WALLACE RESOURCE LIBRARYLecture 02 – Evolution and Biodiversity in

Madagascar

This is an ‘example’ of a lecture that is given to A level students as part of their academic lecture series whilst on their expedition.It has been produced for the exclusive use of the lecturer conducting the series and is solely intended for educational purposes.Most of the material comes from Operation Wallacea sources and any other material that has been used has been credited (as far as is possible) to the appropriate author wherever possible.

This lecture is only to be used for EDUCATIONAL purposes.

WALLACE RESOURCE LIBRARYLecture 02 – Evolution and Biodiversity in

Madagascar

Madagascar -An extraordinary Island

Lecture 2: Biodiversity, biogeography and evolution of wildlife in Madagascar

Summary

• Introduction• Madagascar’s biodiversity• The Biogeography of Madagascar• Evolution of wildlife on Madagascar

• 400km of the east coast of Africa – In the Indian Ocean with the Mozambique Channel separating the island from Africa.

• The island is just bigger than France - 581,540 sq km – 4th largest island in the world – nearly 1000 miles long (north to south).

• About 165 million years Madagascar (with India attached) broke away from Africa and drifted Southeastwards.

• India eventually broke away leaving Madagascar isolated with all its ‘stowaway’ animals.

• Humans arrived about 2000 years ago – present population is probably above 19 million.

Introduction

• Can we define ‘biodiversity?• What is a species?• How can we measure biodiversity?• Is biodiversity important?

Madagascar’s Biodiversity

Biodiversity: a definition? Any ideas?

‘ Biodiversity includes all the different plant, animal , fungus and microorganism species worldwide, the genes they contain, and the ecosystems of which they form a part.‘

‘ Biodiversity is NOT just about the number of different species. It is also represents the degree of nature’s variety. Biodiversity takes into account the number of individuals and in how many places they can be found.’

Biological Diversity

Biological diversity occurs at the level of:

• Genetic diversity within species• Species diversity within an ecosystem• Ecosystem diversity within a region

www.nhm.ac.uk

Biological Diversity

http://www.greenfacts.org/en/biodiversity/figtableboxes/1012-richness.htm

Different ecosystems

Genetic biodiversity in mosquitos

Biological Diversity

• Evolutionary Species (Cracraft 1983)• Based on evolutionary relationships

• Morphological Species (Wiley 1978)• Based on visible characteristics• Easy to measure, most useful in practice• Not most biologically relevant

• Biological Species (Mayr 1942)• Based on reproductive isolation• Testable – in theory • Are hybrids fertile?

A species is often defined as a group of organisms capable of interbreeding (naturally) and producing fertile offspring.

Field Study Council

What is a species and what is it based on?

A quick quiz – answer on a sheet of paper.

1. A scientist (Erwin 1982) counted the number of beetle species in one species of tree in Panama (1200) – he used this to estimate how many species there were in the world - how many species did he estimate?• 30 – 50 million

2. Another scientists (Raven 1983) said there are twice as many species in the tropics than in temperate regions – what was his estimate?• 3 million

3. In June 2001 two organisations (Species 2000 and Integrated Taxonomic Information System) decided to work out together to create the catalogue of life. By 2007 how many named species were in the catalogue?• 1 008 965 species (this is now 1,740,330 in 2010)

4. Many scientists say that this represents what % of the actual total number of species?• 10%

How many species are there?

5. The UK Biodiversity Action Plan has made a list of species for the world and UK – if they estimate above 3 490 700 for the world – how many do they estimate for the UK?• 123 568

6. Rank the following for the greatest number of species for each group – ( 1 is for highest number of species)

Protoctista Vertebrates Plants Fungi InvertebratesBacteria

7. We have ignored viruses? (should we? Is it worth it?) They suspect there are millions of different types – how many have been described so far?• 5,000+

• Bacteria 4000+• Vertebrates

33700+• Fungi

70000+• Protoctista

80000+• Plants

293000+• Invertebrates 1280000+

How many species are there?

8. The agreed estimates for the total number of species varies greatly – the IUCN Red data List (1996) suggests between 5 million and (upper figure) ???? Million. Many scientists believe the figure to be much much higher.• 10 million

9. Suggest a couple of reasons why the estimates differ so much? • Difficult to see and find, defining a species, difficult to identify,

based on estimates, how they are measured.10.Which country had the highest extinction rate for animal and plant

species (IUCN 2007)?• United States of America – 236 animals and 30 plants

What does this tell us about estimating biodiversity?

How many species are there?

