Lecture 1: Introduction to Evolution, Biodiversity and Deep Time Flashcards
Neo-Darwinian theory can be summarised in 6 propositions:
- Reproduction
- Excess
- Variation
- Environmental selection (natural selection)
- Divergence
- Ancestry
Biodiversity is…
the variety of life, in all its manifestations.
Taxonomy is…
the science of classification of organisms
Phylogeny is…
the study of evolutionary relationships
Almost universally agreed that evolution occurs via
net-darwinian evolution.
Phanerozoic periods (oldest to newest)
Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Paleogene Neogene Quaternary
Taxonomic Hierarchy (D King Philip Came Over For Good Spaghetti)
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
How old is earth
4.6 billion years old
Myr
Million years
Studying biodiversity; extant organisms
Easy!
- use DNA to compare
- they’re present you can easily study them
Studying biodiversity; the fossil record (extant and extinct organisms)
-incomplete and highly biased!
Fossil record is incomplete because :
- very few of the organisms that ever live will end up being fossilised
- entire species or higher taxa may not be preserved in the fossil record. This is particularly true for those:
a) with low preservation potential
b) with small population
c) that inhabit a small geographical area
d) that lived for only a short period of time
Fossil record is biased because:
- certain environments are more likely to be preserved than others;
a) Marine organisms more likely to be preserved than terrestrial organisms
b) Terrestrial low land deposits (nearshore marine and floodplain) more likely to be preserved than upland deposits - Aquatic organisms (or organisms that find their way into aquatic conditions) are more likely to be preserved
- organisms with recalcitrant and therefore more readily preserved tissues are more likely to be preserved. (e.g. bones, wood,shells vs soft bodied organisms)
Environment of planet earth is both
spatially (sahara, arctic) and temporally variable (Diurnal seasons)
Earth also changes over long period of time such as
milankovitch cycles and even over vast periods of deep time
