Supporting Evidence for Evolution

Evolution evidence does not make sense unless there is an awareness of differences between living organisms

process of organizing and classifying organisms into certain groups by their differences is called taxonomy

Taxonomy comes from a root Greek word meaning “order” or “arrangement”

Taxonomic Classification: biological classification

classification; placing of similar objects into similar groups

Biological classification organizes all living organisms Structure, DNA, cell type, complexity, etc.

History of Classification

developed by Swedish scientist Carolus Linnaeus in the 18th century

Designed to have a universal naming system

binomial nomenclature- organism's scientific name is comprised of a combination of two terms: genus and species scientific name for humans- Homo

sapiens

Reason for universal naming system

Name this animal

Common name: PUMA, MOUNTAIN LION, COUGAR

Scientific Name: Felis concolor

Classification

DOMAIN

•Domain is the most broad while species is the most specific

•Mnemonic: o dear king phillip came over for good soup

Classification

Structures, functions and genetics help support the theory of evolution

Convergent evolution vs Divergent evolution Homologous Structures Analogous Structures Vestigial Structures Embryology Genetic similarities Atavisms

*Other supporting evidence: fossil records, relative/absolute dating

Convergent evolution

Convergent evolution: unrelated pathways to different species develop similar traits.

Similar traits develop due to similar environmental pressures.

These traits can be called analogous traits

Analogous Traits

Different structures with the same function

Divergent evolution

opposite of convergent evolution related pathways can develop

different traits over time: Natural selection, sexual selection,

genetic barriers and mutation drive these changes.

enough small changes accumulate in closely related but isolated populations, speciation might occur

Homologous Traits

Same structure but different function

characteristics that derive from shared common ancestry

Vestigial Structures (vestigial organ)

Many organisms possess vestigial structures

no apparent function, however; they resemble structures their presumed ancestors had Structures were once important Through evolutionary change the structures

became useless

Vestigial structure examples Humans-possess a complete set of

muscles for wiggling their ears human appendix is believed to be vestigial;

it represents the terminal part of the cecum

Vestigial Structures

Boa constrictors have hip bones and rudimentary hind legs

Vestigial Structures

Manatees, a type of aquatic mammal, have fingernails on their fins (which evolved from legs)

Vestigial Structures

Baleen whale, which contains pelvic bones, as other mammal skeletons do, even though such bones serve no known function in the whale.

Do Now Questions1. Which organism has the closest relationship

to Panthera leo? How do you know?

a. Felis concolor

b. Panthera tigris

c. Equus caballus

d. Canis lupus

2. Which format for scientific name is correct?

a. danaus plexippus c. Danaus Plexippus

b. Danaus plexippus d. Danaus plexippus

Embryology

study of embryos formation, development, structure and function

An embryo is an organism in its early stages of development

Comparative Embryology Comparing stages of early development from very different

animals provides evidence for commonality

Genetic Similarities (molecular homology)

Technology has allowed us to examine the DNA and protein structures/patterns from any organism in existence

Comparing different species DNA can undercover similarities and differences How closely related are these organisms?

Genetic Similarities

protein: hemoglobin-

Who are humans closest relative using hemoglobin testing?

Human Beta Chain 0

Gorilla (greater ape) 1

Gibbon (lesser ape) 2

Rhesus monkey 8

Dog 15

Horse,cow 25

Mouse 27

Gray kangaroo 38

Chicken 45

Frog 67

Lamprey 125

Sea slug 127

Soybean (leghemoglobin) 124

How similar are we when comparing DNA?

Another human? ~99.9%

A chimpanzee? ~97-98%

A mouse? ~90%

A fruit fly? ~45%

Yeast? ~25%

Genetic Similarities

Genetic Similarities

Humans chromosomes vs. chimpanzees chromosomes

Chromosome #2 fused

Atavism reappearance of a trait or characteristics in an

organism that is typical of an ancestral form (appearing trait has been absent from modern organism for many generations)

usually due to mistake in reading DNAExpressing “junk DNA”

Atavism can be seen in many different organisms

Atavisms

Human Atavisms

Cladogram

A tree-like diagram which shows the evolutionary relationship between

organisms

Reading and constructing a cladogram

vertebrae legs hair Opposable thumbs

jellyfish

lamprey

salamander

cat

gorilla

X

X

X

XX X

X

X

XX

jellyfish

lamprey

salamander

cat gorilla

vertebrae

hair

legs

Opposable thumbs

What can a cladogram tell you?ti

me

Speciation event•Common ancestor•Closest relative•Distant relative

Punctuated equilibrium and gradualism

Do Now

Fill in the chart and create a cladogram.

jaws lungs Amio-ntic sac

hair thumbs bipedal

Lizard

Tiger

Human

Salamander

Lamprey

shark

gorilla

Who is classified as a primate?

an animal order (classification) including lemurs, tarsiers, monkeys, apes and human beings

Primate Cladogram

New fossil evidence!

•Oldest primate ancestor was

thought to be 60 mya

•New primate ancestor found-

absolute dating puts its age at around 85

mya

BBC news: http://news.bbc.co.uk/2/hi/science/nature/1935558.stm

Earliest primate found thus far (85 myo)

Closer look at an ape cladogram

See video**

Comparing humans to great apes…

Comparing humans to great apes

Primate Hand

Comparing humans to great apes

Genetic comparison:

Humans and chimpanzees are ~97% similar in their genetic

compositionLarge difference- # of

chromosomesSee video**

What happened after the speciation event where chimps

and humans diverged?

•Environmental conditions that lead to chimpanzees: tree-dwellers•Environmental conditions that lead to humans: ground-dwellers

The modern human was not always this way…

See video**

Modern human skull

Evolution of humans

Evolution of humans

Lucy (3.2mya) and Ardi (4.4mya)

*Oldest fossils all found in Africa*

The oldest fossils in the evolution of humans have only been found on the continent of Africa, no where else.

Species are arranged according to the earliest date of fossils found so far ( a couple of recent discoveries are not shown). The red lines end because fossils have not been found any older for that species. **Note the overlap of time for species**

•Who is the closest relative to humans?•Is that relative alive today?

Specialized Characteristics:

•Depth perception (distance of an object)

•Binocular vision (using both eyes together)

•Social complexity (groups, communication)

•Opposable thumbs, grasping fingers

•Cranial capacity (size of brain; humans have the

largest capacity)

•Bipedalism (walking on two feet; strictly a human trait)

Why is this picture incorrect?

Evolution and the world

Can evolution be observed today?

YES IT CAN! Some bacteria and viruses evolve at a very

fast pace.