Human exploitation of the environment

Question 1

Biodiversity: How are human activities altering ecosystems upon which they and other species depend?

Answer 1

In the oceans, stocks of many fishes are being depleted by over-harvesting, and some of the most productive and diverse areas, such as coral reefs and estuaries are being severely stressed

Question 2

Why is there a biodiversity crisis and how can it lead to extinction?

Answer 2

• Species are increasingly deprived of the biotic and abiotic factors that they need.
• As a result, they reproduce less successfully and population numbers decrease, in some cases, this leads to extinction

Question 3

What is extinction and how does it underline the biodiversity crisis?

Answer 3

• Extinction is a natural process that has been taking place since life originated
• normal background radiation mans that each year, one species In a million becomes extinct
• Human activity alone has increased extinction rates between 1000 and 10000 times

Question 4

What is the main cause of species extinction?

Answer 4

Human activity

Question 5

What is the IUCN and what does it do?

Answer 5

The international union for conservation of nature makes assessments of plants and grades them according to their vulnerability to extinction

Question 6

The IUCN rates species depending on their numbers, rate of decline and distribution:

Answer 6

(EX) Extinct
(EW) Extinct in the wild

(CR) critically endangered
(EN) Endangered
(VU) Vulnerable

(NT) near threatened
(LC) Least concern

Question 7

List some reasons why species become extinct:

Answer 7

• Natural selection
• Non-contiguous populations
• Loss of habitat
• Deforestation
• Drainage of wetlands
• hedgerow loss
• farmers sowing crops in autumn instead of spring
• overhunting by humans
• completion from introduced species
• Pollution

Question 8

Species become extinct for many reasons: natural selection

Answer 8

• Natural selection occurs when individuals less suited to prevailing conditions reproduce less successfully
• Their numbers decrease, which may lead to their extinction
• Human activities are causing habitats to change faster than new mutations allow species to adapt, and so they are driven to extinction at a faster rate than before humans had such influence over their environment

Question 9

Species become extinct for many reasons:

Non-contiguous populations

Answer 9

• the total number of individuals In a species may suggest that numbers are sufficient to ensure the continuation of the species
• But if groups are isolated from each other they cannot interbreed and each group functions as a separate population
• There may be too little genetic diversity in each to ensure a healthy population, leading to their extinction

Question 10

Species become extinct for many reasons: Hedgerow loss

Answer 10

• hedgerows have separated fields for centuries
• They provide a habitat for insects, nesting sites for birds and reptiles, food for many species and varying light intensity and water availability for diverse plants
• hedges act as wildlife corridors enabling organisms to move from one area to another, helping to maintain biodiversity
• Their removal has destroyed large areas of this specialised habitat

Question 11

Species become extinct for many reasons: farmers sowing crops in the autumn instead of the spring

Answer 11

• farmers often sow crops in autumn rather than spring, which means that plants are an unsuitable height for the birds to build their nests

Question 12

Species become extinct for many reasons: overhunting

Answer 12

• trophy hunting
• traditional medical practices
• bush meat industry
• overfishing
• Agricultural exploitation

Question 13

Species become extinct for many reasons: Competition from introduced species

Answer 13

• outcompeting native species

- native species subject to predation

Question 14

Species become extinct for many reasons: Pollution

Answer 14

Oil:

• prevents oxygenation of surface water
• contaminates drinkable water
• animals that break through the surface are covered by a film of oil, birds subsequently as chilled to death because their feathers clump together and cannot provide insulation
• washed up on beaches and ingested by shore dwelling animals, which are poisoned by it

PCBs: Polychlorinated biphenyls
- They are ingested with food and they are neurotoxins, carcinogens and hormone disruptors

Question 15

Define conservation

Answer 15

The sensible management of the biosphere to maintain habitats and enhance biodiversity, while allowing human activity. It maintains genetic diversity, both in the wild and in captivity. conservation is addressed in various ways, at local, national and international levels

Question 16

Conservation strategies: SSIs and SACs

Answer 16

• protecting habitats protects the species that live there and communities act as living gene banks
• They have varying levels of legal protection and may be managed and monitored by wardens

Question 17

Conservation strategies: International co-operation restricting trade e.g. Ivory and whaling

Answer 17

• organised attempts to stop it from happening

Question 18

Conservation strategies: Gene banks

Answer 18

• endangered species are protected and entered into breeding programmes in specialised zoos and botanic gardens

Question 19

Conservation strategies: Sperm banks

Answer 19

• are used to store economically important animals and of threatened species
• Rather than moving animals, sperm samples can be sent around the world to use in breeding programmes in other zoos

Question 20

Conservation strategies: seed banks

Answer 20

• maintain stocks of seeds of traditional varieties and of vulnerable species, in highly controlled conditions, often liquid nitrogen
• seeds degrade over time so samples are thawed and germinated, plants grown from them reproduce and another generation of seeds is collected

Question 21

Conservation strategies: Rare breed societies

Answer 21

• maintain older, less commercial varieties for special characteristics, e.g. Hardiness, wool production

Question 22

Conservation strategies: species reintroduction

Answer 22

Following successful breeding programmes, they are reintroduced to their former habitats

Question 23

Conservation strategies: Education

Answer 23

• world wide fund for nature: mount public awareness campaigns
• in the UK, the countryside commission, a government body promoting nature conservation, advises government and groups whose activities affect wildlife and their habitats. It produces publications, proposes ecosystems management schemes and establishes nature reserves

Question 24

Conservation strategies: legislation

Answer 24

• the EU habitats directive has imposed a range of measures to protect habitats and enhance biodiversity throughout Europe, preventing overgrazing, overfishing, hunting of game, collection of birds eggs, picking of wild flowers and plant collecting