COMMUNITY, BIODIVERSITY,

EVOLUTION

Ecosystem is the top of life’s hierarchy

Ecosystem depends on the complex interactions between its community of organisms and environment

ECOSYSTEM LEVELEucalyptus forest

COMMUNITY LEVELAll organisms ineucalyptus forest

POPULATION LEVELGroup of flying foxes

ORGANISM LEVELFlying fox

ORGAN SYSTEM LEVELNervous system

ORGAN LEVELBrain

BrainSpinal cord

Nerve

TISSUE LEVELNervous tissue

CELLULAR LEVELNerve cell

MOLECULAR LEVELMolecule of DNA

Figure 1.1

Basic Concept of Community

1. Structure

2. Species Interactions

3. Succession

4. Sustainability

Community structure

Community structure

Physical appearance Species Diversity Species abundance Niche structure

BIODIVERSITY

Distribution of species Species InteractionMain component of Biodiversity

Biodiversity of the world

Preservation of biodiversity is important to

humans for aesthetic, ethical and practical

reasons

Biodiversity provides humans with food,

clothing, shelter, oxygen, soil fertility, etc.

Biodiversity is vital to human welfare

How biodiversity evolve?

Evolution

The Fossil Record Fossils

◦ Organism’s hard parts preserved Turned to rock

Replaced by minerals

Or preserved in amber

Fossil record◦ Fossils found, catalogued & analyzed

◦ Shows transitions

◦ Incomplete

Three key ideas◦ Older fossils more different

◦ Increasing complexity with time

◦ Most species have gone extinct

The ways to explain evolutionary process

◦ Scorpion in amber

– “Ice Man”

Figure 13.2E, F

The Biochemical Evidence

DNA

◦ Similarities in Chromosomes and genetic code.

◦ Similarities in essential Amino Acids, gene structure

and gene function

◦ Changes slowly

◦ Also compare amino acid sequences

Cytochrome C

Humans and chimps identical

Rattlesnake 86% overlap

Evidence from Anatomy:

Vestigial Organs

Vestigial organs

◦ Internal features

◦ No useful function

Example

◦ Appendix: humans

◦ Wings: penguins,

cassowaries, emu

◦ Hind limbs: whales, snakes,

legless lizards

◦ Similarities in embryo of

vertebrates

Whale

Snake

Penguin

Similarities in Vertebrate embryos

Chemical Evolution

Chemical evolution

◦Process of combining

rocks, water and gases

Miller-Urey

experiment

Formation of cell

◦Still unknown

Black Smokers Black Smokers

◦ Deep-ocean floor

◦ Vents of mineral rich hot water

◦ Diverse ecosystem

Most archaic bacteria

Hydrothermal zones

◦ Site of life’s origin?

Protected

Ideal chemical environment

Many animals thrive in the extreme environment around hydrothermal vents

– Tube worms were unknown to science until hydrothermal vents were explored

– They live on energy extracted from chemicals by bacteria

The Window of Opportunity

Chemical processes

◦ Occurred rapidly

Recent discoveries

◦ Schopf

Evidence of life 3.5 billion years ago

First Cell

◦ 4.0-3.5 billion years ago

The First Cell

First cell

◦ No competition

◦ Multiplied rapidly

◦ No reliable replication

◦ Adopt genetic material from death cells

create biodiversity

Special characteristics

◦ Four nucleic acids in DNA (??)

◦ 20 amino acids

The Story of Life

First cell◦ Natural selection mutations

Mutations◦ Most not beneficial

Environment◦ Impacts evolution

Eukaryotes Colonies Hard Shell

◦ Cambrian explosion

Natural selection terjadi dalam waktu panjang

Geological Time

Mass Extinctions and the

Rate of Evolution

Rate of extinction

◦ 10%-20% extinct in 5-6 million

years

Mass extinctions

◦ 30%-90% extinct

Mechanisms

◦ Asteroid

◦ Volcanism *)

◦ Continental Drift

Evolution

◦ Gradualism

◦ Punctuated equilibrium

Darwin & Wallace

Natural Selection

◦ Variation in populations

Some variation heritable

◦ More individuals born than will survive

◦ Organisms are adapted to abiotic (regional climate) and

biotic factors.

◦ The presence and success of a species in a particular

place depends upon its ability to adapt

Natural Selection and the Development

of Complex Life

The evolution of insecticide resistance is an

example of natural selection in action

Chromosome with gene

conferring resistance

to insecticide

Additional

applications of the

same insecticide will

be less effective, and

the frequency of

resistant insects in

the population

will grow

Survivor

Insecticide

application

Darwin also saw that when humans choose

organisms with specific characteristics as

breeding stock, they are performing the

role of the environment

– This is called artificial selection

– Example of artificial selection in vegetables derived from wild mustard and dog pedigree

Dogs varieties

The Evolution of Human Beings

One of the regional descendents of H. erectus

was the stocky and muscular Neanderthals

◦ They lived throughout Europe from about 200,000 to

40,000 years ago

When and where did modern humans

arise?

Figure 19.6

One possible model of the somewhat bushy path of human evolution. The letters correspond to the following species:

O-Homo sapiensN-Homo neanderthalensisM-Homo heidelbergensis & Homo rhodesiensisL-Homo erectusK-Homo ergaster, Homo antecessor & H. mauritanicusJ-Homo habilusI-Homo rudolfensisH-Australopithecus garhiG-Paranthropus boiseiF-Paranthropus robustusE-Paranthropus aethiopicusD-Australopithecus africanusC-Australopithecus afarensisB-Australopithecus anamensisA-Ardipithecus ramidus

Orrorin tugenensis, Sahelanthropus tchadensis, & Ardipithecus kaddaba 7

We share more than 97% of our genes with

chimpanzees

– They are our closest living relatives

• Our behavior also has some similarities

– Chimpanzees make and use simple tools

– They seem to have a sense of self

Primitive human species

– Humans exhibit extreme physical diversity

Modern human species

Species Interactions

Species interactions

There are five basic types of interactions between species:

1. interspecific competition

2. predation

3. parasitism

4. mutualism

5. commensalism

These interactions tend to regulate the populations of species and can help them survive in changes environmental conditions

The competitive exclusion principle

– Populations of two species cannot coexist in a community if their niches are nearly identical

Hightide

Chthamalus

Balanus

Lowtide

Ocean

Competition

Intraspesific: competition between

members of the same species for the

same resources

Fig. 5.7

Interspecific: competition between

members of two or more different

species for food, space, or any other

limited resources

Succession

Communities in transition (ecological succession)

Communities constantly change in

response to change environmental

conditions.

The gradual change in species composition

of given area is called ecological succession

There are two types of ecological

succession :

1. primary ecological succession

2. secondary ecological succession

Primary ecological

succession

Sustainability

Human attitudes and environmental

awareness are of utmost importance in the

search for solutions to the biodiversity

crisis

Sustainable development in an ultimate goal

Extra Slide

The excessive use of antibiotics is leading to the

evolution of antibiotic-resistant bacteria

◦ Example:

Mycobacterium

tuberculosis

The evolution of antibiotic resistance in

bacteria is a serious public health

concern