Evolution

Evidence of change

The fossil

record

Similarities in body

structure

Similarities in early

development

Similarities in chemical

composition

Distribution of species

Paleontology Study of prehistoric life

Fossils

• preserved remains or traces of organisms;

• evidence of past life http://evolution.berkeley.edu/evolibrary/article/0_0_0/lines_03

http://www.nap.edu/openbook.php?record_id=6024&page=12

The Fossil Record Fossils and their placement in

rock formations and sedimentary

strata

Paleontology

How fossils

are formed

http://www.wwnorton.com/college/anthro/our-origins2/img/AskClarkFAQs/Figure-8.4.jpg

Paleontology

Geology • Estimate of

fossil’s age in

comparison

with other

fossils

• Layers may

not have been

deposited

horizontally or

may have

been

overturned

Radiochemistry

• Age of the

sample is

calculated

based on the

amount of

radioactive

elements

contained

• C14 N14

upon an

animal’s death

• C14>C12 =

older

organisms

• K40 for older

samples

http://evolution.berkeley.edu/evosite/li

nes/IIIAchronology.shtml

Paleontology

Fossils link the present with the past

• Baleonoptera musculus

(blue whale) • Modern marine mammal

• Basilosaurus • “king lizard”

• w/ 0.5m hind legs, w/ some

bones similar to those of land

mammals

• Ambulocetus natans • “walking whale that swims”

• Skeletons found in Pakistan

• Has a long, low body w/ short,

powerful limbs

• Descended from land-living

carnivorous hoofed animals

http://www.whale-info.com/bluewhale.html,

http://www.bbc.co.uk

Paleontology

Problems with the fossil record

1. Fossils form by chance

2. Quality of fossils varies

3. Fossil reconstruction requires thorough knowledge of anatomy

4. Dating of fossils is achieved through various methods

http://eweb.furman.edu

Paleontology

Comparative Embryology Similarities in early development

Closely-related

organisms have

similar stages in

embryonic

development

1. Tail

2. Pharyngeal

slits/pouches

/arches

http://www.nature.com/nrg/journal/v7/n11/fig_tab/nrg1918_F

2.html

Similar genes at

work

Similarities in early

development

Shared heritage from

a common ancestor!

Comparative Anatomy Similarities in body structures

http://hippie.nu/~unicorn/tut/img/basics/animalanatomy/wing-feathers.jpeg, http://www.uksafari.com/jpeg2/batwing2.jpg, ,

http://www.bugshop.com.au/images/Butterfly%20Wing.jpg

Similar structures

Homologous

Similar structure, different function

Due to common ancestry

Analogous

Similar appearance and function

Different origins

Similarities in body structures and

evolution

Divergent evolution or

adaptive radiation

• Common origin

• Descendants appear

different externally but

are similar internally

Convergent evolution

• Different origins

• Descendants

independently evolve

similarities when

adapting to similar

environments

Comparative Anatomy

http://itc.gsw.edu/faculty/bcarter/histgeol/paleo2/limbs.jpg

Comparative Anatomy

http://www.evolution-

textbook.org/content/free/figures/22_EVOW_Art/07_EV

OW_CH22.jpg, http://www.carolinabeachtoday.com

Comparative Anatomy

Vestigial structures • structures that are of marginal or little use to an organism

• e.g. coccyx and wisdom teeth in humans, hipbones and pelvis in whales, anal spurs in pythons and boas

• evolution is a remodelling process: ancestral structures may be modified as they take on new roles

http://3.bp.blogspot.com/-KAdBIaT796A/Ta-

KqBdscqI/AAAAAAAAABQ/KWFe8Ks8Oic/s1600/whale-

vestigial-structure.jpg, http://en.wikipedia.org/wiki/Anal_spur

Comparative Anatomy

Biochemistry and Molecular Biology Similarities in chemical compounds

Species pairs % difference in nucleotide sequences

& chimpanzee A 2.5

& gibbon B 5.1

& old world monkey C 9.0

& new world monkey D 15.8

& lemur E 42.0

A B C

D E

• Similarity of DNA b/w individuals of a species: related individuals > unrelated individuals

• Two spp. judged to be closely related by other criteria have a proportion of their DNA in common than more distantly related spp.

http://web.scc.losrios.edu/evanst/, http://andfinally.tv/2009/06/baby-gibbon-mothered-247-by-human/,

http://www.datensklaven.de/?tag=animals, http://eco-stride.blogspot.com/2007/10/monkey-mobilized-in-columbia.html,

http://www.naturalphotos.com/sekercioglu/madagascar/pages/MG8-TnZoo-RTLE.htm

,

***Hemoglobin: protein that transports O2 in blood

Central dogma of mol bio:

DNA RNA proteins

Structure of proteins dictated by DNA sequence Similar proteins ~ similar DNA sequence

***

Biochemistry and Molecular Biology

Similarity of chemical compounds

• sequences copied from a common ancestor

• common genetic code passed on along all the branches of evolution

Degree of relatedness

Biochemistry and Molecular Biology

Biogeography Distribution of species in space and through time

Gondwana broke up around 160 MYA eventually forming modern Antarctica, South America, Africa, Madagascar, Australia-New Guinea, and New Zealand, as well as Arabia and the Indian subcontinent

http://planet.uwc.ac.za/nisl/biodiversity/loe/images/pic231.gif

Modern

species

present on a

land mass

evolved from

ancestors that

inhabited

those regions.

• species are not

distributed only

according to

where they can

survive

http://evolution.berkeley.edu/evolibrary/article/history_16, http://faculty.scf.edu/odaffej/WasDarwinWrong.3/WasDarwinWrongEDIT6.html

Islands have many endemic species that are closely related to species of the nearest mainland or neighboring island. http://myweb.rollins.edu/jsiry/c1x17b-finches.jpg, http://www.galapagosisland.net/galapagos_islands/map.html

Islands have many endemic species that are closely related to species of the nearest mainland or neighboring island.

http://bonvito.files.wordpress.com/2010/11/carlito.png

Islands have many endemic species that are closely related to

species of the nearest mainland or neighboring island. http://people.eku.edu/ritchisong/birdbiogeography1.htm

http://people.eku.edu/ritchisong/wallacesline2.gif

Wallace Line - imaginary line separating ecozones of Asia and

Wallacea. West of the line are found organisms related to Asiatic

species; to the east, a mixture of species of Asian and Australian

origin is present.

http://people.eku.edu/ritchisong/554images/Zoogeographical_regions.jpg

http://worldpress.org/images/maps/world_600w.jpg