Life processes in the Biosphere

Question 1

What is ecological succession?

Answer 1

movement to colonise new habitats

Question 2

What is the link between abiotically extreme environments and biodiversity?

Answer 2

Less abiotically extreme environments usually have higher biodiversity eg coral reefs

Question 3

How can the levels of biodiversity be measured?

Answer 3

Simpsons Diversity Index

Question 4

Simpsons Diversity Index

Answer 4

D= N(N-1)/Sum of n(n-1)
where:
N= Total number of organisms (all species)
n= Total number of organisms of an individual species

Question 5

What is an r-selected species?

Answer 5

species that can respond quickly to low survival rates. They reach sexual maturity quickly, produce many young and can disperse widely eg mice.

Question 6

What are K selected species?

Answer 6

Species that recover slowly from a decline in population. Reach sexual maturity at an older age, produce few young, but often live for a long time eg elephants

Question 7

What is Maximum Sustainable Yield (MSY)?

Answer 7

The MSY of a population is an estimate of the greatest exploitation that is possible without causing unsustainable long-term population decline

Question 8

What are density independent factors?

Answer 8

These include factors where the population density has no effect on the chances of survival of an individual eg drought, flood

Question 9

What are density dependent factors?

Answer 9

Factors where the chances of an individual surviving depend on the population density. eg food supply, disease

Question 10

What is carrying capacity?

Answer 10

the greatest population that an area can support indefinitely without damaging or over exploiting the environment- mortality rate can change so a population can return to its carrying capacity

Question 11

What is evolution?

Answer 11

the process that changes the gene pool of a species, driven by the increased chance of survival

Question 12

Define Biome

Answer 12

Area with a distinct climate and characteristic community

Question 13

Define ecosystem

Answer 13

biotic components and abiotic components all interacting together in a system and as a unit

Question 14

Define Habitat

Answer 14

the location where an organism/biological population lives, resides or exists

Question 15

Define community

Answer 15

A group of populations of two or more species occupying the same geographical area at the same time interacting with one another

Question 16

Define Population

Answer 16

A subset of individuals of one species that occupy a particular geographic area and interbreed

Question 17

Define species

Answer 17

A group of organisms that can freely interbreed to produce fertile offspring

Question 18

What is a niche?

Answer 18

How an organism fits into it’s environment, including it’s interactions with the physical environment and with other species it interacts with

Question 19

Describe how the loss of forest ecosystem services can impact humans (6 marks)

Answer 19

1) Loss of wildlife habitat meaning less food resources and loss of potential characteristics in agricultural species (for breeding programs).
2) Reduced root binding of soil meaning more soil erosion which means loss of land that supports agriculture
3) Reduced interception which could result in flooding of homes etc