peripatric speciation ?
Allopatric speciation
What mechanism of speciation is similar to parapatric speciation ?
Sympatric speciation
What is a ring species ?
A series of neighbouring populations, each can interbreed with its close neighbours but the end populations don’t produce fertile hybrids
What is an ecological niche ?
It is the role the species plays in an ecosystem and includes the type of food it eats, where it lives, where it reproduces and its relationships with other species
Can two species occupy the same ecological niche ?
NO TWO SPECIES CAN OCCUPY THE SAME ECOLOGICAL NICHE
What is a fundamental (theoretical) niche ?
The full range of environmental conditions and resources an organism can possibly occupy and use without limiting factors
What is a realised (actual) niche ?
Part of fundamental niche that an organism occupies as a result of limiting factors present
What is a genes unit of evolution ?
Unit of heredity
What is a cell’s unit of evolution ?
Unit of development
What is an individuals unit of evolution ?
Unit of natural selection
What is a populations unit of evolution ?
Unit of speciation
What is a species unit of evolution ?
Unit of phylogeny
