Introduction to Evolution Flashcards
What are the six propositions of Neo-Darwinian?
1) Reproduction
2) Excess
3) Variation
4) Environmental selection (AKA natural selection)
5) Divergence
6) Ancestry
What is variation caused by? (In sexual reproducing species)
Independent segregation of chromosomes
Crossing over of alleles
Mutations
Give the short definition of biodiversity
The variety of life, in all its manifestations. It encompasses all forms, levels and combinations of natural variation
What is taxonomy?
The science of classification of organisms
What is phylogeny?
The study of evolutionary relationships
What are all the periods on Earth through time?
Quaternary
Neogene
Paleogene
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
How much of Earth’s history is Pre-Cambrian? What does this mean for multicellular organisms?
88%
Only 12% of Earth’s history is multi-cellular
Why is the fossil record incomplete?
1) Very few of organisms that ever lived will end up being fossilised
2) Entire species or higher taxa may not be preserved in the fossil record
Why is the fossil record biased?
1) Certain environments are more likely to be preserved than others e.g. ones with net deposition not net erosion
2) Fossils of aquatic organisms or organisms that find their way into aquatic environments are more likely to be preserved
3) Organisms with recalcitrant tissues are more likely to be preserved e.g. bone, tooth, wood, shells are more likely to be preserved but soft-bodied organisms will not be
What species may not be preserved in the fossil record and thus causing an incomplete fossil record?
Species with low preservation potential
Species with a small population
Species that inhabit a small geographical area
Species that lived only for a short period of time
How is the environment of plant Earth variable today?
Spatially and temporally variable
What can environmental changes be categorised into?
Long
Medium
Short-term
Extremely rare
Name some examples of long term environmental change through time
Solar luminosity (the sun gets brighter with age)
Distance between the Earth and its’ moon
Continental drift and plate tectonic events
Changing atmosphere and climate change
Milankovitch cycles
The evolving biota
What are some examples of short-medium term and rare events through time?
Large igneous provinces (LIPS)
Short-medium term atmospheric/climate change
Super eruptions
Meteorite impacts
Tsunamis
Mass extinctions
