Lecture 1

Is mutation random in nature

yes

Is natural selection random or directional

directional

gene flow

is random or directional

• occurs when there is a random change in the frequency of alleles in a population

genetic drift

also random

• the movement of genetic material from one population to another 

Factors necessary for natural selection to work

1. Variation in a population

2. Genes must be heritable

3. Differential reproduction

macro and micro evolution

Difficult to get the whole evo scale of 4 billion years

Typological species concept

describes them as immutable, has to have an archetype of the species

• It is prevolutionary

• species are static and unchanging/unmutable 

• There is an ideal individual, and any variation would lead to negative influences to the environment 

Morphological species concept

takes evolutionary history into account (most practical)

• it is post evolutionary 

• it is based on gross morphologies 

• variations occur naturally, not due to negative consequences of the environment

Biological species concept

• Based of reproduction and who can reproduce with each other

• The one that is discussed the most (bias towards animals)

• Offspring is fertile 

Phylogenetic species concept

Individual species that can form a clade and share a common ancestor

Ecological species concept

• Two species cannot occupy the same ecological niche

allopatric speciation

groups from an ancestral population evolve into separate species due to a period of geographical separation

In sympatric speciation

groups from the same ancestral population evolve into separate species without any geographical separation

Types of Natural Selection

Directional: favours one extreme trait

Stabilizing: favours average trait

Disruptive: favours both extremes