Lecture Two - Distribution of organisms due to their environment

Question 1

Define a biome.

Answer 1

Ecosystems that share major similarities are called biomes.
For example, deserts and a tropical forests are both biomes — you have a general idea what their climates are like and what kinds of plants and animals would inhabit them.
Whether they are located in Africa or North America, the environmental conditions and community of organisms in a desert biome would share certain similarities.

Question 2

How does soil type effect distribution of organisms, what is the soil type in Australia?

Answer 2

Soil types (nutrients, grains etc.) will dictate which plants can grow in that area, and therefore which animals will live there who include those plants in their diet. 
Australian soil is very old and nutrient poor.

Question 3

How can we know how the distribution of organisms was like many years ago?

Answer 3

Palaeontology (fossils).
Palaeoecology (past vegetation).
Geology (plate tectonics, rock composition and isotopes).
Molecular genetics (modern phylo-genetics).
Distribution of pollen (very resistant to degradation due to sporopollenin).

Question 4

What is it about the CO2 levels at the moment that are worrying for climate change?

Answer 4

The rate at which CO2 is increasing, not the amount.

There have been times in history when CO2 levels have been much higher.

Question 5

What did the increase in O2 cause?

Answer 5

An increase in fires, due to the increase in the amount of vegetations (which converted the CO2 into O2) which can be combusted.
Also O2 is a reactant in combustion.