L1 - Introduction to Evolution, Biodiversity and deep time

Question 1

What are the six propositions of neo-darwinian theory?

Answer 1

1. Reproduction
2. Excess
3. Variation
4. Environmental selection (Natural Selection)
5. Divergence
6. Ancestry

Question 2

What is biodiversity?

Answer 2

Biodiversity is the variety of life, in all its manifestations. It encompasses all forms, levels and combinations of natural variation

Question 3

What is taxonomy?

Answer 3

It is the science of classification of organisms.

Question 4

What is Phylogeny?

Answer 4

Phylogeny is the study of evolutionary relationships.

Question 5

What is deep time?

Question 6

Is the fossil record complete?

Answer 6

It is incomplete and highly biased

Question 7

Why is the fossil record incomplete?

Answer 7

• Very few of the organisms that ever live will end up being fossilized (and ultimately collected and studied);
• Entire species or higher taxa may not be preserved in the fossil record. This is particularly true for those:-
  1. with low preservation potential
  2. with small population
  3. that inhabit a small geographical area
  4. that lived for only a short period of time

Question 8

Why is the fossil record biased?

Answer 8

1/ Certain environments are more likely to be preserved than others, i.e. those with net deposition rather than net erosion. Thus:-
Marine organisms are more likely to be preserved than terrestrial organisms
Terrestrial lowland deposits (e.g. nearshore and floodplain) are more likely to be preserved than upland deposits
2/ fossils of aquatic organisms, or organisms that find their way into aquatic environments, are much more likely to be preserved.
3/ Organisms with recalcitrant, and therefore more readily preserved, tissues are more likely to be preserved (e.g. bone, tooth, wood, shell versus soft bodied organisms)

Question 9

Explain the environmental changes through time.

Answer 9

1. Spatially variable today
2. Temporarily variable
3. it has also changed over long periods of time or even over vast periods of deep time.
4. These changes can be long, medium or short - term.

Question 10

Give some examples of long term environmental changes through time.

Answer 10

• Solar luminosity
• Distance between the Earth and its moon (tides)
• Continental drift and plate tectonic events
• Changing atmosphere and climate change
• Milankovitch cycles
• The evolving biota

Question 11

Give some examples of short term and rare environmental changes through time.

Answer 11

• Large Igneous Provinces (LIPS)
• Short-medium term atmospheric/climate change
• Super eruptions
• Meteorite impacts
• Tsunamis
• Mass extinctions