How do you measure biodiversity?

• by measuring organisms in the field (such as the work carried out by Operation Wallacea).• by using formulae such as:

• Simpson index (A level) D=1 - [ Σ(n/N)2 ] (n = number of individuals of a species, N = total number of all species)

• Shannon-Wiener index H’=Σpiln(pi) (pi = proportion of the species)

These formulae help to ‘quantify’ biodiversity but there is NO one formulae that truly represents a figure for biodiversity.

Some useful terms:

Species richness is the number of species in a given area.Species evenness is a measure of the relative abundance of the different species making up

the richness of an area.

• Madagascar is a biodiversity HOTSPOT (Myers 1988) – an area that holds especially high numbers of endemic species.

• There are 34 world biodiversity hotspots but they only cover 2.3% of the Earth’s land surface.

• Madagascar and its neighboring island groups have an astounding total of eight plant families, four bird families, and five primate families that live nowhere else on Earth.

• Madagascar’s more than 50 lemur species are the island’s charismatic worldwide ambassadors for conservation, although, tragically, 15 more species have been driven to extinction since humans arrived.

• Over half of the world’s chameleon species are found on Madagascar.• The natural vegetation of this particular ‘hotspot island’ is very diverse.

NHM

Madagascar biodiversity facts

Taxonomic Group

Species Endemic Species

Percent Endemism

Plants 13,000 11,600 89.2

Mammals 155 144 92.9

Birds 310 181 58.4

Reptiles 384 367 95.6

Amphibians 230 229 99.6

Freshwater Fishes

164 97 59.1

How do you think this compares to India and the UK?

Madagascar - Species numbers and endemism

Taxonomic Group Species Endemic Species Percent Endemism

Plants 13,000 15,000 11,600 4950 89.2 33

Mammals 155 350 144 44 92.9 12.5

Birds 310 1224 181 55 58.4 0.04

Reptiles 384 408 367 187 95.6 45

Amphibians 230 197 229 110 99.6 56

Freshwater Fishes 164 2546 97 284 59.1 1.1

How do you think this compares to India and the UK? India in RED

UK – only has 1 endemic bird and 16 endemic freshwater fish !!!

Scottish Crossbill

Image - RSPB

Madagascar - Species numbers and endemism

As many as 90% of the species are endemic to Madagascar

Unique flora and fauna in Madagascar

Taken at the Durrell – Jersey 2011

Your thoughts!

Summary ideas from the 2010 International Year of Biodiversity.

Biogeography of Madagascar

http://www.cbd.int/ts32/ts32-chap-10.shtml

Madagascar has THREE broad ecosystem types –

1.Dry forests in the north2.Humid forests in the east3.Spiny forests in the south

Madagascar dry deciduous forests (AT0202)Madagascar lowland forests (AT0117)Madagascar subhumid forests (AT0118)Madagascar spiny thickets (AT1311)Madagascar succulent woodlands (AT1312)Madagascar mangroves (AT1404)

Operation Wallacea research sites:Mahamavo - dry deciduous forests (AT0202)Ifotaka - spiny thickets (AT1311)

WWF ecosystems of Madagascar

Evolution of wildlife in Madagascar

Why is the Wildlife of Madagascar so different?Working in groups of 3 or 4 - Match the 10 pairs of cards together (Evolution Challenge) – e.g. pair a definition/picture with a KEYWORD – then briefly discuss within your group how the wildlife of Madagascar might have evolved (the cards are clues!).

Evolution of wildlife in Madagascar

Endemic

Fossils

Darwin and Wallace

Native to or confined to a certain region.

Giant lemur (skull )- 2,000 – 26,000 years ago – 200kg. Gorilla sized.

Dates: Wallace - (1823 - 1913)Darwin - (1809 -1882)

Why is Madagascan wildlife so different?

Why is Madagascan wildlife so different?

Evolution An overall change of a population’s

gene pool over time through processes such as mutation and

natural selection.

Isolation by continental drift

Allopatric speciation

Speciation following geographical isolation of

subpopulations of the species.

Variation The variety of life on Earth at all its levels,

from genes to ecosystems. Gene Pool

All the genes in a particular population at

a particular time.

Fitness The success of an individual (or

allele or genotype in a population) in surviving and

reproducing.

Natural Selection A process that explains how organisms with traits and

characteristics that are beneficial to survive in their environment are passed down to future generations

while less adapted dwindle/shrink.

• Introduction• Madagascar’s biodiversity• The Biogeography of Madagascar• Evolution of wildlife on Madagascar

Summary