A4.2 Biodiversity (year 6)

Question 1

Has biodiversity changed over time?

Answer 1

• rate of extinction is very high
• no. of species alive today is lower than it was a 100 years ago
• evidence from fossils suggests the same thing
• however during periods when speciation is higher than extinction rate, there could have been more species alive today compared to any other time period

Question 2

2 case studies of anthropogenic species extinction

Answer 2

North Island giant moa;
- extremely large herbivorous birds with no wings
- females larger than males
- New zealand was populated by polynesian people around 1200-1300 CE, where it is estimated that the North Island giant moa was hunted to extinction within 100 years of human arrival on the island

Caribbean monk seal:
- declared extinct in 2008
- docile marine mammals living in and around the waters of the Gulf of Mexico and Caribbean islands.
- killed the seal for its oil to use in lamps and for food, showing little fear of approaching humans = easy to hunt down

Question 3

What is anthropogenic species extinction?

Answer 3

extinction of a species caused by human activity

Question 4

1 case study of ecosystem loss

Answer 4

Mixed Dipterocarp forests in SEA:
- dopterocarps are a family of hardwood, tropical trees comprising of about 500 species.
- Some regions of SEA have lost over 50% of their dipterocarp forested area where the forested land is completely stripped of its trees (clear-cutting) and there is a total loss of the local ecosystem.
- clear-cutting is the most economic option and is used to make the land available for agricultural use

Question 5

Evidence for a biodiversity crisis (prob not tested)

Answer 5

Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES);
- published a comprehensive report that provided significant and reliable scientific guidance for policymakers.

ICUN red list:
- continuously updated list of the worlds threatened species
- one of the most comprehensive and trusted sources of info with extinction status of over 140,000 fungus, plant, animal species.
- currently more than 40,000 species are listed as threated with extinction

Question 6

Causes of the biodiveristy crisis

Answer 6

• human population growth
• hunting, urbanization, deforestation, clearance of land for agriculture = loss of natural habitat
• pollution, spread of pests, diseases, alien invasive species due to global transport

Question 7

Examples of approaches to conserve biodiversity

Answer 7

In situ (managing natural areas):
- establishment of national parks = provide ecosystems from being lost as a result of extraction of resources
- rewilding of areas damaged by human intervention = allow species that were previously lost from an area to return to increase biodiversity
- reclamation of degraded landscapes = rebuild and replant as much of an ecosystem as possible

Ex situ (managing species outside their natural area):
- breeding programmes by zoo
- seed banks
- animal tissue banks

Question 8

describe the EDGE of exsistence programme

Answer 8

• a global programme with the goal of selecting evolutionarily distinct and globally endangered species
• aims to inform governments, conservation organizations and local populations of the eoclogical peril of different species.
• species that are the most endangered (by the IUCN red list) and the most evolutionarily distinct (using DNA sequencing info) are given a high EDGE score and are prioritised