824208
Description
Flashcards by Sarah-Karolina V, updated more than 1 year ago
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Created by Sarah-Karolina V
over 10 years ago
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| Question | Answer |
| Biodiversity | the amount of biological or living diversity per unit area |
| species diversity | the variety of species per unit area. - this includes the number of species present and their relative abundance |
| habitat diversity | is the range of different habitats or number of ecological niches per unit area in an ecosystem or biome |
| what does conservation of habitat diversity lead to? | conservation of species and genetic diversity |
| genetic diversity | is the range of genetic material present in a gene pool or population of species |
| natural selection | charles darwin developed the theory of evolution by natural selection. this explained how the Earth's biodiversity has arisen |
| process of natural selection | * Speciation- when species are formed by gradual change over a long time * when populations of the same species become separated, they cannot interbreed and may start to diverge if the environments they inhabit change * separation may have geographical or reproductive causes; humans speed up speciation by artificial selection of plants and animals and by genetic engineering * over time the population gradually changes= natural selection * “the survival of the fittest” |
| isolation | the process by which two population become separated by geographical, behavioural, genetic or reproductive factors. |
| speciation | the process through which new species are formed |
| evolution | the cumulative, gradual change in the genetic characteristics of successive generations of a species. |
| geographical isolation | cause by a physical barrier that leads to populations becoming separated eventually leading to speciation. - cause can be ; plate activity, formation on moutons, seas, lakes, rivers and deserts |
| Physical Barriers (examples of species and speciation) - 3 | Large flightless birds (e.g. emu, ostrich, rhea, cassowary) only found in Africa, Australia, South America * cichlid fish in the lakes of East Africa, Lake Victoria, Lake Tanganyika, Lake Malawi * Llamas and camels (llamas in South America and camels in Africa and central Asia) |
| examples of Reproductive isolation | *behavioural isolation - courtship rituals * mechanical isolation - physical difference prevent mating |
| 3 types of plates activity | constructive, destructive, collision |
| 8 Factors that lead to loss of biodiversity | Natural hazards, loss of habitat, fragmentation of habitat, pollution, overexploitation, introducing non-native (exotic species), spread of disease, modern agricultural practices |
| What makes a species prone to extinction? | *narrow geographical range *small population size of reclining numbers *low population densities and large territories *few populations of the species a large body *low reproductive potential *specialized feeders or niche requirements *hunted for food or sport minimum viable population *size: that is needed for a species to survive in the wild is a figure that scientists and conservationists consider |
| example of a Recovered species | Australian saltwater crocodile § 18 out of 23 were once endangered § listed as protected species in Australia in 1971 § overexploited for skin (leather), meat and body parts through illegal hunting, poaching and smuggling § restored through ranching and closed-cycle farming |
| Example of an extinct species | o Thylacine (Tasmanian tiger) § life expectancy of 12-14 years § habitat: open forests and grassland § competed with dingoes on the mainland of Australia § hunted by farmers whose stock of sheep was the species’ prey § hunting, poisoning, and trapping § shooting parties organized for tourists’ entertainment § last one has been killed in 1930 § now introduced dogs have taken over the ecological role of the thylacine |
| example of an endangered species | o Rafflesia § tropical parasitic plant in the forests of South-East Asia § single sexed § pollination must be carried out when the plant in bloom § vulnerable because they need specific conditions to survive § deforestation and logging destroy their habitat § now there are Rafflesia sanctuaries |
| aims of the IUCN | * maintaining essential life support systems * preserving genetic biodiversity *Using species and ecosystems in a sustainable way |
| Buffer Zones | Contains habitats that are either managed or undisturbed |
| species based conservation | focuses on vulnerable species and raising their profile. |
| CITES | convention on the international trade in endangered - agreement aimed at preventing trade of endangered species |
| 3 advantages of CITES | - supported by many countries - it list many species - proved successful for many species |
| 3 disadvantages of CITES | - enforcement is difficult - fines are relatively small - support by some countries is limited and ineffectual |
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