Population Genetics and Evolution (Chemicals produced Chemosynthetically ,…
Population Genetics and Evolution
Deals with the abundance of a particular of different alleles within a population and the manner in which the abundance of particular alleles increase,decreases or remains the same.
The total number of alleles in all the sex cells of all individual of a population constituents
Factors affecting Gene pool
Because of mutation, existing alleles decrease in frequency,and new alleles increases.
Events to which an organism cannot adapt, such as the collision of a large meteorite of sufficient sizes strikes Earth, a large region of Earth's surface is destroyed.
The most siginificant factor causing gene pool changes, is usually described as a survival of fittest.
Condition for natural selection
The population must produce more off spring than can possibly grow and survive to maturity in that habitat.
Progeny must differ from each other in their types of alleles.
Natural selection has a caused a new species to evolve, a process called speciation.
This movement of alleles physically through space, called gene flow.
Pollen grains each carry one full haploid genome, and alleles of a plant are present in its pollen grains.
The fruits and seeds of some plants fall close to parent, but many species have long- distance dispersal mechanisms.
A species produces small, mobile pieces that reproduce vegetatively, these too contribute to gene flow.
Biological Reproductive Barriers
Any biological phenomenon that prevents successful gene flow is a biological reproductive barrier.
Any physical, non living feature that prevents two population from exchanging genes is called abiological reproductive.
If two distinct, unrelated species occupy the same or similar habitats, natural selection may favor the same phenotypes that resembles each otherstrongly
Evolution and The origin of life
Condition on before the origin of life
Time available for origin of life
Hydrogen is a light gas, most of the first atmosphere was lost into space and replaced by second atmosphere.
The early second atmosphere was a reducing atmosphere.
Chemicals produced Chemosynthetically
Aggregation and organization
Formation of Polymers
The presence of life