THE ORIGIN AND EVOLUTION OF LIFE

UNIT 8

1. The beginning of life

Francesco Redi, 1668

Theory of spontaneous generation

1. The beginning of life

Louis Pateur, 1859

Theory of spontaneous generation

1. The beginning of life

Oparin’s theory, 1922

Methane, ammonia, hydrogen and water vapour were the components of the primitive atmosphere

Electricity from storms, volcano eruptions and UV radiation provided energy to start chemical reactions

As a result, organic molecules were formed and fell with the rain to the primitive ocean Bigger organic molecules were

formed in the ocean and isolated form the water in a kind of spheres called coacervates that were the ancestor of cells

Oparin’s theory

1. The beginning of life Miller’s experiment

1. The beginning of life

Panspermia theory

Life came form extra terrestrial spores transported by meteorites

1. The beginning of life

Hydrothermal vents provided energyMuddy soils provided mineralsVesicles with organic molecules were formedSelf reproduction of vesicles started at a certain rateRNA was supposed to be the first nucleic acid

Current theory

2. Evolutionary theories

Carl von Linné S. XVIII

George Cuvier S. XVIII

CREATIONISMSpecies are staticFossils are due to catastrophes

2. Evolutionary theories

Lamarck

Animals develop structures and organs they need to adapt to the environmentThose characteristics are transmited to the offspring

LAMARCKISM

2. Evolutionary theories

Charles Darwin

Individuals in a population are differentOrganisms produce more offspring than neededThey struggle for existenceIndividuals with the most advantageous characteristics will surviveThose favourable variations will be transmited to the offspring

DARWINISM

3. Evidences of evolution

HOMOLOGOUS ORGANS

3. Evidences of evolution

ANALOGOUS ORGANS

VESTIGIAL ORGANS

3. Evidences of evolution

3. Evidences of evolution

FOSSILS

3. Evidences of evolution

EMBRYOS RESEMBLANCE

3. Evidences of evolution

BIOGEOGRAPHY

3. Evidences of evolution

MOLECULAR SIMILARITIES

3. Evidences of evolution

CONVERGENCE

4. Present-day theories

SYNTHETIC THEORY

Mutations

Theodosius Dobzhansky

4. Present-day theories

THE SELFISH GENE THEORY

Richard Dawkins

4. Present-day theories

ENDOSYMBIOTIC THEORY

Lynn Margulis

4. Present-day theories

PUNCTUATED EQUILIBRIUM THEORY

4. Present-day theories

NEUTRAL THEORY

Motoo Kimura

5. Speciation

5. Speciation

MICROEVOLUTION AND MACROEVOLUTION

6. The appearance of human beings

6. The appearance of human beings

6. The appearance of human beings

6. The appearance of human beings

6. The appearance of human beings

A. Africanus H. erectus h. sapiens