Past Paper 2014 Flashcards
2 ways in which atmospheric carbon dioxide is important for life on Earth
Needed for photosynthesis
For the climate/temperature control
(Raw material for carbonaceous structures eg. Coral reef)
How sunlight is important for the survival of life on Earth
Provides energy for photosynthesis and photolysis
Can be converted to heat
Allows vision
Enables sense of time/ periodicity
Provides energy for hydrological cycle and biogeochemical cycle
Allows synthesis of vitamin D
Describe how early photosynthetic organisms changed the composition of the atmosphere
-reduced concentration of CO2 by absorbing it
- increased concentration of oxygen by releasing it
Oxygen enables formation of ozone
Explain how research into unexploited species may aid future food production
- new food species
- different range of tolerance
- source of new genes, new characteristics to improve existing food species
- biological pest control
- source of natural pesticides
Outline the features of a population which makes mark- release- recapture a suitable method for estimating population size
- individuals are mobile
- catching and marking does not affect adversely affect them
- the population size is not affected significantly by immigration or emigration
- the members of the population are mix freely, not terrritorial
- all members of the population are equally likely to be caught
- large enough population size/density for accurate estimates
Explained why having a small population makes a species vulnerable to extinction
- Individual deaths are greater proportion of population
- small gene pool
- problems of small gene pool, lack of genetic variability, more vulnerable to environmental change
- problems of inbreeding/ genetic disease/
- Few breeding individuals, hard to find a mate
- scarcity increases attraction to hunters
Suggest characteristics that released animal should have for a program to be successful. Released from captive and breeding or to a new habitat for a self sustaining population
- appropriate male and female ratio
- healthy/ disease free
- immune to local disease
- young, long reproductive life ahead
- genetically diverse population/not closely related
- survival skill (avoid predator, find food, avoid poisonous food, established territories)
Why carnivorous animals need larger protected areas than similar sized herbivorous animals
Less food for carnivores than herbivores per unit area
Energy lost in food chain
Live at Lower population densities = have large territories
Suggest how a river could be benefit
1 marginal changes ( remove hard bank/add soft bank, vegetation, nest sites, reduce bank slope, reduce turbid drainage, access for ducks)
2 flow rate/depth ( habitat diversity, vegetation diversity, breeding sites)
3 associated habitat ( planting reedbeds,
4 control of invasive, dominant, exotic species (competitor, predator, disease vector)
Explain how changes for biodiversity in a river may increase the amenity value of the river for visitors without damaging its wildlife value
- Aesthetics (habitat diversity, landscaping, indigenous species)
- Public activities ( walking, picnics, dogs on lead walking, fishing)
- Amenity features (foot paths, ca parks, information board)
- Removal of undesirable features ( litter, invasive species)
What is meant by ecological niche
The role an organism plays in its habitat. Giant pandas are niche specialists. They have a very limited diet, 99% bamboo. They have evolved specially adapted thumbs, which allow them to grip the bamboo, bamboo does not provide much nutrition so the pandas spend most of their time eating. Because the niche of pandas is so specialized, they are very vulnerable to human impact and their population have experienced dramatic declines
Grey reef shark become sexually mature at the age of 9 and then only give birth to 6 young every 2 years. Suggest why these facts make the species vulnerable to over exploitation
Females may be killed before they can produce
Reproduction rate lower than death rate
Give advantages of the no- fishing zone fo rythme population of the grey reef shark
Safe area to breed and to protect shark nursery
Protect sharks food
No habitat damage by fishing boat
Suggest reasons other than deliberate exploitation by humans why populations of some marine species, such as grey reef sharks are declining.
By catch
Impact of introduces species
Disease
Habitat destruction/ change (raising temperatures of water)
Explain the importance of coral reef to humans
Recreation, aesthetic, education, tourism Economic benefit to local community Food, fisheries Medicinal importance Biomimetics Coastal erosion, C02 absorption, carbon sequestration
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