APS121 Evolution Flashcards
Defintion: Biodiversity
Is the variety of life, in all its manifestations. It encompasses all forms, levels and combinations of natural variation.
Defintion: Taxonomy
The science of the classification of organisms
Defintion: Phylogeny
The study of evolutionary relationships
What are the Phanerozoic time periods?
Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene.
(Camels often sit down carefully perhaps their joints creek permanently nowadays)
Reasons Why the fossil records is incomplete:
- Only of a few of the organisms to ever live will end up being fossilised and therefore studied.
- Entire species/taxa may not be at all preserved
What will limit chances of fossilisation?
- Low preservation potential
- Inhabit small geographical areas
- Small populations
- Only lived for a short period of time
How is fossilisation biased?
- Certain environments more likely to preserve organisms- ie marine> terrestrial, terrestrial lowland> terrestrial highland
- Aquatic animals or those who end up on aquatic environments better preserved
- Recalcitrant organisms more readily preserved
Defintion: Recalcitrant Organisms
Organisms with hard features like exoskeletons, bones, teeth.
Better preserved by fossilisation
Types of environmental change through time:
Temporarily Variable- Diurnal, Seasonl
Milankovitch Cycles- Relate to the earth rotating around sun, eg Icehouse or Greenhouse
Examples of long term environmental change:
- solar luminosity (getting brighter)
- decrease in tides as we move away from the moon
- continental drift
- evolving biota
Examples of short term environmental change:
- tsunamis
- super erosions
- mass extinctions
Order of Taxonomy
Kingdom, Phylum, Class, Order, Family, Genus, Species
Kinky pigs can only fly going sideways
Process: Cladistic Analysis
- Create a data matrix of character states for taxa under consideration
- Use a computer package to analyse the data and create a cladogram
(Dark spot means character is present, light spot means character is absent)
Defintion: Analogous
Similarity due to convergent evolution
aka homoplasy
Defintion: Homologous
Similarity due to common ancestry
Defintion: Symplesiomorphies
Shared ancestral characters (trait appeared in original ancestor)
Definition: Synapomorphies
Shared derived characters (trait appeared in most recent ancestor)
Definition: Autopomorphies
A derived character unique to a single taxon
Definition: Monophyletic Group
Contains the latest common ancestor plus all, and only all, of its descendants (Perfect group)
Definition: Paraphyletic Group
Diagnosed by plesiomorphs, doesn’t include all the descendants of a common ancestor (something was missed out)
Definition: Plesiomorphs
Homologous traits which are not unique to a group
Definition: Polyphyletic Group
A group where the most recent common ancestor is assigned to another group and not itself, due to convergence or non homologous characters assumed to have been absent. (added something wrong)
The eight system kingdom:
Bacteria, Archaea, Archaeozoa, Protista, Chromista, Animalia, Fungi, Plantae
The three domains:
Domain Bacteria, Domain Archaea, Domain Eukarya
Prokaryote and Eukaryote differences:
P: 1-10um, E: 10-100um in size
P: cell wall of peptides and sugars, E: cellulose and chitin
P: no membrane bound organelles E: membrane bound Mitochondria and Chloroplast
P: anaerobic E: aerobic
What do Prokaryotes split into
- Eubacteria
- Archaebacteria (less numerous and diverse, inhabit extreme environments)
> 3800 Ma
- Progress retarded by continued bombardment of large objects
- This releases energy sufficient enough to boil of oceans and the atmosphere
< 3800 Ma
- Meteorite bombardment decreases as they incorporate with different planets
- The planet begins to cool so oceans and the atmosphere condense out.
- Organic compounds begin synthesising an accumulating
Uses for the moon as a dead planet
- Can identify and date rock collisions from heavy bombardment
- This is because it is dead so nothing decomposes or changes
What formed the early atmosphere?
- volcanic outgassing of H2O, N2, CO2, CH4, NH3, H2, H2S
- Eventually this condenses into oceans and the earth becomes hospitable
Definition: Panspermia
The idea that life was seeded on earth by a comet or meteorite
Approaches to solving the Origin of Life
- Analyse living prokaryotes and attempt to reconstruct their common ancestor
- Compare duplicated genes, potentially enabling us to look back and estimate earliest components of genetic machinery
- Reconstruct conditions of previous earth and simulate experimentally to see what is produced