Evolution of Life

1809 – 1882

born in Shrewsbury in Western England

naturalist when he was 16 years old

enrolled at Cambridge University to

become clergy man

Reverend John Henslew

Captain Robert FitzRoy preparing the

survey ship HMS Beagle for a voyage

around the world.

CHARLES DARWIN

22 years old collected South American

plants and animals

Lyell’s Principle’s of Geology (rocks

containing the fossils must have been

raised there by a long series of similar

earthquakes

collected birds in the Galapagos

He hypothesized that the Galapagos

had been colonized by organisms that

had strayed from South America

CHARLES DARWIN

November 24, 1859 Charles Darwin

published On the Origin of Species by

means of Natural Selection

it is focused in biologists’ attention on

the great diversity of organisms

DARWIN INTRODUCES A

REVOLUTIONARY THEORY

1. evidence that many species of

organisms presently inhabiting Earth

are descendants of ancestral species

that were different from the modern

species.

2. He proposed a mechanism for this

evolutionary process, which he

termed natural selection.

TWO MAJOR POINTS OF

DARWIN

A change over time in the genetic

composition of a population

gradual appearance of all biological

diversity, from the earliest microbes to

the enormous variety organisms alive

today.

Evolutionary adaptation an

accumulation of inherited

characteristics that enhance

organisms’ ability to survive and

reproduce in a specific environment

EVOLUTION

struggle for existence and the

capacity of organism to

‘overreproduce

unequal ability of individuals to survive

and reproduce

can increase the adaptation of

organisms to their environment

NATURAL SELECTION AND

ADAPTATION

Artificial Selection humans have

modified other species over many

generations by selecting and breeding

individuals that possess desired traits

NATURAL SELECTION AND

ADAPTATION

Human Immunodeficiency Virus

its connection to natural selection is

that it is more on the process of editing

than a creative mechanism

A drug does not create resistant

pathogens, it selects for resistant

individuals that were already present in

the population

THE EVOLUTION OF DRUG-

RESISTANT HIV

Natural Selection depends on time and

place

it favors those characteristics in a

genetically variable population that

increase fitness in the current, local

environment

what is adaptive in one situation may

be useless or harmful to others

THE EVOLUTION OF DRUG-

RESISTANT HIV

Comparison of body structures

between species

represent variations on a structural

theme that was present in their

common ancestor

HOMOLOGOUS STRUCTURE