Practise conservation by tracing extinction pressures, weighing the value of biodiversity and outlining practical ways to preserve endangered species.
Measurements of the surface temperature of land and oceans can be taken from locations around the world. The mean global surface temperature for land and ocean combined can be calculated for a fixed time period.
Scientists calculated:
- the mean global temperature for the twentieth century
- the mean global temperature for each decade (ten years) from 1880 to 2020.
The mean temperature for each decade was compared to the mean for the twentieth century. For each decade, the difference in temperature was calculated.
The calculated differences are shown in Fig. 10.2.
Fig. 10.2
Moose populations have decreased in North America since 1980.
Suggest and explain reasons for the decrease in moose populations.
Over the past 200 years, many species of animals and plants have become extinct.
Fig. 8.1 shows the changes between the years 1800 and 2000 in:
- the number of species becoming extinct
- the size of the world human population.
number of known extinct species
world human population ( )
It has been suggested that there is a correlation between the number of species becoming extinct and the size of the world human population.
Suggest reasons for this possible correlation.
Extinction of animal and plant species reduces biodiversity.
Explain why it is important to maintain biodiversity.
Many zoos around the world are involved in captive breeding programmes for endangered species.
Outline the role of zoos in the conservation of endangered species, other than captive breeding programmes.
Chester Zoo, in the United Kingdom, controls the European captive breeding programme for the eastern black rhinoceros, Diceros bicornis michaeli.
Fig. 10.1 shows an eastern black rhinoceros.
Fig. 10.1
In the captive breeding programme for the eastern black rhinoceros, 15.8% of females breed each year while in the wild 23.7 % of females breed each year.
Suggest reasons why fewer females breed in captivity than in the wild.
Sometimes assisted reproduction is used in captive breeding programmes for the eastern black rhinoceros.
Fig. 10.2 outlines the process of IVF that is used in these programmes.
Fig. 10.2
Outline:
- the event A that occurs in the production of the embryos
- the two other possible outcomes, B and C, for the embryos that have been produced.
Extinction of animal and plant species reduces biodiversity.
Explain why it is important to maintain biodiversity.
Zoos work with local groups around the world to help conserve endangered species. One example of this is the use of assisted reproduction, such as IVF, with endangered mammals such as the eastern black rhino.
Outline the process of IVF.
The Asian common toad, Duttaphrynus melanostictus, arrived accidentally in eastern Madagascar in 2010 on a ship.
Fig. 9.1 shows an Asian common toad.
Fig. 9.1
The Asian common toad is now regarded as an invasive alien species because:
- it breeds fast in the warm, wet conditions of eastern Madagascar
- it can travel up to 2.5 km per year
- its skin contains poison, which is highly toxic to humans and predators.
Suggest ways in which the Asian common toad may affect the ecosystem of eastern Madagascar.
Bears are several species of mammal in the family Ursidae.
Climate change and loss of habitats due to human activity have reduced the size of some bear populations in recent years.
The International Union for Conservation of Nature (IUCN) has a role in the conservation of species, such as species of bear.
Outline the role of the IUCN in the conservation of species.