WHAT IS EVOLUTION?

Evolution is a change in gene pool over time.

It also is the idea that new species develop from earlier

species, sometimes referred to as “descent with

modification”

FAQ: Isn’t evolution only a theory?

It is a fact in the respect that yes, it has indeed occurred and is occurring on a daily

basis.

It is a theory in the respect that scientists disagree on the

details of how it occurred.

Remember what a theoryin science is - a well-substantiated explanation of some aspect of the natural world that can incorporate facts, inferences, and tested hypotheses* (not a hunch or guess)

*(National Science Foundation)

Next Battleground: Dover, PA

Next Battleground: Dover, PA

Dover trial began on Monday:Sept. 26,

2005

The Scope and Limitations of Science Are More Than An Academic Issue

The Scope and Limitations of Science Are More Than An Academic Issue

What is the evidence of evolution?

1) The Fossil Record

2) A Universal Genetic Code3) Common Molecular Sequences4) Transitional Fossils

The Fossil Record and Transitional Fossils

Evidence - A transitional fossil linking past and present

The Branched Evolution of Horses

Evidence - Molecular Data and the Evolutionary Relationships of Vertebrates

Evidence - Homologous Structures: anatomical signs of descent with

modification

Homologous Embryos

Evidence - Evolution of insecticide resistance in insect populations

Evidence - The evolution of fruit fly (Drosophila) species on the Hawaiian

archipelago

•Vestigial Organs/StructuresIncluding:

•Appendix•Wisdom teeth

•Male nipples• Rudimentary ear muscles• Coccygeal (tail) vertebrae

•Thirteenth Rib (vs. 12)

•Body Hair •Palmaris Muscle – for climbing and is missing in 11% of humans• Pyramidalis Muscle – more than 20% of humans lack this relic from marsupials

•Subclavius Muscle – in the shoulder region; useful for tetrapods

Vestigial Structures(continued)

•Third Eyelid – a common ancestor of birds and mammals may have had a membrane for protecting the eye

•Plantaris Muscle – for grasping has disappeared in 9% of humans

•Neck Ribs – appear in 1% of the population

Vestigial Structures (continued)

FAQ: Are you going to teach us that we are

descendants of apes?

•No, That’s an inaccurate concept-ion of evolutionary theory. We have the closest common ancestry withthe great apes

A Molecular Test of Common Ancestry

Chromosome Numbers in the Great Apes:

Human (Homo) 46

Chimpanzee (Pan) 48Gorilla (Gorilla) 48Orangutan (Pogo)48

Testable prediction: If these organisms share a common ancestor, that ancestor had 48 chromosomes (24 pairs)

Chromosome Numbers in the great apes

(Hominidae):

Human (Homo) 46Chimpanzee (Pan) 48Gorilla (Gorilla) 48Orangutan (Pogo) 48

Testable prediction: If these organisms share a common ancestor, that ancestor had 48 chromosomes (24 pairs)

Centromere

Telomere

Ancestral Chromosomes

FusionHomo sapiens

Inactivated centromere

Telomere sequences

Hillier et al (2004) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.

Chromosome Numbers in the great apes

(Hominidae):

Human (Homo) 46Chimpanzee (Pan) 48Gorilla (Gorilla) 48Orangutan (Pogo) 48

Hillier et al (2004) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.

“Chromosome 2 is unique to the human lineage of evolution, having emerged as a result of head-to-head fusion of two acrocentric chromosomes that remained separate in other primates. The precise fusion site has been located in 2q13–2q14.1 (ref. 2; hg 16:114455823 – 114455838), where our analysis confirmed the presence of multiple subtelomeric duplications to chromosomes 1, 5, 8, 9, 10, 12, 19, 21 and 22 (Fig. 3; Supplementary Fig. 3a, region A). During the formation of human chromosome 2, one of the two centromeres became inactivated (2q21, which corresponds to the centromere from chimp chromosome 13) and the centromeric structure quickly deterioriated (42).”

Homo sapiens

Inactivated centromere

Telomere sequences

FAQ: If we have a common ancestor with apes, why are therestill apes?

FAQ: Doesn’t “believing” or “accepting” evolutionary theory mean you don’t believe in God?

No, most mainstream religionsaccept modern evolutionarytheory it premises

FAQ: Why can’t we learn creationism and evolution? Should “equal time” be devoted to both?

FAQ: Isn’t evolution alwaysimproving organisms?Not always, but there is a drivetowards a particular phenotype.

Evolution is a result of the interactionsbetween species and their current environments. If theseconditions change, an apparentevolutionary trend may ceaseor reverse itself.

FAQ: Why is it that important anyway?

- molecular (DNA)biology-cellular biology-genetics-taxonomy- physiology

Evolution is a central unifying theme incorporating:

Evolution Is Biology’s Unifying PrincipleEvolution Is Biology’s Unifying Principle

“Nothing in biology makes sense except in the light of

evolution.”

Theodosius Dobzhansky, 1973

How is evolution both a fact anda theory? What is meant by the word, “theory”?

What was the last major court case dealing with teaching evolution in schools? What was the ruling?

List two major pieces of evidence that demonstrate evolution has occurred.

Place the following events in chronological order from first to most recent using “Pacing Geologic Time”

•evolution of reptiles•evolution of mammals•evolution of birds•evolution of amphibians•first flowering plants

Know These in Chronological Order:•evolution of eukaryotes•first multicellular life•earliest fish•first amphibians•first reptiles•first dinosaurs•first mammals•earliest birds•first flowering plants•early primates•earliest humans

1)Calculate the percentage of time that humans have been on the earth.

2) The fossil record supports the theory that all multicellularevolved within the past ______

million years.

Classify a snake fromits proper domain down to its class.

Organisms that start their lives in water and move onto land are called ….

Pacing Geologic Time Answers

1)3500 million years ago (3.5 billion)3) 2800 million (3500 mill – 700 mill)5) The geologic events are furtherapart6) 3.5 million X 100 = .07% 4600 million 7) amphibians, reptiles, mammals,birds.