COMMUNITY, COMMUNITY, BIODIVERSITY, BIODIVERSITY, EVOLUTIONEVOLUTION

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

Brain Spinal cord

Nerve

TISSUE LEVELNervous

tissue

CELLULAR LEVELNerve cell

MOLECULAR LEVELMolecule of DNA

Figure 1.1

Basic Concept of Basic Concept of Community Community 1. Structure2. Species Interactions3. Succession4. Sustainability

Community structureCommunity structure

Community structure

Physical appearanceSpecies Diversity Species abundance Niche structure

BIODIVERSITY

Distribution of species Species InteractionMain component of Biodiversity

Biodiversity of the worldBiodiversity 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 Biodiversity is vital to human welfarewelfare

How biodiversity evolve?How biodiversity evolve?

EvolutionEvolution

The Fossil RecordThe Fossil RecordFossils

◦ 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

The Biochemical EvidenceThe 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:Evidence from Anatomy:Vestigial OrgansVestigial 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 Similarities in Vertebrate embryosembryos

Chemical EvolutionChemical Evolution

Chemical evolution◦Process of combining rocks, water and gases

Miller-Urey experiment

Formation of cell◦Still unknown

Black SmokersBlack SmokersBlack Smokers

◦Deep-ocean floor◦Vents of mineral rich hot

water◦Diverse ecosystem

Most archaic bacteriaHydrothermal 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 The Window of OpportunityOpportunity

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 CellThe First Cell

First cell◦No competition◦Multiplied rapidly◦No reliable replication◦Adopt genetic material from death cells

create biodiversitySpecial characteristics

◦Four nucleic acids in DNA (??)◦20 amino acids

The Story of LifeThe Story of LifeFirst cell

◦ Natural selection mutations

Mutations◦ Most not beneficial

Environment◦ Impacts evolution

EukaryotesColoniesHard Shell

◦ Cambrian explosion

Natural selection terjadi dalam waktu panjang

Geological Geological TimeTime

Mass Extinctions and the Mass Extinctions and the Rate of EvolutionRate of Evolution

Rate of extinction◦ 10%-20% extinct in 5-6

million yearsMass extinctions

◦ 30%-90% extinct Mechanisms

◦ Asteroid◦ Volcanism *)◦ Continental Drift

Evolution ◦ Gradualism◦ Punctuated equilibrium

Darwin & WallaceNatural 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 Natural Selection and the Development of Complex LifeDevelopment of Complex Life

The evolution of insecticide resistance is an example of natural selection in action

Chromosome with geneconferring resistanceto insecticide

Additionalapplications of thesame insecticide willbe less effective, andthe frequency ofresistant insects inthe populationwill grow

Survivor

Insecticideapplication

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 BeingsThe Evolution of Human Beings

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 habilus I-Homo rudolfensis H-Australopithecus garhi G-Paranthropus boiseiF-Paranthropus robustusE-Paranthropus aethiopicusD-Australopithecus africanusC-Australopithecus afarensis B-Australopithecus anamensisA-Ardipithecus ramidus

Orrorin tugenensis, Sahelanthropus tchadensis, & Ardipithecus kaddaba 7

Primitive human speciesPrimitive human species

– Humans exhibit extreme physical diversity

Modern human speciesModern human species

Species InteractionsSpecies Interactions

Species interactionsSpecies interactions

There are five basic types of interactions between species:1. interspecific competition2. predation3. parasitism4. mutualism5. 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

Succession

Communities in transition (ecological Communities in transition (ecological succession) 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 succession2. secondary ecological succession

Primary Primary ecological ecological successionsuccession

SustainabilitySustainability

Human attitudes and environmental awareness are of utmost importance in the search for solutions to utmost importance in the search for solutions to the biodiversity crisis

Sustainable development in an Sustainable development in an ultimate goalultimate goal

Evolution and Modern Evolution and Modern Human LifeHuman Life(Extra Slide)(Extra Slide)

The excessive use of antibiotics is leading to the evolution of antibiotic-resistant bacteria◦Example:

Mycobacterium tuberculosis

The evolution of antibiotic The evolution of antibiotic resistance in bacteria is a resistance in bacteria is a serious public health concern serious public health concern

Pathogenic bacteria can cause disease by producing◦exotoxins, such as

Staphylococcus aureus

◦endotoxinsLyme disease is

caused by a bacterium carried by ticks

Some bacteria cause diseaseSome bacteria cause disease

These bacteria photosynthesize in a plant-like way◦They often “bloom” in polluted water

Cyanobacteria sometimes Cyanobacteria sometimes “bloom” in aquatic “bloom” in aquatic environmentsenvironments

The species that causes anthrax can be used as a biological weapon in war or in acts of terrorism

Many prokaryotes are environmentally important in Earth’s chemical cycles◦We exploit decomposers in sewage treatment

Prokaryotes help recycle chemicals and clean up the Prokaryotes help recycle chemicals and clean up the environmentenvironment

Rotatingspray arm

Rock bedcoating withaerobicbacteriaand fungi

Liquid wastes Outflow

Prokaryotes hold a great potential for solving environmental problems such as oil spills and toxic mine wastes