e & e

E & EE & E

Some evidence for evolution

A. Direct Observation of Microevolution

• Adaptation and Speciation • Natural Selection (many examples, a few covered previously)

B. The Fossil Record - gives us much information• stratification of fossils

• dating of fossils, sediments

– radiometric dating

– fission track dating

– electron spin resonance dating

– thermoluminescence dating

Sedimentary Layers – The Grand Canyon

Fossil Crinoid Stems and Brachiopods

A Trilobite (Odontochile formosa) from Lower Devonian of the Kinglake district(Source: Museum Victoria.)

(Trilobites lived from the Cambrian – Permian; 545 – 251 mya)

Geologic Time Scale

Fission Track Dating of Uranium

• transitional/intermediate forms, vertebrate examples(see http://www.talkorigins.org/faqs/faq-transitional.html for in-depth treatment).• pageant of whale (e.g. transitional Ambulocetus), and horse evolution (Illustrated on the following slides.)• many hominid transitions (e.g. Australopithecus is transitional between Pan and Homo – we’ll study later)• Archaeopteryx, Confuciousornis, Protopteryx are transitional between reptiles and birds (Illustrated in a few slides.)• Eusthenopteron (fish) is linked to the early amphibian Icthyostega; Acanthostega• Genera such as Probainognathus, Probelesodon and Massetognathus (cynodonts) are transitional between reptiles and mammals

The fossil record yields…The fossil record yields…

Biogeographical Biogeographical Evidence coupledEvidence coupledto fossil recordto fossil record

hummingbirdshummingbirdsmarsupialsmarsupials

Quick note on the phenotypeQuick note on the phenotype

VVpp = V = Vgg + V + Vee + V + Vggxxee

g e pg e pA ∙ M A ∙ M X XB ∙ M B ∙ M Y Y

A ∙ M A ∙ M X XA ∙ N A ∙ N Y Y

Gradual versus punctuated evolutionGradual versus punctuated evolution

• Gradual change over time

• Branching, punctuated change

Mesonychid – shared ancestry with whalesMesonychid – shared ancestry with whales

AmbulocetusAmbulocetus

Rodhocetus, a predominantly aquatic whale from the Eocene (47 mya)

Vestigial pelvis and femur in modern whales

Many dinosaur bones have been found . . .

(Ultrasaurus)

Archaeopteryx

Comparative anatomyHomology having common ancestry but not necessarily retaining similarity of structure or function

The AdultExamples:• Mammalian forelimbs (“hands”)

o grasping hands of primateso digging hands of moleso locomotive hands of horseso paddles of porpoiseso wings of bats

• Vertebrate hindlimb structure

Hind Limb Structure in Vertebrates

Homo Homo sapienssapiens

The Embryo

Bio-molecular Evidence

•Protein evidence

•Nucleic acid evidence

•Others…

RELATIVE LEVEL OF RELATIVE LEVEL OF SHARED CHARACTERISTICS AMONG SPECIESSHARED CHARACTERISTICS AMONG SPECIES

DNA Phylogeny

EVIDENCE FOR EVOLUTIONEVIDENCE FOR EVOLUTION

1. Fossil Record2. Comparative Anatomy (phenotype)

physiology, anatomy, behavior, etc…3. Biogeographical4. Biochemical