Lecture 4 Flashcards
Microevolution
pertains to evolutionary changes in frequencies of variant forms of genes within populations
Macroevolution:
pertains to evolution on a long timescale. Origins of new structures, species, mass extinctions etc
Modern Synthesis
= Microevolution + Macroevolution
Patterns in macroevolution
- Stasis
- Lineage splitting
- extinction
Stasis
lineages don’t change much, even over millions of years (living fossils)
Lineage-splitting
• Various patterns
A. Frequent lineage splitting
B. low rate of lineage splitting
C. bursts of lineage splitting
Extinction
Can be frequent or rare
Two possible evolutionary fates for every species:
• give rise to new species
• become extinct.
Phylogeny:
The origin and diversification of any taxon, or the evolutionary history of its origin and diversification
Phylogenetic tree:
A tree diagram whose branches represent current or past evolutionary lineages and which shows the hypothesized patterns of common descent among those lineages
Classification is based on ________
common evolutionary descent
Homology:
character similarity resulting from common ancestry
Homoplasy:
non-homologous similarities that may be found in various organisms (not inherited from a common ancestor)
Cladistics
methodology for classifying organisms based on common evolutionary descent,
phylogeny that relates all extant and extinct species
Types of Clades
monophyletic clade
paraphyletic clade
polyphyletic clade
monophyletic clade:
includes the most recent common ancestor and all descendants of that ancestor
