Lecture 1- Global Patterns Of Biodiversity

Question 1

Define biodiversity

Answer 1

A measure of the VARIETY and VARIABILITY of life on earth. It is highly complex and has many attributes

Question 2

What is the most common way of measuring biodiversity?

Answer 2

Species richness

Question 3

What percentage of species on earth have been sampled, and what percentage of this are mammals?

Answer 3

15% sampled, 95 % mammals

Question 4

On what gradient does species richness increase?

Answer 4

Latitudinal gradient, increasing towards the poles

Question 5

Are the longitudinal and latitudinal gradients applicable to all species?

Answer 5

The latitudinal is widely accepted, the longitudinal is NOT

Question 6

Define delta diversity

Answer 6

The change in species composition and abundance over wide geographical areas.

Question 7

What are the lattitudinal and longitudinal gradients measures of?

Answer 7

Latitudinal gradient: delta diversity

Longitudinal gradient: climate diversity

Question 8

Where does marine species richness peak?

Answer 8

Plu or minus 30 degrees o the equator

Question 9

What gradients do coastal and oceanic species follow?

Answer 9

Oceanic species follow a latitudinal gradient, coastal species follow a longitudinal one

Question 10

What are three three species that do not follow latitudinal gradients, and what are their alternative?

Answer 10

1. Sea birds
   Have northern distribution due to greater productivity in the northern hemisphere
2. Lichens
   Max diversity in dry and cold regions
3. Microbes
   Classed as cosmopolitan, so are found anywhere without geographical boundaries

Question 11

What organism has no geographical boundaries to distribution?

Answer 11

Microbes

Question 12

What are the five hypotheses for latitudinal gradients of species distribution?

Answer 12

1. Geographical area
2. Energy species richness
3. Heterogeneity hypothesis
4. Rapports rule
5. Evolutionary speed

Question 13

What are the two sub theories of the energy species richness hypothesis?

Answer 13

1. Productivity hypothesis

2. Ambient energy hypothesis

Question 14

Explain the geographical areas hypothesis

Answer 14

The greater land area at the tropics provides more habitats for species, meaning a greater number of individuals in each species can be maintained- which reduces the extinction risk.
Large areas also facilitate more speciation, which allows for the development of ore species.

Question 15

Explain the energy species richness hypothesis

Answer 15

The amount of energy available directly influences the amount of co-existing species within an environment. This is measured via actual and potential evapotranspiration

Question 16

how is energy species richness measured?

Answer 16

Actual and potential evapotranspiration

Question 17

Describe the productivity hypothesis (part of energy species richness)

Answer 17

More resources means a greater plant biomass is supported, leading to more support for higher food chain levels and overall greater diversity.

Question 18

What can greater resource availability lead to?

Answer 18

Paradox of enrichment, and competitive exclusion

Question 19

Explain the ambient energy hypothesis

Answer 19

This is dictated by temperature, with it being physiologically costly for organism to live at high latitudes (temperatures are outside their optimal range), resulting in there being lesser species at the low temperatures found at high latitudes

Question 20

Explain the heterogeneity hypothesis

Answer 20

The greater the heterogeneity (diversity) of habitats located at the tropic means that more species can exist in these difference niches, leading to greater species diversity

Question 21

Explain rapports rule

Answer 21

At low latitudes, organism have small niches and partitioning occurs, meaning more organism can exist within a given habitat. At high latitudes, organism have very large niches, meaning that less species will exist in order to avoid their niches overlapping

Question 22

Explain the evolutionary speed hypothesis

Answer 22

The species richness at the tropics is a result of:

• long evolutionary history allowing for more speciation to occur
• stable conditions leading to stable existence
• constantly warm temperatures