Year 12 Biology

1. Year 12 Biology

2. Why conserve? • Reasons why organisms are under threat Human impact – • habitat destruction – clearing for farms, houses, mines • hunting • pollution • introduced species (competition & predation) • Reasons for conservation Aesthetic value of biodiversity Ethics – is it right to destroy biodiversity? Custodial – we should preserve biodiversity for future generations Utility – biodiversity may provide useful products (e.g. medicines) Ecosystem stability – biodiversity contributes to ecosystem services Recreation/ecotourism Scientific research Education Better ability to cope with environmental change/greater genetic diversity

3. Levels of threat

4. Role of organizations in conservation strategies

5. Biological control • How it works an organism is found that acts as a control agent – usually predator or disease • Examples • Cactoblastis moth eats prickly pear • Calicivirus/myxomatosis kills rabbits • Lady birds & wasps eat insect pests (eg aphids, mealy worm) • Dung beetle disposes of cattle dung so there is nowhere for blowflies to lay eggs • Irradiated (sterile) male fruit flies released to breed with females  no offspring • Benefits • Once in place no need for further human intervention – its self regulating • It reduces use of poisons • Knowledge needed for effective use The control agent must not be able to become a pest itself: It is specific & won’t harm anything else, it won’t introduce a disease, it dies out when the food source dies out & it won’t hybridize with native organisms

6. Captive breeding programs • How it works Animals are bred in captivity (zoos or parks), then may be released back into the wild, or into reserves or parks. This may involve artificial insemination, in vitro fertilisation and or hand rearing of offspring Plants may be produced by tissue culture, cuttings or seed. Seed banks may store seed to maintain genetic diversity • Examples Numbats, chuditch, western swamp tortoise are bred then released into managed reserves (fenced areas where baiting programs have removed introduced predators eg foxes & cats) Other species bred at the Perth zoo include orang utan, gibbon, rhino Plants – Wollemi pine (ancient remnant of pines found in the Blue mountains – propagated by tissue culture, Jarrah resistant to dieback being propagated by seed and tissue culture • Benefits Maintains existence & genetic diversity of species under threat in natural habitats • Knowledge needed for effective use Reproductive technology (eg AI, IVF, tissue culture) Life cycle & breeding habits of species involved (eg apes must be taught how to raise young by seeing mothers or sisters doing it) , Symbiotic associations (eg orchids have a mutualistic relationship with fungi, Australian Christmas trees are semi parasitic on wattles, callistemons or eucalypts)

7. Conservation of wilderness areas/national parks • How it works set aside areas which are not cleared & human access is managed –eg some areas closed to humans, others restricted access • Examples Kakadu, Ningaloo reef, Great barrier reef, John Forrest National Park • Benefits preserves habitats & threatened species • Knowledge needed for effective use Ecological importance of protected area – numbers & types of threatened species present Lifecycle &habits of protected species – area must be sufficient to provide enough space, nesting/breeding spots and food for the species to be conserved

8. Reafforestation • How it works planting of trees/shrubs & other plants • Examples Planting to reclaim areas affected by salt or erosion Replanting after mining Restoring native bushland along roads and paddocks to provide a bush corridor Replanting along drains and swamps to repair damage of human impact Replanting to absorb carbon dioxide • Benefits Provides habitat, food & shelter for native animals Helps repair damaged areas (eg salt affected, eroded areas) Bush corridors allow small animals to move in safety – allows a larger area for foraging & connects small isolated populations  increase genetic diversity Absorbs carbon dioxide & reduces pollution • Knowledge needed for effective use Species originally present – so replanting is as close to the original as possible Species that are salt tolerant Preferred food sources/habitat for animal species you’re trying to attract Propagation/germination techniques – eg many species need fire to germinate Symbiotic associations (eg orchids have a mutualistic relationship with fungi, sandal wood & Australian Christmas trees are semi parasitic on wattles, callistemons or eucalypts)

9. Management of fishing and hunting eg bag limits, size limits, licensing • How it works limits are set on the numbers and/or size of animals being fished/hunted. Animals may only be hunted at certain times of the year • Examples Abalone can only be collected for a very short period, and only a few per fisher Fish, crayfish & prawns have minimum legal sizes – undersize animals must be returned Female crayfish & prawns with roe (eggs) must be returned Commercial fishermen must be licensed – this allows control of how much is taken Certain areas are set aside as non-fishing/hunting areas – this protects breeding grounds • Benefits Limits numbers taken to that of the population present Protects breeding grounds, youngsters & breeding females • Knowledge needed for effective use Population numbers present Lifecycle & breeding information eg many fish species start male & become female as they age (get larger) – if all the larger fish are taken, there may not be enough females to breed from

10. Development of new strains of crops/food animals • How it works new strains of high yield or disease/pest resistant crops/food animals are bred or genetically engineered • Examples Higher yield hybrid cereals eg rice, wheat Cereals that tolerate lower rainfall or salinity eg wheat Disease resistant crops eg wheat that resists rust Pest resistance – either by breeding or by inserting DNA eg GM canola & cotton Pigs and chickens that grow faster, so take less time to reach marketable size • Benefits Farms produce more food, more quickly Farmers can use areas that are dry or saline to produce crops Farmers can use less pesticide • Knowledge needed for effective use Lifecycles, physiology & genetic techniques

11. Short answer 2004 a & b European settlement in Australia has had a range of harmful effects on the environment. Widespread clearing of land for agricultural purposes has had a serious impact. a) Name four environmentally harmful effects of widespread land clearing. Introduced species are another major problem that came with European settlement. Grasses and other weeds have escaped from farms to establish themselves in bushland. b) Briefly explain two different ways these non-native plants can harm natural ecosystems.

