Linnaeus put organisms into groups based on physical characteristics.

The Linnaean system of classification has 7 levels:

KINGDOMPHYLUMCLASSORDERFAMILY GENUSSPECIES

Levels get increasingly specific from kingdom to species.

• The “Tree of life” summarizes the evolutionary history of all life on Earth in one simple graphic organizer• A wide variety of living organisms have inhabited Earth over millions of

years

• Many species went extinct at different points in Earth’s history

• 97% of all things have died out

• Rate is not uniform

• Modern living organisms would be “green leaves” on the tree

Kingdom--------

Phylum---------

Subphylum------

Class-----------

Order-----------

Family----------

Genus----------

Species---------

Animalia

Chordata

Vertebrata

Mammalia

Primates

Hominidae

Homo

sapiens

Scientific Name for humans = Homo sapiens or Homo sapiens

• 2 word system of naming• Written in Latin because it’s not used

• Common names may differ in different regions• Example: puma, mountain lion, cougar: all the same animal

• Common names may be misleading• Example: Worms

• Ringworm is a fungus

• Meal worm is an insect larvae

• Scientific names allow for precision

Organisms adapted to their environments

through acquired traits

change in their life time Use & Disuse

organisms lost parts because they did not use them — like the missing eyes & digestive system of the tapeworm

Perfection with Use & Needthe constant use of an organ leads that organ to increase in size — like the muscles of a blacksmith or the large ears of a night-flying bat

transmit acquired characteristics to next generation

1809-1882

British naturalist

Proposed the idea of evolution by natural selection

Collected clear evidence to support his ideas

Warbler finch

Woodpecker finch

Small insectivoroustree finch

Largeinsectivorous

tree finch

Vegetariantree finch

Cactus finch

Sharp-beaked finch

Small groundfinch

Mediumground finch

Large groundfinch

Insect eaters

Bud eater

Seed eaters

Cactuseater

Studied and took samples of different birds◦ Found 14 different species of finch—but only 1 was

located on the mainland.

Differences in beaks

associated with eating different foods

adaptations to foods available on islands

Seedeaters

Flowereaters

Insecteaters

Finches with beak differences that allowed them to…

◦ successfully compete

◦ successfully feed

◦ successfully reproduce

pass successful traits onto their offspring

1. All individuals in a population have variations.

2. Some of these variations allow individuals to successfully compete.

3. Those that “win” at competition are able to eat to survive.

4. The individual is able to reproduce and pass their variations on to their offspring.

Darwin called this:

Voyage: 1831-1836November 24, 1859, Darwin published

“On the Origin of Species by Means of Natural Selection”

A variation is considered an Adaptation when the trait enhances an organism’s ability to survive in a particular environment.

•Increases the fitness to the environment

•Increases the chance for reproduction/ survival and passing on its genes•Product of evolution by natural selection

•Example: size of moose’s antlers, coloring of a mouse

As more organisms survive with this variation, it will become more common in the gene pool.

This can lead to the development of new species!

A species can be defined as: a group of organisms that are able to interbreed and produce fertile offspring.

1. Behavioral- involves response to an organism’s environment

• Examples: birds migrate, bears hibernate, salmon swimming to spawning ground

**Remember, if it increases the survival of the organisms, then they can pass that trait on!!

• 2. Physiological: involves the function of a trait

• Example: poison of snakes,

• ink of octopus, etc.

3. Structural: involves the anatomy of an organism

• Example: bird’s beak

• horse's hoof

• anteater snout, ect.

• A method of hiding from predators by making oneself appear part of the natural surroundings

• When an organism imitates another organism for survival• Smaller, weaker animals have to imitate stronger

animals to stay alive.

• Insects or other less powerful animals can trick their predators into thinking they are a different animal by:• the sounds they make

• the colors on their body

•Examples:•Viceroy butterfly is a mimic of the monarch because the monarch is bitter to eat•Caterpillar mimics the look of a snake•Fly that mimics the look of a bee•Scarlet king snake mimics the coral snake (venomous)

Insecticide & drug resistance◦ insecticide didn’t

kill all individuals

◦ resistant survivors

reproduce

◦ resistance is inherited

◦ insecticide becomes

less & less effective

Other EXAMPLES?

