Conservation of biodiversity

Biology · A Unity and diversity. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.

Test this topic free All Biology topics

The idea

Biodiversity is the variety of life. It is measured at three levels: the variety of ecosystems, the number and evenness of species, and the genetic variation inside each species.

Fossils show that biodiversity recovered after each past mass extinction, and more species are probably alive today than at most earlier times. Species are now being lost much faster than the natural rate. The causes are human (anthropogenic), and the growth of the human population lies behind all of them.

No single method can save every species, so conservation uses several. In situ conservation protects species in their natural habitat; ex situ conservation keeps them somewhere else.

Rules to remember

Three levels of biodiversity: ecosystem, species and genetic.
Species diversity depends on richness (number of species) and evenness (how equal their numbers are).
Causes of the crisis: over-exploitation (hunting), habitat loss from land clearance and urbanization, pollution, invasive species and climate change.
Case studies: giant moas in New Zealand were hunted to extinction; dipterocarp forest in Southeast Asia is cleared for oil palm.
In situ: nature reserves, national parks, rewilding. Ex situ: zoos, botanic gardens, seed banks, frozen tissue banks.
EDGE = Evolutionarily Distinct and Globally Endangered: priority goes to threatened species with few close relatives.
Evidence for a crisis needs repeated surveys that use the same reliable method over a long time.

Common mistake

Students treat species richness as the same thing as biodiversity. A site where one species dominates is less diverse than a site with the same number of species in even numbers.

Worked example

A fungal disease is killing the last wild population of a frog, and the fungus cannot be removed from the habitat. Which conservation approach is needed first, and why is it not enough alone?

In situ protection of the habitat will not stop the deaths, because the fungus is still there.
Ex situ conservation (captive breeding of disease-free frogs) keeps the species alive.
Captive populations are small, so they lose genetic diversity and do not keep their natural behaviour and place in the ecosystem.
The habitat must also be protected so that frogs can be returned later.

Answer: Ex situ captive breeding first, combined with in situ protection of the habitat for later release.

Ask about this

Type what you are stuck on. The helper finds the explanation, worked examples and the notes to read, free and instant.

Read the full notes

A4.2 Conservation of Biodiversity

Keep going

← Evolution and speciation Carbohydrates and lipids →Take a Biology test