Chapter 10: Evolution Flashcards
Jean-Baptiste Lamarcks 2 ideas about evolution
- Use and Disuse
2. Inheritance of acquired characteristics
Evolution
The changes in populations, species, or groups of species.
Charles Darwin believed in:
Natural Selection
5 pieces of Evidence for Evolution
- Paleontology
- Biogeography
- Embryology
- Comparative Anatomy (Homologous and Analogous Structures)
- Molecular Biology
Molecular Biology
Examines the nucleotide and amino acid sequences of DNA and proteins from different species.
Comparative Anatomy
Describes the two kinds of structures that contribute to the identification of evolutionary relationships among species.
Homologous Structures
Body parts that resemble one another in different species because they have evolved from a common ancestor.
Analogous Structures
Body parts that resemble one another in different species, not because they have evolved from a common ancestor.
Embryology
Reveals Similar stages in development (ontogeny) among related species. The similarities help establish evolutionary relationships (phylogeny).
Paleontology
Provides fossils that reveal the prehistoric existence of extinct species.
Biogeography
Uses geography to describe the distribution of species. This information has revealed that unrelated species in different regions of the world look alike when found in similar environments.
Natural Selection
The differences in survival and reproduction among individuals in a population as a result of their interaction with the enviornment.
Stabilizing Selection
Eliminates individuals that have extreme or unusual traits.
___^^^___
Directional Selection
Favors traits that are at one extreme of a range of traits. Traits at the opposite extreme are selected against.
____^^^^^^
Insecticide resistance
Occurs as a result of directional selection. Eventually the whole population is insecticide resistant.
Disruptive selection
Occurs when the environment favors extreme or unusual traits, while selecting against the common traits.
^^^^_____^^^^
Sexual Selection
The differential mating of males (sometimes females) in a population.
- Male Competition
- Female Choice
Artificial Selection
A form of directional selection carried out by humans when they sow seeds or breed animals that possess desirable traits.
Mutations
Provide the raw material for new variation
5 Sources of Variation
- Mutations
- Sexual reproduction
- Diploidy
- Outbreeding
- Balanced Polymorphism
Diploidy
The presence of two copies of each chromosome in a cell. In the heterozygous condition, the recessive trait is “hidden”, and will provide a source of variation for future generations.
Outbreeding
Mating with unrelated partners, increases the possibility of mixing different alleles and creating new allele combinations.
Balanced Polymorphism
The maintenance of different phenotypes in a population
In Africa, the heterozygous pair for Haemophelia
Heterozygote advantage
Occurs when the heterozygote condition bears a greater selective advantage than either homozygous condition.
ex. Hemophilia (Heterozygote)
Hybrid Vigor/ Heterosis
The superior quality of offspring resulting from crosses between two different inbred strains of plants.