3.1: biodiversity & conservation

Question 1

biodiversity definition:

Answer 1

biodiversity is a broad concept encompassing total diversity which includes diversity of species, habitat diversity and genetic diversity.

Question 2

species diversity definition:

Answer 2

in communities, it is a product of two variables, the number of species (richness) and their relative proportions (evenness)

Question 3

high/low species diversity in what habitats?

Answer 3

typically:
- high species diversity in habitats such as coral reefs and rainforests

• low species diversity in habitats such as urban habitats and polar regions

Question 4

how can communities be described and compared?

Answer 4

by the use of diversity indices.

when comparing similar communities, low diversity could be evidence of pollution, eutrophication or recent colonisation of a site.

no. of species present in an era is often indicative of general patterns of biodiversity.

necessary to repeat investigations of diversity in the same community over a period of time and to know if change is a natural process due to succession or if its due to impact from human activity. this could either increase or decrease biodiversity which in turn could tell us if conservation efforts are succeeding or not.

Question 5

habitat diversity definition:

Answer 5

refers to the range of different habitats per unit area in an ecosystem or biome.

Question 6

high/low habitat diversity in?

Answer 6

• high habitat diversity: in tropic rainforests as there are many ecological niches due to the layering of forests.
• low habitat diversity: in tundra

Question 7

advantages of a habitat w/ a high biodiversity -

Answer 7

 resilience and stability due to the range of plants present of which some will survive drought, floods, insect attack and disease.
 genetic diversity so resistance to diseases.
 some plants there will have deep roots so can cycle nutrients and bring them to the surface making them available for other plants.

Question 8

reasons why high biodiversity does not always equate to having a healthy ecosystem -

Answer 8

 diversity could be the result of fragmentation (break up) of a habitat or degradation when species richness is due to pioneer species invading bare areas quickly
 managing grazing can be difficult as plant species have different requirements and tolerance to grazing.
 some stable and healthy communities have few plant species so are an exception to the rule.

Question 9

genetic diversity definition:

Answer 9

refers to the range of genetic material present in a gene pool or population of species.

Question 10

high/low genetic diversity in what species?

Answer 10

• high genetic diversity: european red fox - found across Europe, humans – exist planet wide in many populations.
• low genetic diversity: grey seals – almost the entire world population of them are found on the Farne Islands off the north-east coast of England

Question 11

genetic modification

Answer 11

humans can alter genetic diversity by artificially breeding or genetically engineering populations with reduced variation in their genotypes or even identical genotypes – clones.

advantage -> if it produces a high-yielding crop or animal
disadvantage -> if disease strikes, whole population is susceptible.

this domestication and plant breeding has led to a loss of genetic variety, hence the importance of gene banks.

Question 12

advantage & disadvantage of genetic variation -

Answer 12

many conservationists would want to maximise genetic diversity by having many species and much variability within each species, so species have a better chance of adapting to change in their habitats.

but that could mean stopping succession as species diversity falls later in succession so interfering with the natural process.

Question 13

why is the quantification of biodiversity is important?

Answer 13

necessary for conservation efforts so that areas of high biodiversity may be identified, explored and appropriate conservation can be put in place where possible.

the ability to assess changes in biodiversity in a given community over time is important in assessing the impact of human activity in the community.

Question 14

biodiversity hotspot:

Answer 14

a region with a high level of biodiversity that is under threat from human activities.

there are hotspots where there are also unusually high numbers of endemic species (those only found in one place)

Question 15

facts ab hotspots -

Answer 15

• habitat contains more than 1500 species of plants which are endemic.
• they cover only 2.3% of land surface.
• tend to have large densities of human habitation nearby.
• they are threatened areas where 70% of the habitat has already been lost.
• tend to be nearer the tropics because there are fewer limiting factors in lower latitudes.
• they include about ten in tropical rainforest but also regions in most other biomes.

Question 16

critics of naming hotspots say they can be misleading because they:

Answer 16

• focus on vascular plants and ignore animals.
• do not represent total species diversity or richness.
• do not consider genetic diversity.
• do not consider the value of services, for example, water resources.

but they are a useful model to focus our attention on habitat destruction and threats to unique ecosystems and the species within them.