Patterns In Biodiversity

Question 1

What is latitudinal diversity gradient

Answer 1

The tendency for more species to occur towards the equator.
It is the dominant pattern of life on earth yet the mechanisms responsible for it remain largely unexplained.

Question 2

Example of proof of latitudinal diversity gradient

Answer 2

Fischer 1960, states that lake Malawi has 1450 freshwater fish species, while the great Bear lake in Canada only has 14 freshwater fish species.
Thus supporting the statement that biodiversity is higher closer to the equator.

Question 3

How abiotic and biotic interactions determine distribution of reed building coral

Answer 3

Biotic & abiotic factors interact to control species distribution.
All reef building corals photosynthetic dinoflagellates that live in coral tissue.
They live in symbiosis with coral.

Zooxanthellae are a biotic factor that limit eeed building corals distribution due to narrow abiotic requirements of the Zooxanthellae.

Question 4

What are abiotic requirement of Zooxanthellae

Answer 4

18-30°C temp
Need access to light.
Narrow salinity tolerance.

Question 5

How are coral reef ecosystems being affected by climate change.

Answer 5

Changes in water temp, salinity and light range can kill Zooxanthellae causing coral to expel them which causes bleaching.
Coral can’t survive w/out Zooxanthellae to provide food.

Factors triggering bleaching:
Increase/decrease water temps
Reduced pH
Pollution
Non-biodegradable chems (sunscreen)

Question 6

What is ideal free distribution

Answer 6

All individuals free to move into any habitat without constraints.
*diagram
Highest quality habitat occupied first.
When density reaches certain point in A, B becomes more suitable habitat & colonized.
As density of A & B increase habitat C is occupied.
When density is high and all habitats full, densities will vary between A B & C and suitability is equal.

Question 7

What is ideal despotic distribution

Answer 7

All individuals are not free to move between habitats & highest quality one is protected by territorial behavior.
*diagram
Subordinate individuals pushed to lower quality habitats.
Density on poorer habitats may be equal or higher to that in high quality habitat.
Fitness lower in poorer habitats.