LaMarck◦ in reaching higher

vegetation giraffes stretch their necks & transmits the acquired longer neck to offspring

Darwin◦ longer-necked giraffes survive

better & leave more offspring who inherit their long necks

VARIATIONS IN THE GENES!!

Are the living organisms we observe today the same as they were millions of years ago?

• Many species appear to have changed to various degrees over time giving rise to the modern forms of life we observe today

• All living organisms trace their history back

to various common ancestor “branches”

which ultimately traces back to a single common ancestor “tree trunk”

• humans and chimpanzees shared a common primate ancestor in the past ???

Fossil record◦ transition species

Anatomical record◦ homologous & vestigial structures

◦ embryology & development

Molecular record◦ protein & DNA sequence

Artificial selection◦ human-caused evolution

Layers of sedimentary rock contain fossils

◦ new layers cover older ones, creating a record over time

◦ fossils within layers show that a succession of organisms have populated Earth throughout a long period of time

Life’s Natural History is a record of Successions & Extinctions

Quaternary

Tertiary

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

Ediacaran

Precambrian,

Proterozoic,

&

Archarozoic

An

aero

bic

Bacte

ria

Insects

Rep

tile

s

Din

osaurs

Mam

mals

Bir

ds

Land P

lants

Seed P

lants

Pla

nts

Art

hro

pods

Ch

ord

ate

s

Jaw

less F

ish

Tele

ost

Fis

h

Am

phib

ians

Photo

synth

eti

c B

acte

ria

Gre

en A

lgae

Mult

icellula

r A

nim

als

Molluscs

1.5

4500

700

63

135

180

225

280

350

400

430

500

570

Flo

weri

ng

mya

Millions of years ago

50

100

150

200

250

300

350

400

450

500

550

60 55 50 45 40 35 30 25 20 15 10 5 0

Equus

HyracotheriumMesohippus

Merychippus

Nannippus

Body s

ize (kg)

Some species have evolved to be larger over time.

How does that work?

The horses that were born slightly larger were better able to escape predators andpass their “large bodysize” traits to their offspring.

Archaeopteryx◦ lived about 150 mya

◦ links reptiles & birds

• Links sea animals and land animals

New layers of rock cover older layers of rock

Scientists find fossils that exist in different layers

The fossils are linedup according to TIME

Similarities andDifferences are noted betweenfossils

*Ancestry is establishedor not established

1. Homologous Structures = similar shape, but different modern function◦ Similar forelimb bone structures for human, cats,

whales, & bats suggest they shared a common ancestor a long time ago

Modern animals may have structures that serve little or no function that were functional in ancestral species

◦ evidence of change over time

some snakes & whales show remains of the pelvis & leg bones of walking ancestors

eyes on blind cave fish

human tail bone

Why would whales have leg bones if they were always sea creatures?

Similar embryological development in closely related species◦ all vertebrate embryos have similar structures at

different stages of development

All of these creatures have gill pouches as embryos

This suggests a common ancestor that lived in the sea

3. Comparative Embryology

Comparing molecules of DNA and Proteins (sequences

of Amino Acids) can help biologists understand how closely related different species are.

◦ universal genetic code! DNA & RNA

◦ compare common genes

Closely related species have sequences that are more similar than distantly related species DNA & proteins are a molecular

record of evolutionary relationships

Number of amino acid differences betweenhemoglobin (146 aa) of vertebrate species and that of humans

100 20 30 40 50 6070 80 90100110120

LampreyFrogBirdDogMacaqueHuman

328 45 67 125

Figure 15.12A

Pleistocene

Pliocene

Mio

ce

ne

Oli

go

ce

ne

Brown bearPolarbear

Asiaticblack bear

Americanblack bear

Sunbear

Slothbear

Spectacledbear

Giant

pandaRaccoon

Lesser

panda

Ursidae

Procyonidae

Common ancestralcarnivorans

A Phylogenetic Tree recently revised based on comparative biochemistry suggests that the Giant Panda is more closely related to bears than raccoons

Artificial breeding can use variations in populations to create vastly different “breeds” & “varieties”

Lots of hidden variations come out!