Biodiveristy

Question 1

Define biodiversity

Answer 1

totality of all genes, species and ecosystems in once location

Question 2

Why does biodiversity occur?

Answer 2

Natural variation in the genotype of organisms that affects their physical appearance (phenotype)

Question 3

What is the first part of evolution?

Answer 3

Genetic Drift - Random changes in the frequency of an allele or a species is artificially killed off which causes those genetics to not be passed on

Question 4

What is the second part of evolution?

Answer 4

Natural selection - survival of the fittest to certain environments or changes means that the genes they possess are passed on.

Question 5

What is the third part of evolution?

Answer 5

Speciation - When a population of a species slits in varying proportions that causes them to then go off and develop different phenotypes over time

Question 6

What is Allopatric Speciation?

Answer 6

When a species is separated by a physical barrier such as a mountain range or continental drift.

Question 7

What is Peripatric Speciation?

Answer 7

A smaller part of a species breaks away from the main population. Distinguished from Allopatric through size of sub-population and reasons.

Question 8

What is Parapatric Speciation?

Answer 8

An unequal environmental gradient such as soil PH level mean that different parts develop to the specific part of that environment.

Question 9

What is Sympatric Speciation?

Answer 9

Disruption of the selection process due to deforestation or planting of new tree species gives populations a choice which may be divided and so the species will then develop in different environments

Question 10

What is vicariance and how does it affect speciation?

Answer 10

Seperation due to a geographical barrier (usually applies to allopatric speciation)

Question 11

How does sea level change affect speciation?

Answer 11

Sea level change causes different species to develop over time in response to different environments.

Question 12

How does mountain building affect speciation?

Answer 12

The formation of Andes led to separation of species on either side of range leading to unique but similar species. Usually causes allopatric speciation

Question 13

What happened in the Archipelago islands

Answer 13

Initially one ancestor on this island colonised the surrounding islands which over time resided and evolved there independently leading to speciation of various “Galapagos Finches” on each island to the ecological niches. This is known as adaptive radiation. They now consist of such different genotypes that that they are reproductively isolated.

Question 14

What is species redundancy?

Answer 14

Idea adopted by Walker 1992 that some ecosystems contain species that if removed would not affect its functioning dynamics.

Question 15

What is the counter argument to Walker 1992?

Answer 15

It is important to have as many species as possible as in the event of a problem there is more insurance.

Question 16

What happened in the coral reefs of the Caribbean in regards to biodiversity?

Answer 16

Sea urchin came to dominate the ecosystem that went on to spread disease causing the reef to be overgrown with algae. It is therefore important to have competitors to the sea urchin not remove those ones that are regarded as redundant.

Question 17

Who found in 2001 and 2006 studies that biodiversity improved GPP of the environment?

Answer 17

Tillman

Question 18

How does latitude affect biodiversity?

Answer 18

Not in a set way. Generally biodiversity increases as you approach the equator, however, this is not always true for example, the Sahara is located at the equator and has hardly any life. Moreover, the number of breeding birds increases from Eurasia to Finland.

Question 19

What is adaptive radiation?

Answer 19

Evolutionary process whereby species evolve and diversify from a common ancestor that occupied a wide range of varying environments/habitats.

Question 20

What does it mean if an ecosystem is stable and resilient?

Answer 20

If it is stable then all variables will return to initial equilibrium position following a perturbation or shock that initially displaced them away from it. Resilience refers to the speed at which this takes place.

Question 21

What might be some perturbations to an ecosystem?

Answer 21

Drought, freezing, fire, insect pests and disease

Question 22

What was McArthur’s proposed relationship between stability and diversity?

Answer 22

Increased diversity increases the amount of species which can collectively respond to perturbations, minimising their impact.

Question 23

What is a counter argument to McArthur’s proposed relationship between stability and diversity?

Answer 23

A perturbation upon a system may have a sort of domino effect whereby one small perturbation transcends through trophic levels.

Question 24

What was Robert May’s proposed relationship between stability and diversity?

Answer 24

He found that increased diversity reduced stability. The example he gives is heather moorland in upland Britain compared to limestone grassland that is not very resilient. He also found that in temperate forests if 7% of highly concentrated insects were removed then 50% of remaining insects would become extinct (Montoya, 2007)

Question 25

What are some of the major threats to biodiversity form humans?

Answer 25

Grazing, farming and settlements; over-exploitation of natural resources; Introduction of competitors (intentionally & unintentionally); Deliberate pesticide eradication; disease.

Question 26

What are some of the areas most at threat from reduced biodiversity as a result of humans?

Answer 26

Tropical regions and islands (Madagascar, Mediterranean Californian biome)

Question 27

How many areas did Myers outline as areas that should be preservation priorities and how many of them are tropical forests and Mediterranean ecosystems?

Answer 27

18 (14 tropical forests, 4 Mediterranean ecosystem)