Biol 114 Week 1: Introduction to Evolution

Evolution

the change in genetic (allelic) frequency within a population over time

Natural Selection

a process by which evolution can occur

What does natural selection require?

Trait variation in a population, Heritability, Differential survival, Differential reproduction

Adaptation

A heritable trait that increases the relative fitness of individuals having the trait

Microevolution

the change in a population over generations that helps to separate populations from each other genetically

Macroevolution

the accumulation of microevolution over a long period may result in the creation of new species

Genetic Homology

similar gene sequences between individuals of different species

Developmental Homology

similarities in morphology of embryos of different species

Structural Homology

similarities in structure of body parts of different species

Similarities in structure of body parts of different species

An increase in multicellularity, an increase in complexity, an increase in ways to capture energy for use, an increase in ways to deal with the environment-biotic and abiotic, an increase in diversity (snowball effect)

Heritability

passed down from parent to offspring by genes

Differential Survival

refers to differences in the persistence of genes (traits) across time within a genetic line within a population

Differential Reproduction

as a result of a condition of the trait, individuals will have more breeding opffspring than others, thus passing the genes for that condition into the next generation

Jean Baptiste de Lamarck

1. Species have changed over time

2. Simple organisms spontaneously generated

3. Species change throughout time via acquired characteristics

Darwin’s Theory on the Origin of Species by Natural Selection (3 componnents)

1. All species have a common ancestor

2. All species show changes in characteristics through time

3. All species show changes in characteristics in different environments

Artificial Selection

the selective pressure is not occurring as a result of non-human environmental
conditions, and, more importantly, the resulting desirable traits do not necessarily allow the individuals to survive and reproduce more offspring in the wild

Evolutionary Theory

1. Species are related

2. Species (and species diversity) changes over time

3. Evolution should be able to be seen in the short-term

Evolutionary trends

1. An increase in multicellularity

2. An increase in complexity

3. An increase in ways to capture energy for use

4. An increase in ways to deal with the environment-biotic and abiotic

5. An increase in diversity (snowball effect)