Evolution of Man

Evolution

Definition of Evolution the process by which species arise and

change over time. The idea that all organisms have

descended from common ancestors

Evolution

Charles Darwin Origin of Species, 1859 Decent with Modification Natural Selection Sexual selection

Evidence of Evolution

Fossil Record tells the story of evolution

Taxonomy Classifying organisms into groups

Comparative Anatomy Homologous structures Intermediate forms Vestigial structures

Comparative Embryology Early embryos of vertebrates are alike

Molecular Biology – DNA, proteins mtDNA

Fossils

An organism becomes a fossil only if it dies under the right conditions.

Majority of dead plants and animals are consumed by other organisms and leave no trace.

Dead organisms only leave a trace or imprint if they are quickly buried in a bog or at the bottom of a lake/ocean.

Clues of Human Evolution

Paleontologists find fossils

Clues of Human Evolution Remains of humans

were preserved in fossils

Bog is a wetland low in nutrients, slightly acidic soil .

Mossy Tollund Man. (Denmark) Europe Iron age 2,400

ya

Buried in mud or at the bottom of a body of water, the remains of the dead are protected from scavengers, erosion and decay.

Become buried deeply in successive layers of mud

Over time pressure from all these layers of sediment turns the deepest layers into sedimentary rock

After millions of years geologic forces raise the rock into mountains, canyons and reveal fossils

Sedimentary Rock

Grand Canyon showing layers of rock.

Taxonomy

All organisms are grouped into hierarchies based on their relationships.

Organisms of the same species can breed and produce viable offspring

Major taxonomic levels - KPCOFGS

Taxonomy

Common Name:

Human Chimpanzee Lion

Kingdom Animalia Animalia Animalia

Phylum Chordata Chordata Chordata

Class Mammalia Mammalia Mammalia

Order Primates Primates Carnivora

Family Hominidae Hominidae Felidae

Genus Homo Pan Panthera

Species sapiens troglodytes leo

Taxon0my

Binomial nomenclature Genus and species Homo sapiens. Homo means “self”

or “same”, meaning “the same as me” — which, for you, means “human”. Sapiens means “wise”. Homo sapiens means “Wise human”.

Comparative Anatomy

Species descended from a common ancestor may evolve in different directions and still keep some of the same characteristics

Evolutionary scientists compare the body structures of organisms to find clues.

Comparative Anatomy

Homologous Structures – similar structures in two or more species that give evidence of a common ancestor. Similar structure Same origin Different in function

Comparative Anatomy

Compare legs of Human and Ape

Comparative Anatomy

Intermediate forms – successive changes in homologous bone structures provide evidence of evolution.

Also called transitional forms

https://handfacts.wordpress.com/tag/evolution/

Comparative Anatomy

Comparing pelvis bones

Comparative Anatomy

Vestigial Structures A part of an

organism with little or no function that reflects evolutionary history

Comparative Embryology

Compare Embryo Development

Molecular Biology

DNA, mtDNA, proteins 20 -20,000 genes in the Human

Genome Molecular geneticists have compared

DNA sequences of Humans and chimpanzees

98.8% identical Humans are more closely related to

African apes than Asian apes (Immunological protein analysis)

Molecular Biology

DNA sequence comparisons

Mitochondrial DNA contains 37 genes Thirteen of these genes provide instructions

for making enzymes involved in oxidative phosphorylation. Oxidative phosphorylation is a process that uses oxygen and simple sugars to create adenosine triphosphate (ATP), the cell's main energy source.

The remaining genes provide instructions for making molecules called transfer RNA (tRNA) and ribosomal RNA (rRNA)

Mitochondrial DNA Passed from

mother to all her children

Points of mutations are a clear .

Molecular Biology

Observations

Primatologists observe our closest living relatives, apes and chimpanzees

Becoming Human

Sahelanthropus tchadensis Discovered in the Sahara Desert in 2001 Between 6 – 7 million years old Considered oldest known hominid fossil

Becoming Human

Homework

Look up Rift Valley Explain where it is Explain why it is important to the

study of Human Evolution.

Becoming Human

As we have evolved Humans have Larger brains Walk bipedally Sparse body hair Nonopposable toes and longer feet Grasping flexible thumb Unspecialized teeth Arching backs

Becoming Human

Australopithucus afarensis

Lucy Found in Ethiopia in 1974 This the earliest species

of Australopithecus, l ived in about 4 million

and 3 million years ago. brain was about the

same size as chimps 3 feet, 70 lbs

Becoming Human

The researchers also found that the model of locomotion produced in their simulations closely matched a set of fossilized footprints thought to have been left by A. afarensis in Laetoli, Tanzania, some 3.6 million years ago.

Becoming Human

They constructed the computer model using a fossilised A. afarensis skeleton known as "Lucy", recovered from Ethiopia in 1974. The researchers then added virtual muscle to their simulation and used genetic algorithms to "evolve" the optimal walking movement for the creature.

Becoming Human

Australopithicus africanus lived perhaps from 3

million to 1 million years ago, and probably evolved from A. afarensis

had a rounder skull and slightly larger brain

Tooth and jaw design suggest he chewed plant foods, but might also have scavenged meat from the remains of carnivores' kills.

Becoming Human

Neanderthal Man Fossils found in Germany

Becoming Human

Homo neanderthalensis More Neandertal skeletons

have been found than any other ancient human species. 

They lived in Europe and Southwest Asia from at least 130,000 -28,000 years ago.

May have evolved from Homo heidelbergensis in Southern Europe.

Becoming Human

protruding jaw, receding forehead, and

weak chin. The average Neanderthal

brain was slightly larger than that of modern humans, but this is probably correlated with larger body size in general.

May have been a different species than Homo sapiens.

Homo heidelbergensis (600,000 to 100,000 years ago)

The skulls of this species share features with modern Homo sapiens.

brain was smaller than most modern humans

Becoming Human

Homo sapiens sapiens Cro magnum man Earliest modern man Lived 35,000 ya The body heavy and

solid , muscular. Straight forehead with

slight browridges Cro-Magnons were the

first humans to have a prominent chin.

Neanderthal vs Cro-magnun

Comparison of erectus, aferensis, neanderthal

An evolutionary comparison (from left to right: Homo erectus, 1 million years old; Australopithecus afarensis, 2.5 million years old; Homo neanderthalensis, 100,000 – 32,000 years old)