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Web-based CourseWeb-based Course

วิ�ชา ควิามหลากหลายทางช�วิภาพในประเทศไทย

(Biodiversity in Thailand)

วิ�ชา ควิามหลากหลายทางช�วิภาพในประเทศไทย

(Biodiversity in Thailand)

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สถาบั�นบั�ณฑิ�ตวิ�ทยาศาสตร และเทคโนโลย�ไทย (สบัวิท.)

Thailand Graduate Institute of Science and Technology (TGIST)

สถาบั�นบั�ณฑิ�ตวิ�ทยาศาสตร และเทคโนโลย�ไทย (สบัวิท.)

Thailand Graduate Institute of Science and Technology (TGIST)

www.learn.in.th

LearnOnline@learn.in.th

www.learn.in.th

LearnOnline@learn.in.th

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ส#าน�กงานพ�ฒนาวิ�ทยาศาสตร และเทคโนโลย�แห%งชาต� National Science and

Technology Development Agency

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Prof. Dr. Warren Y. BrockelmanMahidol UniversityBangkok, Thailand

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Biodiversity

• Genetics

• Evolution

• Ecology

• Taxonomy

• Environmental Sciences

• Molecular biology

• Biotechnology

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Causes of Extinction of Species

• Habitat destruction• Pollution• Over Hunting

Current Rate of over Extinction ~ 1000 times the Natural Rate

The majority of species will become extinct before we will able to study or use them

(Natural Rate ~1 per 1-10 million species /year)

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“Biodiversity” = all the systems of living things (DNA, genes, individuals, species,

communities, and ecosystems)

Saving as many species as possible

The improvement of our lives and our very survival (biotechnology, genetic engineering, ecosystem function, beauty, ...)

8Food diversity

9Hidden products

10 Speiciesdiversity

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Genes to ecosystems

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Within species diversity

• Genetic variation

• Races

• Subspecies (geographic variation)

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Genetic Variation:

• Each individual is genetically distinct

• Measured by detecting variation in enzymes or proteins (direct products of genes)

• Measured by analyzing for differences in nucleotide sequences

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Ecosystem Variability:

= the differences in structure, productivity and nutrient cycles in communities in different types of environment and climatic zones of the Earth

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Ecosystem function is vital to all living

things

Nitrogen cycle

Carbon cycle

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History of Life

3.7 billion years The first living things

3.6 billion years aquatic cyanobacteria

2.5 billion years planktonic plants (O2)

400 Mya fishes

300 Mya land plants, insects

amphibians, reptiles

150 Mya first birds, mammals

65 Mya mammal radiations

2 Mya primitive humans

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History of the Earth (continue)

245 Mya The regign of dinosaurs, until

their extinction caused by

collision of a large asteroid

65 Mya with Earth

But normal rate of extinction approximately 1 species per 1-10 million

per year

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Evolution over millions of years

• Changes in populations through time

• Speciation (branching) , due to

Species diversity

•Separation (geographic speciation)

•Reproductive isolation

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Species: distinct types of organisms with reproductively separate populations

Each species: has distinct scientific name (Genus and species name)

We are: Homo Sapiens

Number of species in an areas is

the most useful measure of biodiversity

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How many species are there on Earth ?

5 to over 15 million species But only 1.5 million species have been described so far

• insects = 2/3 of all species • vertebrates = 40,000 species • vascular plants = 270,000 species • invertebrates = ?• fungi and microorganisms = ?

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Charles Darwin Era (Natural Selection):

• Individual Variation

• Inheritance from parents to offspring

• Population growth and competition

• Survival of the fittest

Evolutionary Change

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Important genetic principles

•Particulate inheritance

•“Genes” come in pairs

•Dominance

•Independent assortment

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Quantitative inheritance

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By 2000: Genetics, Molecular Biology

• genes and chromosomes• mutation • recombination• gene frequencies and selection• DNA structure and replication• transcription (protein formation)• nucleotide sequence

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DNA codes

for protei

ns

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A continuing controversy :

Is evolution gradual or

sudden?

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Genetic analysis reveals phylogeny

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99% of all species that ever evolued

are now extinct

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The study of biodiversity above the species level

• Population study• Ecological communities• Interactions (Stability & Diversity of communities)

- herbivores and plants- predators and prey- trees and seed dispersers- pollinators and plants- fungi and roots

• Ecosystem function and diversity

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Communities consist of many interactions

Nutrients plants

herbivores predator

diseases decomposer

dispersal migration

genetic change

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The flow of energy through a

community

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Species diversity in a community• Local extinction

• Colonization of immigrants

Number of species on islands affected by:

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Causes of Extinction

• Fragmented forest

• Small species population sizes

Species at most risk of extinction

•Low rate of population increase

•Poor dispersal ability

•Low natural density

•Hunted for their valuable parts

•In vanishing habitats

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Causes of Species loss

• Tropical forest destruction

• Forest fragmentation

• Hunting

• Pollution

• Damming and Canalization of rivers

Half the species on Earth (by next few centuries)

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Why save species?:

Because • Direct use to humans• Maintain ecosystems for survival of humans

If we lose species

•cannot be recreated

•loss of potential values or uses:

food

chemicals

genes

natural beauty

ecosystem stability

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How to slow down the extinction of species

• Reduction of human population increase

• Conservation of natural ecosystems as

“ protected areas”

• Reduction of rural poverty

• Special breeding programs for critical species

• Reduction of pollution and disturbance of rivers

• Diversification of forestry and agriculture to reduce monocultures

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Why save biodiversity?

The answer is:

you tell us!

Why do you want to save it?

Some general reasons  

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Because it pays. Many people make a living harvesting plants and animals, and using wildlife also. While this may not apply to you, it is wrong to destroy animals and plants that others need to make their living from.

Because we are part of an ecosystem that sustains us, by providing services such as clean water and air, rainfall, fertile soil, and pest control. Destroying animals and plants will ultimately harm us.

We do not have a natural right to destroy anything in nature, any more than we have a right to kill other people.

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