18.3.217-18 · Selection, Evolution, Classification and Conservation
Reasons for Maintaining Biodiversity — Cambridge AS & A Level Biology 9700 Revision Notes & Topical Questions
5 min read 9 parts Lesson 31 of 36 1 quiz
Lesson summary
18.3.2 Reasons for Maintaining Biodiversity — CAMBRIDGE AS & A LEVEL BIOLOGY 9700 — REVISION NOTES notes: Explain the ecological, economic, aesthetic, social, ethical, environmental and agricultural reasons for maintaining biodiversity.Biodiversity — the range and variety of gene…
- Ecotourism
- Science and technology
- Moral and ethical
- Keystone species
- Ecosystem services
- Wild relatives
Part 1 of 8Biodiversity and the reasons for maintaining it
Biodiversity
- Biodiversity the range and variety of genes, species and habitats in a region.
- Componentsgenetic diversity, species diversity and ecosystem diversity.
Global biodiversity strongly affects humans and all other species.
Reasons for maintaining it:
- Ecological, economic, aesthetic, social, moral/ethical, environmental and agricultural.
Part 2 of 8Ecological reasons
Ecological reasons
Biodiversity affects the stability of an ecosystem.
- A diverse ecosystem is better able to survive and adapt to environmental change or threats.
- If a species-rich lake warms, some fish cope and keep contributing to the ecosystem.
Keystone species have a larger impact on the ecosystem than others.
- Bush elephants in the savannah knock over and eat trees, which maintains the ecosystem.
- Their dung is a habitat for fungi and insects.
- When ivory hunting reduced their numbers, the savannah suffered.
Part 3 of 8Economic reasons
Ecosystems have high economic value.
Medicines come from plants, fungi and bacteria, e.g. paclitaxel from Pacific and Himalayan yew trees.
- The Himalayan yew has declined because of overharvesting for fuel and medicine.
- Undiscovered drugs may still exist in nature.
Ecotourism
- Ecotourism income and jobs from tourists visiting national parks.
Science and technology
- Science and technology the enzyme used in DNA sequencing and PCR came from a thermophilic bacterium in a hot spring in Yellowstone.
Part 4 of 8Aesthetic, social and ethical reasons
Aesthetic
- Aesthetic people enjoy the beauty of nature, which inspires photographers, writers, musicians and artists.
Social
- Social people enjoy time in nature, e.g. birdwatching, walking and climbing, which may be lost if not conserved.
Moral and ethical
- Moral and ethical humans have a moral obligation to prevent biodiversity loss caused by their activities.
- Humans share the planet with millions of other species and have no right to cause their extinction.
- As the most intelligent species, humans carry the responsibility to protect them.
Part 5 of 8Environmental reasons
- Diverse ecosystems provide essential services.
- Plants absorb carbon dioxide, reducing the greenhouse effect.
- Microorganisms break down organic waste.
- Transpiration contributes to the water cycle, giving irrigation and drinking water.
- Fungi and bacteria recycle nutrients into the soil.
- Plants are producers in food webs and the direct or indirect source of food.
Part 6 of 8Agricultural reasons
Agricultural reasons
Most crops are uniform with low genetic diversity.
Wild relatives provide genetic diversity to rescue crops affected by disease or disaster.
- Many wild relatives are threatened by habitat destruction and climate change.
All the world's potato crop comes from one species (Solanum tuberosum), making it susceptible to disease.
- Over 100 wild potato species grow in the Andes and supply disease-resistance alleles.
- Alleles are introduced by gene technology and interbreeding.
Part 7 of 8Summary of the reasons
| Reason | Explanation |
|---|---|
| Moral and ethical | Humans have a responsibility to reduce their impact on the planet and other species |
| Ecological | Biodiversity increases ecosystem stability |
| Environmental | Organisms provide services such as the water cycle, nutrient cycle and carbon dioxide absorption |
| Economic | Medicine, ecotourism, science and technology |
| Aesthetic | Humans take pleasure from natural beauty |
| Agricultural | Diverse wild species can rescue crops from catastrophe |
Part 8 of 8More from the specification
More from the specification
Germplasm storage of plant seeds
- Germplasm storage of plant seeds cryopreserving wild plant seeds in ex situ gene banks protects agricultural biodiversity against extinction.
Ecological Reasons for Biodiversity Conservation
- Maintaining species and ecosystem diversity provides major life-support services including nutrient cycling, carbon sequestration, soil stabilization,
- and pollination of cultivated agricultural plants.
Assisted Reproduction in Endangered Animals
- Ex situ conservation programmes apply advanced reproductive techniques such as artificial insemination, in vitro fertilization (IVF),
- and embryo transfer into a surrogate female animal to boost endangered population sizes.
Invasive Alien Species and Ecological Competition
- The introduction of non-native invasive species poses severe threats to indigenous biodiversity through aggressive competition for limited food and nesting resources, predation,
- and transmission of novel pathogens.
Extinction Vulnerability in Small Populations
- Severely reduced populations suffer from inbreeding depression and loss of genetic diversity through random genetic drift, diminishing their evolutionary capacity to adapt to changing environments.
Native species
- A species that naturally lives in an ecosystem.
Marine park
- Protected area of water set up for marine conservation.
Conservation
- Protecting species and habitats.
Endangered
- At risk of extinction.
Population
- A group of organisms of one species in the same area at the same time.
Embryo
- A little ball of cells that forms from the first cell and develops into a baby.
Competition
- Two organisms needing the same limited resource.
Invasive species
- A species introduced to a habitat where it spreads and causes damage.
Endangered species
- A species at risk of extinction.
Captive breeding
- Breeding endangered species in zoos or reserves.
Key terms
| Term | Meaning |
|---|---|
| Biodiversity | Range and variety of genes, species and habitats in a region. |
| Keystone species | Species with a larger impact on its ecosystem than its numbers suggest. |
| Ecotourism | Tourism to see wildlife and natural areas. |
| Ecosystem services | Benefits provided by ecosystems, e.g. nutrient cycling and carbon dioxide absorption. |
| Wild relatives | Wild species related to crops that hold useful alleles. |
| Genetic diversity | Variety of alleles and genes within a species. |
Avoid these mistakes
1
Giving vague reasons such as "animals are important" — name the service, example and benefit.
2
Mixing up keystone species with the most abundant species — keystone species have a disproportionate effect.
3
Forgetting the agricultural argument — wild relatives provide alleles for disease resistance.
4
Treating economic benefits as only direct income — ecosystem services also have value.
Marked practiceQuizzes for this lesson
Last updated: