David Attenborough's State of the Planet DVD Notes (Ep 2)

David Attenborough's State of the Planet DVD is recommended to watch in the Edexcel book for the Biodiversity Under Threat topic. This document is notes I made on Episode 2 of the DVD named "Why is there a crisis?". 

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  • Created on: 21-02-14 19:22
Preview of David Attenborough's State of the Planet DVD Notes (Ep 2)

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State of the Planet: Why is there a crisis?
Small islands suffer most of the effects of changes in the environment
Hawaii ­ most isolated group of islands on the planet
Tragically impoverished
More unique kinds of plants and animals than any other group of islands on earth
Emptied of biological riches
Hundreds of species animals and plants have disappeared since humans came to Hawaii
Humans arriving on different continents correlate with extinction rates
Big animals of Africa gives evidence of/cannot contradict the idea because they learnt to fear
humans over hundreds of years
John Lawton, expert in study of animal populations ­ identifies humans as a switching predators
Hedgehogs ­ example of a switching predator
5 hedgehogs taken from Scottish mainland to Uist to be garden pets
No predators to control numbers
Feed on anything (switching predators) so population rose from 5 to 10,000 in Uist
Dunlin birds' breeding success (and many other birds) are threatened by hedgehogs who eat their
In low tide sand bars connect Uist to other islands ­ hedgehogs can then walk from one island to
another and devastate other bird populations as they do so
Roadways also create links to other islands so hedgehogs don't always have to wait for low tides to
cross islands
5 factors (happening at an unprecedented speed) causing loss of species:

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More technology allows more harvesting to occur
Cutting down trees faster than they grow ­ regeneration of trees is not fast enough
Lack of trees affect species that depend on them
Trees cut down 10 times faster than they can grow back
Overharvesting in the sea ­ 70% of fish species are being removed at or above the rate at which they
can reproduce
Dr Silvia Earle, oceanographer ­ methods of fishing leads to overharvesting and take too much out
of the natural systems…read more

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Edward Wilson, Biologist ­ special study of the effect of human behaviour on the rest of life says that
human action was natural in order to survive but modern industrial capacity led to us succeeding too
Plant community with higher concentration of species than the Amazon Rainforest of South America
Biological hotspot
5,500 endemic plants grow there
The plants have small ranges so in some cases the whole world's population of a plant species fits
into the…read more

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Conducted by Tom Love Joy (conservation biologist)
Set up in the rainforest in Brazil
Regrowth of rainforests that were cut down still remain isolated because it often consists of only a
few weedy species
Islands of forest change from the centre to the edge ­ the nearer the margins, the more species will
have gone
Species are continuing to disappear even 20 years later because of changing conditions or because
the islands are not big enough to sustain their populations
Also occurs where forests are…read more

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Many mammals' fossils have been found proving that it used to be land ­ sea level rise
Shows that global warming can bring about changes in the distribution of animals and plants and any
future global warming is likely to do the same…read more


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