Environmental Change and its Effects 1 of 22 Boardworks Ltd 2011
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What happens when habitats change? 3 of 22 Boardworks Ltd 2011 Adaptive evolution ensures that individuals within a species have traits allowing them to survive and reproduce in their habitat. If the habitat changes, however, successful traits can become a disadvantage. Organisms might have to move in order to survive. Changes in the environment will therefore affect the distribution of organisms. Some organisms might adapt and evolve in order to survive in the new environment. If an organism cannot survive as it is, evolve or move, it might die out. If the last individual of a species dies, the species becomes extinct.
What could change in the environment? 4 of 22 Boardworks Ltd 2011
Non-living factors causing change 5 of 22 Boardworks Ltd 2011
Changes in food webs 6 of 22 Boardworks Ltd 2011
The Golden Toad 7 of 22 Boardworks Ltd 2011 The introduction of a new disease can also cause organisms to becomes extinct. The Golden Toad was once abundant in areas of Costa Rica. Between the 1960s and the 1980s, their numbers dramatically declined. The last living Golden Toad was seen in 1989 and the species is now classified as extinct. Their extinction is thought to be the result of an infectious disease caused by a fungus, which may have been carried to the area by imported African frogs.
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Countdown to extinction 9 of 22 Boardworks Ltd 2011 Over 1.5 million different species of organisms have been identified, but scientists think there are many millions still to be discovered. Many of these organisms are threatened with extinction due to changes in their environments. Extinction has always taken place, for example, the dinosaurs are thought to have become extinct due to a comet striking the Earth. Extinction in modern times is increasingly caused by human activity.
10 of 22 Boardworks Ltd 2011 Why does extinction happen? Extinction rates are the highest since the death of the dinosaurs. We would expect one species each year to naturally become extinct, but human activity means the rate is closer to one species per hour. How does human activity cause extinction? destruction of natural habitats competition for resources over-hunting climate change pollution.
What caused these extinctions? 11 of 22 Boardworks Ltd 2011
Wildlife trade 12 of 22 Boardworks Ltd 2011 In the 1990s, over $160 billion worth of meat, skins, furs and other products of wild animals were shipped around the world each year. Some types of wildlife trade are legal, but the killing of protected species is not. What harm does wildlife trade cause? Harm to wildlife killing wildlife can unbalance entire food chains and lead to the death of other species. Harm to humans overexploitation of a species can leave people with no food in countries where rural households depend on local wild plants and animals.
Human-animal conflict As well as reducing the available territory and food, habitat destruction can change animal behaviours, bringing them into conflict with humans. Predator animals such as tigers start to prey on domestic livestock, and even humans, as their wild prey dwindles. Protected species are sometimes killed in order to prevent them harming people or their livelihoods. Organizations such as the Worldwide Fund for Nature try to relocate groups of animals that get too close to humans and encourage people to better protect their livestock and crops. Are these good long-term solutions? 13 of 22 Boardworks Ltd 2011
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What is biodiversity? 15 of 22 Boardworks Ltd 2011 Biodiversity means the variety of life on Earth. This includes: the variety of different species how many different types of birds, animals, fungi, bacteria, etc. genetic variation within species inherited differences between members of the same species. High levels of biodiversity makes an ecosystem more able to cope with environmental changes.
Why is biodiversity important? 16 of 22 Boardworks Ltd 2011 Biodiversity is important in maintaining ecosystems and protecting them from the effects of environmental change. Complex food webs containing many species mean that each species relies on many other organisms for its food. This allows them to adapt if one of their food sources disappears. Genetic variation means that some individuals of a species may survive an environmental change because they have slightly different characteristics. Extinctions reduce biodiversity, leaving ecosystems weaker.
What is an endangered species? 17 of 22 Boardworks Ltd 2011 To keep ecosystems stable, it is important to maintain biodiversity. This is one of the principles of sustainability. When a species is at risk of extinction, it is endangered. Over 1,100 animal species and over 700 plant species are classed as endangered or threatened. Animals that are endangered or threatened include the: gorilla giant panda snow leopard California condor blue whale.
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Endangered animals in the UK 19 of 22 Boardworks Ltd 2011
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Glossary 21 of 22 Boardworks Ltd 2011
Multiple-choice quiz 22 of 22 Boardworks Ltd 2011