The Fundamental Aspects of Evolution
The three key “ingredients” necessary for evolution to occur:
- Variation
- Time
- Selection
Chapter summary:
1. Size:
- Macro evolution
- Micro evolution
2. Patterns:
- Anagenesis
- Cladogenesis
- Adaptive Radiation
3. Rates:
- Gradualism
- Punctuated Equilibrium
4. Mechanisms:
1. Natural selection
2. Polyploidy
3. Mutations
4. Gene flow
5. Genetic drift
5. Artificial selection
,Macroevolution
= the change that occurs at or above the level of species over long periods of time.
Trends:
- Increased complexity
- e.g. Prokaryotes to eukaryotes or primitive societies to the emergence of human societies.
- Increasing body size and cranial capacity
- e.g. Horses or hominids
- Evolving from marine habitats then to terrestrial habitats, before evolving the ability to fly.
Microevolution
= smaller evolutionary changes (typically changes in allele frequencies) within a species or a
= population - much quicker process.
Phylogeny - the scientific study of evolutionary relationships among species.
Can be represented in a phylogenetic tree.
The trunk and stems are the lineages of ancestors.
The branching points represent divergences between linages.
The tips of the branches represent living species (or extinct species that died without
descendants)
Phylogenetics - the study of evolutionary relationships among groups of organisms which have
been discovered through the lines of evidence
, Phylogenetic trees and Cladograms
Graphical representation of evolutionary relationship (relatedness) between taxonomic groups.
Each node with descendants represents the most recent common ancestor of the descendants.
Branch lengths may be proportional to predicted evolutionary time between organisms.
Do not clarify the pathway that created existing relationships.
The three key “ingredients” necessary for evolution to occur:
- Variation
- Time
- Selection
Chapter summary:
1. Size:
- Macro evolution
- Micro evolution
2. Patterns:
- Anagenesis
- Cladogenesis
- Adaptive Radiation
3. Rates:
- Gradualism
- Punctuated Equilibrium
4. Mechanisms:
1. Natural selection
2. Polyploidy
3. Mutations
4. Gene flow
5. Genetic drift
5. Artificial selection
,Macroevolution
= the change that occurs at or above the level of species over long periods of time.
Trends:
- Increased complexity
- e.g. Prokaryotes to eukaryotes or primitive societies to the emergence of human societies.
- Increasing body size and cranial capacity
- e.g. Horses or hominids
- Evolving from marine habitats then to terrestrial habitats, before evolving the ability to fly.
Microevolution
= smaller evolutionary changes (typically changes in allele frequencies) within a species or a
= population - much quicker process.
Phylogeny - the scientific study of evolutionary relationships among species.
Can be represented in a phylogenetic tree.
The trunk and stems are the lineages of ancestors.
The branching points represent divergences between linages.
The tips of the branches represent living species (or extinct species that died without
descendants)
Phylogenetics - the study of evolutionary relationships among groups of organisms which have
been discovered through the lines of evidence
, Phylogenetic trees and Cladograms
Graphical representation of evolutionary relationship (relatedness) between taxonomic groups.
Each node with descendants represents the most recent common ancestor of the descendants.
Branch lengths may be proportional to predicted evolutionary time between organisms.
Do not clarify the pathway that created existing relationships.
