Evolution Flashcards
(24 cards)
Natural Selection
not the sole mechanism for evolution, but for adaptation
Gene Pool
Collection of alleles in the population
Allele frequency
How common that allele is in the population
Mendel’s 1st Law of Inheritance
The Law of Segregation- When an individual produces gametes, the two copies of gene separate, so that each gamete receives only one copy per parent
Population Genetics
Selective forces change a population through changes in allele and genotype frequencies
5 forces of evolution
Genetic Variation, Natural Selection, Non-random mating, gene flow, mutation
Mendel’s 2nd Law of Inheritance
The Law of Independent Assortment- Allele of different genes separate independently during gamete formation if they are on different chromosomes
Genetic Variation
random change in allele frequencies
Founder Effect
Small amount of individuals creates a new population
Population bottleneck
Disaster causes a steep drop in population size
What population size does genetic drift affect the most?
Small Populations
Phylogeny
Evolutionary history and relationship of an organism or groups of organisms
Branch Point
point where a split occurs, where a single lineage evolved into a distinct one
Homologous Structures
Features that overlap morphologically and genetically, but have different functions
Analogy
Similar characteristics occur because of environmental constraints and not due to close evolutionary relationships
Clades
groups of organisms that descended from a single ancestor
How do we date historical events?
Radioactive Isotopes, C-14
Cambrian Explosion
Most of major phyla of today originated, oxygen in atmosphere
Phylogeny
A model of evolutionary relationships based on data
Convergent Evolution
Independent evolution of similar features in species of different times
Polyphyletic
Derived from more than one common ancestor, so not suitable for the same taxon
Monophyletic
A group of organisms that are more closely related to each other than the other species
Paraphyletic
Descended from a common ancestor, but not including all descendent groups
Three necessary conditions for natural selection
Variability in traits, heredity, selection for advantageous traits
