FUNDAMENTAL ASPECTS OF EVOLUTION
Macroevolution:
Macroevolution is the change that occurs at or above the level of species over long periods of time
- Includes the remarkable trends and transformations in evolution
- Not easy to see macro-evolution history
- Lines of evidence = Molecular sequencing data, geology, fossils and living
organisms
Phylogeny: scientific study of evolutionary relationships among species
Phylogenetics: study of evolutionary relationships among groups of organisms which have been
discovered through the lines of evidence
Phylogeny can be represented in a phylogenetic tree
• Trunk and stems are lineages of ancestors
• Branching points representing divergences between lineages
• Tips of branches are living species (or extinct species that dies without
descendants)
What is the tree of life?
A metaphor describing relationships of all life on Earth in an evolutionary context
What are some patterns that are repeated in the tree of life?
1) Stasis/equilibrium
o Means they don’t show change much for a long time
o Changed so little they called living fossils
o Coelacanth is an example
2) Lineage-splitting/speciation
o Can be shown by constructing and examining a phylogeny
o Might show cladogenesis or anagenesis
Cladogenesis: is an evolutionary splitting event where a parent species splits into two distinct
species, forming a clade
o A clade is a life-form group consisting of a common ancestor and all its
descendants
, FUNDAMENTAL ASPECTS OF EVOLUTION
o In anagenesis the ancestral species gradually accumulates changes, and
eventually, when enough is accumulated, the species is sufficiently distinct
and different enough from original
o Palaeontologists see role of cladogenesis as more NB in evolution to that of
anagenesis
Macroevolution:
Macroevolution is the change that occurs at or above the level of species over long periods of time
- Includes the remarkable trends and transformations in evolution
- Not easy to see macro-evolution history
- Lines of evidence = Molecular sequencing data, geology, fossils and living
organisms
Phylogeny: scientific study of evolutionary relationships among species
Phylogenetics: study of evolutionary relationships among groups of organisms which have been
discovered through the lines of evidence
Phylogeny can be represented in a phylogenetic tree
• Trunk and stems are lineages of ancestors
• Branching points representing divergences between lineages
• Tips of branches are living species (or extinct species that dies without
descendants)
What is the tree of life?
A metaphor describing relationships of all life on Earth in an evolutionary context
What are some patterns that are repeated in the tree of life?
1) Stasis/equilibrium
o Means they don’t show change much for a long time
o Changed so little they called living fossils
o Coelacanth is an example
2) Lineage-splitting/speciation
o Can be shown by constructing and examining a phylogeny
o Might show cladogenesis or anagenesis
Cladogenesis: is an evolutionary splitting event where a parent species splits into two distinct
species, forming a clade
o A clade is a life-form group consisting of a common ancestor and all its
descendants
, FUNDAMENTAL ASPECTS OF EVOLUTION
o In anagenesis the ancestral species gradually accumulates changes, and
eventually, when enough is accumulated, the species is sufficiently distinct
and different enough from original
o Palaeontologists see role of cladogenesis as more NB in evolution to that of
anagenesis
