2. More on Biodiversity

Question 1

What is genetic diversity

Answer 1

The variation of alleles within a species (or within a population of a species).

Question 2

How to work out genetic diversity of a populations

Answer 2

Calculations can be used to monitor genetic diversity of population overtime & efforts can be made to increase it if needed.

Question 3

Eg of way to increase genetic diversity of a population

Answer 3

Breeding programmes in zoos are very closely managed to maximise genetic diversity.

Question 4

Why is it important to calculate the genetic diversity of a population

Answer 4

Important bc if a population has low genetic diversity, they might NOT be able to adapt to a change in the env & the whole population could be wiped out by a single event (eg. disease)

Question 5

Populations in which genetic diversity may be low

Answer 5

Isolated populations - sa those bred in captivity (eg. zoos, pedigree animals & rare breeds)

Question 6

What is a pedigree animal

Answer 6

One that has been bred purely from animals of same breed

Question 7

What is a rare breed

Answer 7

Usually a breed of farm anima that’s not used in large-scale farming

Question 8

What is used to measure genetic diversity

Answer 8

Genetic Polymorphism

Question 9

Using genetic polymorphism to measure genetic diversity

Answer 9

• Alleles are diff versions of a gene.
• Alleles of the same gene are found at the same point (called a LOCUS) on a chromosome.
• Polymorphism describes a locus that has 2 or more alleles.
• Working out the proportion of polymorphic gene loci in an organism gives you a measure of genetic diversity.

Question 10

Formula for genetic polymorphism

Answer 10

Proportion of polymorphic gene loci = no. of polymorphic gene loci / total no. of loci

Question 11

See pg112 for genetic polymorphism eg + %

Question 12

Factors affecting biodiversity

Answer 12

1. Human population growth
2. Increased use of monoculture in agriculture
3. Climate change

Question 13

Factors affecting biodiversity: 1. Human population growth

Answer 13

• Global population has increased hugely in recent centuries & continuing to rise, decreasing global biodiversity bc of:
  1. Habitat loss - human development destroys habitats (deforestation in Amazon for grazing & agriculture).
  2. Over-exploitation - greater demand for resources (food, water, energy) means theyre being used up faster than they can be replenished. (eg. industrial fishing can deplete populations of fish species, may even cause extinction). Decreasing genetic diversity within pop & species diversity (due to extinction).
  3. Urbanisation - sprawling cities/major road developments can isolate species, meaning pops are unable to interbreed & genetic diversity decreases.
  4. Pollution - high amounts of pollutants can kill species/destroy habitats (eg. fertiliser flowing into river –> decrease in fish species). Decreases biodiversity.

Question 14

Factors affecting biodiversity: 2. Increased use of monoculture in agriculture

Answer 14

• In order to feed an ever-growing no. of ppl, large areas of land are devoted to monoculture (eg. Africa, large areas used for palm oil plantations).
• Leads to decline in global biodiversity bc of:

1. HABITATS are lost as land cleared to make way for large fields, r educing habitat diversity.
2. Local & naturally occurring PLANTS & ANIMALS are seen as weeds & pests, so destroyed w pesticides/herbicides, reducing species diversity.
3. HERITAGE (traditional) varieties of crops are lost bc they dont make enough money & so are not planted anymore, reducing species diversity.

Question 15

What is monoculture

Answer 15

The growing of a single variety of a single crop

Question 16

Factors affecting biodiversity: 3. Climate change

Answer 16

1. Most species require particular climate to survive.
   - Change in climate may mean area that was previously inhabitable becomes uninhabitable (OR vice versa)
   - May cause increase/decrease in range of some species, increasing/decreasing biodiversity.
2. Some may be forced to migrate to more suitable areas, causing change in species distribution.
   - Migrations decrease biodiversity in areas species migrate FROM, & increase in areas they migrate TO.
   - If there isnt suitable habitat to migrate to, (species is a plant so cant migrate, or change is too fast), species may become extinct, decreasing biodiversity.

Question 17

What is climate change

Answer 17

• The variation in Earth’s climate, occurs naturally, but at moment being enhanced by humans increasing greenhouse gas emissions.
• Greenhouse gases (co2) cause global warming, causing other types of climate change eg. changing rainfall patterns.
• CC affects diff areas of world in diff ways - some get warmer/colder/wetter/drier.