Biodiversity and its Conservation — Part 2: Loss and conservation of biodiversity: visual lesson, ISC Class 12 Biology

Lesson

Loss and conservation

Part 2 — why species are disappearing, and how they can be protected.

In this lesson you will

Name recent extinctions and explain the four major causes of biodiversity loss
Describe in-situ conservation: biosphere reserves, national parks, sanctuaries, sacred groves, hotspots, Ramsar sites and the Red Data Book
Describe ex-situ conservation, and the Earth Summit and World Summit

Concept

Loss of biodiversity

The IUCN Red List (2004) documents the extinction of 784 species (338 vertebrates, 359 invertebrates and 87 plants) in the last 500 years.

Table of recent extinctions
Recent extinction	Where
Dodo	Mauritius
Quagga	Africa
Thylacine	Australia
Steller’s sea cow	Russia
Three subspecies of tiger (Bali, Javan, Caspian)	Asia

Worked example

Worked example 1: reading the Red List

Of the 784 species documented as extinct in the last 500 years, 338 were vertebrates. What percentage is this? Which group contributed the most extinctions?

Vertebrates $= \dfrac{338}{784} \times 100 = 43.1$ percent.
Invertebrates (359) contributed the most, followed by vertebrates (338) and plants (87).

Worked table: 43.1 percent vertebrates
Group	Extinct species	Percent
Vertebrates	338	43.1
Invertebrates	359	45.8
Plants	87	11.1

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