12. Short answer 2004 a & b European settlement in Australia has had a range of harmful effects on the environment. Widespread clearing of land for agricultural purposes has had a serious impact. a) Name four environmentally harmful effects of widespread land clearing. Increased/changed salinity Increased soil erosion/increased runoff Decreased soil fertility Loss of animal habitat Loss of biodiversity Easy access for introduced species Climate change Desertification Rising water table/waterlogging/increased flooding Named effect on a neighbouring ecosystem 1 mark each to maximum of 4 Introduced species are another major problem that came with European settlement. Grasses and other weeds have escaped from farms to establish themselves in bushland. b) Briefly explain two different ways these non-native plants can harm natural ecosystems. Out-compete native species, leading to loss of biodiversity Native animals die when their food plants are excluded May be a food source for introduced species Changes to fire behaviour, so fires may be more or less frequent May be toxic to some native species, hence decline in numbers An example will be accepted instead of an explanation. e.g., outcompete native species such as bridal creeper smothering native vegetation May introduce disease and transmit to native vegetation 2 marks/line, maximum 4

13. Short answer 2004 c (c) To combat introduced pests, scientists sometimes use a strategy called biological control. • Briefly explain what is meant by biological control. ii) List three precautions that must be taken to ensure biological control does not get out of control itself.

14. Short answer 2004 c (c) To combat introduced pests, scientists sometimes use a strategy called biological control. • Briefly explain what is meant by biological control. Introduction of a natural enemy (predator, parasite, disease) to control pest numbers • List three precautions that must be taken to ensure biological control does not get out of control itself. The control must be specific The control must not introduce a disease The control must not be able to become a pest itself The control dies out when the food source dies out The control will not hybridize with native organisms

15. Short answer 2004 d & e Another problem is caused by the fertilisers used in agriculture and gardens. In particular, phosphate fertiliser can kill native plants that require little phosphate and it also causes toxic algal blooms in waterways. Part of the problem is caused by the fact that roadside drains in urban areas drain into waterways, carrying with them anything that goes down the drains. • Name four actions that householders can take to help minimise nutrient pollution of roadside drain water. • List four reasons why it is important to conserve our native biodiversity.

16. Short answer 2004 d & e Another problem is caused by the fertilisers used in agriculture and gardens. In particular, phosphate fertiliser can kill native plants that require little phosphate and it also causes toxic algal blooms in waterways. Part of the problem is caused by the fact that roadside drains in urban areas drain into waterways, carrying with them anything that goes down the drains. • Name four actions that householders can take to help minimise nutrient pollution of roadside drain water. Use low-phosphate/slow release/organic fertilizer Don’t wash cars on driveways Don’t flush food scraps down drains Dispose of pet droppings correctly Minimize fertilizer use/Plant natives that minimize fertilizer use/smaller gardens Use low-phosphate detergents and household products Don’t overwater/use a wetting agent Don’t overfertilize Don’t fertilize in winter • List four reasons why it is important to conserve our native biodiversity. Aesthetic value of biodiversity Ethics – is it right to destroy biodiversity? Custodial – we should preserve biodiversity for future generations Utility – biodiversity may provide useful products (e.g. medicines) Ecosystem stability – biodiversity contributes to ecosystem services Recreation Ecotourism Scientific research Education Better ability to cope with environmental change/greater genetic diversity

17. Extended answer 2006 37d Conservation of biodiversity in our ecosystems is a very high priority for biologists and governments around the world. However, not all organisms enjoy the same level of protection. Poison baits for rats and mice are sold in every supermarket but the community is horrified when whales are killed. Use named examples to illustrate the biological factors that should be considered when deciding the level of protection that should be given to various species.

18. Extended answer 2006 37d Conservation of biodiversity in our ecosystems is a very high priority for biologists and governments around the world. However, not all organisms enjoy the same level of protection. Poison baits for rats and mice are sold in every supermarket but the community is horrified when whales are killed. Use named examples to illustrate the biological factors that should be considered when deciding the level of protection that should be given to various species. Up to 8 marks for individual points that have been explained/described • Aesthetics • Ethics/culture • Economics – cost of protection of species • Economics – benefit/importance to human economy of species (eg harvesting or tourism) • How common is the species? • How widespread is the species? • Is the species a pest or does it have known uses? • What is the chance that the species will go extinct? • If the species goes extinct, will it lead to the extinctions of other species/ecosystem instability? • What kind of protection is needed? • What is the recruitment rate/reproductive potential of the species? • What is our knowledge about the species? • Need to conserve genetic diversity/biodiversity Up to 2 additional marks for very well elaborated additional points, 1 mark for each point Examples, can be rats/whales – up to 4 marks Named example of species needing high protection • Reason for protecting species • Explanation of type of protection needed Named example of species not needing high protection • Reason for not protecting species/giving low protection • Explanation of type of actions permitted against species

19. Genetic problem • What is the pattern of inheritance? • Write the genotypes for each individual • Individuals II3 and II4 are expecting another child. What is the probability it will show this condition?

20. Genetic problem Dd dd dd Dd • What is the pattern of inheritance? Autosomal dominant • Write the genotypes for each individual • Individuals II3 and II4 are expecting another child. What is the probability it will show this condition? 75% Dd Dd dd dd dd dd dd dd dd D_ D_ D d D DD Dd d Dd dd