Lecture 2 Flashcards
Microevolution: Genetic Changes withing Populations
Evolution
genetic changes (decent modification) of a population over time
Biological Evolution
change in allele/genotype frequencies
Adaptive Radiation
organisms diversify rapidly due to the change in the environment (new resources available, new challenges created, new environmental niches opened…)
Microevolution
changes within species that are driven by natural selection (and other evolutionary forces), depends on heritable variation
Population
individuals of species at same time and place
Phenotypic Variation
heritable variation in appearance and/or function
Qualitative Variation
characteristics with distinct states, encoded by a small number of genes and can be easily placed into a specific category
Polymorphisms
distinct variants of character, the presence of two or more variant forms of a specific DNA sequence (e.g. presence of spines)
Quantitative Variation
characteristics with a range of variation, are controlled by multiple genes and can be measured (e.g. height), encoded by many different genes and can be placed on a continuum
New Alleles
(from mutations) occur in the reproductive cells and will passed on to the next generation
Recombination
from crossing over, independent assortment, random fertilization
Population Genetics
the study of patterns in genetic variation in populations
Population
a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring
The Gene Pool
the sum of all alleles at all gene loci (a fixed position on a chromosome) in all individuals within a population, characterizes a population’s genetic makeup, used to identify the genotypes and calculate genotype frequencies
Natural Selection
- only mechanism that leads to adaptations
- need genetic variation
- the variants best suited for growth and reproduction in a given environment contribute disproportionately to future generations
