I. BiogeographyA. Comparative Anatomy

1. “homologous” structures, similar2. Fossil record – similar structures, carbon dating

– evolutionII. Theories of Evolution

A. Catastrophism – large environmental disaster things change

B. Lamarck’s1. Inheritance of acquired – characteristics

(organism changed in it’s lifetime – could pass those changes to offspring)

C. Wallace – “survival of the fittest” evolutionD. Darwin – father of evolution 1858

1. Biological diversity – gene pool – there is always diversity within a species

2. Fitness – traits best suited for survival3. Natural selection – survival of the fittest, best

traits will be passed on4. Artificial selection – man selected, domestication5. Adaptation – allows for survival

a) Structural – anatomyb) Behavioral – courtship, hibernationc) Physiological – how the body works

III. Evidence for evolutionA. Radiometric dating – carbon 14 dating,

radioactive substances break down in half lives – decay

B. Fossils – imprints of structures within rockC. Comparative morphology and embryology –

development prior to birth1. Homologous features – similar structures,

similar embryological development, Ex. bat and bird wings2. Analogous features – similar functions develop

differently Ex. bat wings and butterfly wings3. Vestigial structures: present, no longer needed

D. Experimental evidence –• peppered moths, 2 variations white and gray• Trees with birch (lighter bark) And lichen – more white moths• 1860’s coal soot killed lichen trees

darken more gray moths• 1900’s less soot lichen back lighter bark-

more white moths

I. Change in frequency of alleles – how genetic information changes, which traits show up more often

II. Five agents in microevolutionA. Mutation – change in genetic code, lethal, neutral,

beneficialB. Gene flow – beneficial traits will be passed from

generation to generation – one population to another

C. Genetic drift – chance alteration of genes1. Founder effect – species in new environment will

favor certain genes2. Bottleneck – cheetah – severe reduction in

population small population limited gene pool, greater chance for genetic disorders

3. Inbreeding – homozygous limited gene pool, greater chance for genetic disorders

D. Nonrandom mating(sexual selection) – given member of a population is not equally likely to mate with any other given member “fittest”

E. Natural selection1. Adaptations – traits best suited for survival are passed

on2. Fitness – best adaptive traits3. Galapagos finches – Darwin – 13 finches – common

ancestor, beak size and shape – and Grant’s study – evolution can quickly occur

1. Three modesa) Stabilizing selection –

“average” most common

b) Directional selection – “change in the environment” shift to one extreme or the other

c) Disruptive selection – splits population into 2 groups

I. Species – interbreeding populations which produce viable offspring

II. Reproductive isolating mechanisms – keeps species separate

A. Prezygotic – prevents sperm from fertilizing egg

1. Mechanical – not physically compatible2. Behavioral – “behaviors” are different,

courtship song displays3. Temporal – breed at different times4. Gamete – egg and sperm cannot fuse5. Ecological – different habitats

B. Postzygotic1. Hybrids – offspring may not survive or be

sterile

III. Mechanisms of speciationA. Allopatric speciation – “of other countries”

1.species separated by geography change over time Darwin’s finches

a) Colonization – 1 group of finches 13 species new island, the fittest survive

b) Genetic divergence – over time species change due to adapting to new environment

c) Reproductive isolation – gene pool is separated from original gene pool – changes occur over time

d) Competition – fittest for environment survive to breed those characteristics to offspring

e) Further speciation – original species new species

B. Sympatric speciation – absence of geologic separation, fruit flies, hawthornes, apples

C. ????Parapatric speciation – next to small population on the fringe of a habitat can form it’s own breeding group

IV. Evolutionary change A. Vestigial structures: present, no longer needed

B. Coevolution – symbiotic relationships “mimicry”C. Comparative biochemistry – chemical makeup, horseshoe crab, blood chemistry same as spidersD. Genetics – DNA

V. Extinction: death of the last of a speciesA. Habitat destructionB. Competition

CHAPTER 18SYSTEMATICS:

SEEKING ORDER AMIDST DIVERSITY

I. Taxonomy A. Linnaeus – father of taxonomy, classification

system based on homologous structuresB. Binomial nomenclature

1. 2 term naming system2. Genus species – identification system Homo sapiens, Felis tigris, Felis leo

eastern bluebird (Sialia sialis), the western bluebird (Sialia mexicana), and the mountain bluebird (Sialia currucoides)—remain distinct because they do not interbreed.

C.Domains1. Archaea- ancient bacteria prokaryotes

2. Bacteria- modern bacteria prokaryotes3. Eukarya- eukaryotes divided into Animal, Plant,

Protist and Fungi Kingdoms

D. Kingdoms1. Animal – heterotrophs, multicellular, eukaryote2. Plant – autotrophs – multicellular, eukaryote3. Protist – heterotrophs & autotrophs, unicellular,

eukaryote

4. Fungi – heterotrophs, plant like, multi cellular, eukaryote

5. Monera – bacteria and viruses, prokaryotes

D. Taxonomic system Humans1. Kingdom Animalia2. Phylum Chordata “notochord”3. Class Mammalia “hair, mammary glands,

give birth to live young4. Order Primate “binocular vision,

opposable thumb”5. Family Hominidae “walk upright”6. Genus Homo “man-like”7. Species sapien modern day

E. Taxonomic Key – systematic way to identify organisms using structures

How Many Species Exist?

• Biodiversity is the total number of species in an ecosystem

Between 7,000 and 10,000 new species are identified annually, mostly in the tropicsTropical rain forests are believed to be home to two-thirds of the world’s existing species, most of which have yet to be namedBecause tropical rain forests are being destroyed so rapidly, species may become extinct before we ever knew they existed

The black-faced lion tamarinResearchers estimate that no more than 260 individuals remain in the wild; captive breeding may be the black-faced lion tamarin's only hope for survival

The (a) tarsier, (b) lemur, and (c) liontail macaque monkey all have relatively flat faces, with forward-looking eyes providing binocular vision. All also have color vision and grasping hands. These features, retained from the earliest primates, are shared by humans

Primates

• Some of these adaptations were inherited by humans– Large, forward-facing eyes with overlapping fields

of view (allowed accurate depth perception)– Color vision– Grasping hands– Enlarged brain (facilitated hand-eye coordination

and complex social interactions)

Oldest Hominid Fossils

• Hominids include humans and extinct humanlike primates

• The oldest known hominid fossils are between 6 and 7 million years old

Sahelanthropus tchadensis lived more than 6 million years ago

Exhibits human-like and ape-like characteristics

Oldest Hominid Fossils

• Ardipithecus ramidus and Orrorin tugenensis lived between 4 million and 6 million years ago

• Knowledge of these earliest hominids is limited - few specimens have been found

The first well-known hominid line, the australopithecines, arose about 4 million years ago

The Earliest Hominids

• The earliest australopithecines possessed knee joints that permitted bipedal (upright, two-legged) locomotion– 4 million year old fossilized footprints confirm that

early australopithecines sometimes walked upright

An upright stance was significant in the evolution of hominids because it freed their hands from use in walking

The Australopithecines

• Several species of Australopithecus have been identified from fossils

• Australopithecus anamensis• Australopithecus afarensis – believed to have

given rise to:– A. africanus– A. robustus – A. boisei

• All australopithecines were extinct by 1.2 million years ago

The Genus Homo

• The genus Homo diverged from the australopithecine line 2.5 million years ago

The Genus Homo

• Homo habilis appeared 2.5 million years ago– Bodies and brains were larger than

australopithicenes– Retained apelike long arms and short legs

Homo ergaster appeared 2 million years agoLimb proportions were more like those of modern humans

The Genus Homo

• Homo ergaster is believed by many to be the common ancestor of:–H. erectus (first hominid species to leave Africa

approximately 1.8 million years ago)–H. heidelbergensis• Some migrated to Europe and gave rise to H.

neanderthalensis• Those remaining in Africa gave rise to H.

sapiens (modern man)

Advances in Tool Technology

• Hominid evolution is closely tied to the development of tools

• Homo habilis produced fairly crude chopping tools that were unchipped on one end to hold in the hand

Advances in Tool Technology

• Homo ergaster produced finer tools that were typically sharp all the way around the stone– Some of these may have been tied to spears

Advances in Tool Technology

• Homo neanderthalensis produced exceptionally fine tools with extremely sharp edges made by flaking off tiny bits of stone

The Neanderthals

• Neanderthals lived in Europe from 150,000 to 30,000 years ago

• They were heavily muscled, had brains slightly larger than modern humans, walked fully erect, and constructed finely crafted stone tools

Neanderthals were once believed to be a variety of H. sapiens; however, molecular evidence indicates that Neanderthals are a separate species

Modern Humans

• Homo sapiens appeared in Africa about 160,000 years ago

• European and Middle Eastern H. sapiens appeared about 90,000 years ago and were known as Cro-Magnons

Cro-Magnons

• Cro-Magnons had domed heads, smooth brows, and prominent chins

• 30,000-year-old Cro-Magnon artifacts include:– Bone flutes– Ivory sculptures– Evidence of elaborate burial ceremonies

Unlike their predecessors, Cro-Magnons created remarkable cave paintings that made use of sophisticated artistic techniques

Cro-Magnons and Neanderthals

• Cro-Magnons coexisted with Neanderthals in Europe and the Middle East for as many as 50,000 years

• It is not known why the Neanderthals became extinct

Two hypotheses have been proposed for the evolution of Homo sapiens

“African replacement” hypothesis“Multiregional origin” hypothesis

“African Replacement” Hypothesis

• Members of the genus Homo made repeated long-distance migrations out of Africa beginning 1.8 million years ago

• H. sapiens emerged from Africa about 150,000 years ago and spread across the Near East, Europe, and AsiaThe dispersing H. sapiens populations replaced all other hominids

“Multiregional Origin” Hypothesis

• H. erectus emerged from Africa 1.8 million years ago and spread across the Near East, Europe, and Asia

• Continued migrations and interbreeding occurred among widespread H. erectus populations

• Regional populations of H. erectus evolved into H. sapiens

Large Brains

• Highly developed brains may have evolved in response to increasingly complex social interactions, such as the cooperative hunting of large game

If the distribution of this group-hunted meat was best accomplished by individuals with large brains, then natural selection may have favored such individuals

Characteristics made possible by a large brainLanguageAbstract thoughtAdvanced culture

The Cultural Evolution of Humans

• The evolutionary success of humans is the result of cultural evolution and a series of technological revolutions– The development of tools– The agricultural revolution– The industrial revolution

“We may not be suited for our role as stewards of life’s continuity on Earth, but here we are.”

Stephen Jay Gould