The Nature of Science and the Science of Nature

• Read 274-298

• Pay attention to “overview” pg 276 and 290

4 goals in the investigation of zoology(and other life sciences)

• 1. Cataloguing diversity (Taxonomy)

• 2. Explaining the functions of the body (Anatomy Physiology)

• 3. Relating environmental influences to forms (Ecology)

• 4. Understanding patterns and processes in the world. Ex. Inheritance, photosynthesis, fossil record, erosion, volcanism,)

EVOLUTION

• fundamental unifying concept in biology. A great variety of observations can be explain because of this theory

• - doesn’t really comment on origins

• - all organisms are related by genealogy (ancestry)

• - "descent with modification " Darwin (features of a population changeover time in response to environmental conditions)

I. THE EVOLUTION VS. CREATION DEBATE• A. The theory of

EVOLUTION has stirred much SOCIAL controversy in the past

• The Scopes Monkey Trial

• "God, Darwin and Dinosaurs” video

• Begin video • (Show 1st 20 min. up to Karl Popper)

IN a nut shell , here is the conflict…

• Supernatural creation of the universe and its contents

• vs. • natural processes

originating, and modifying life to the point we see it today.

Arkansas LAW 590 "Balanced treatment law"

• Required that creationist accounts be taught in biology classes because

• “In the beginning, God created the Heavens and the Earth” is also a theory.

• This Law was struck down on January 5th,1982.

• The video will help explain why Judge Overton made that ruling.

• B. A semantic problem (a problem with the

definition of the word) THEORY• According to creationists--- Creation is

as valid an explanation of the origin of life as evolution

THEORY

• - A TESTABLE EXPLANATION OF A BROAD RANGE OF RELATED PHENOMENA. IN MODERN SCIENCE, ONLY EXPLANATIONS THAT HAVE BEEN EXTENSIVELY TESTED AND CAN BE RELIED UPON WITH A VERY HIGH DEGREE OF CONFIDENCE ARE ACCORDED THE STATUS OF A THEORY.

examples

• The Cell Theory• The Atomic Theory• Continental Drift

DEFINITIONS OF OTHER IMPORTANT WORDS

• LAW- a statement that describes the behavior of some particular thing or set of things within the natural world, with an adequately thorough history of successful scientific replication.

• HYPOTHESIS- an idea or explanation for something that is based on known facts but has yet been proven

• FAITH - a belief in the absence of fact or data• THEORY- a belief based on data or fact

• Don’t write this 1st sentence

• Theory: A theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers. One scientist cannot create a theory; he can only create a hypothesis. A theory is more like a scientific law than a hypothesis.

• Don’t write this 1st sentence

• Hypothesis: This is an educated guess based upon observation. It is a rational explanation of a single event or phenomenon based upon what is observed, but which has not been proved. Most hypotheses can be supported or refuted by experimentation or continued observation.

• Scientific Law: This is a statement of fact meant to explain, in concise terms, an action or set of actions. It is generally accepted to be true and universal, and can sometimes be expressed in terms of a single mathematical equation. Scientific laws are similar to mathematical postulates. They don’t really need any complex external proofs; they are accepted at face value based upon the fact that they have always been observed to be true.

• Specifically, scientific laws must be simple, true, universal, and absolute. They represent the cornerstone of scientific discovery, because if a law ever did not apply, then all science based upon that law would collapse.

• Some scientific laws, or laws of nature, include the law of gravity, Newton's laws of motion, the laws of thermodynamics, Boyle's law of gases, the law of conservation of mass and energy, and Hook’s law of elasticity.

Reference page

• The biggest difference between a law and a theory is that a theory is much more complex and dynamic. A law governs a single action, whereas a theory explains an entire group of related phenomena

C. The Creationists views (be able to distinguish between the two approaches)

• 1. CREATIONISM

• -supernatural creation of the universe and its contents

• - literal interpretation of the Bible

• - short history of the earth

Show 2nd 20 minutes of video, end at mosquito larva

• 2. SCIENTIFIC CREATIONISM

• scientific evaluation of data reveals that

• - the earth is young (other methods of dating are wrong)

• - fossils appear at the same time (humans and dinosaurs)

• - supports the Biblical account of creation

D. A simple contrast table

• EVOLUTION VS. CREATIONISM

EARTH OLD YOUNG

SPECIES CHANGED UNCHANGED

ORIGIN GRADUAL ALL AT ONCEOF SPECIES

CAUSE NATURAL INTELLIGENT• PROCESSES DESIGN

II WHAT SCIENCE IS (and why creation science is not science)

• What is with-in the realm of science and what is not?

• What are the methods of science?

• Science is, what scientists do!

• 1. Classify

• 2. Understand

• 3. Unify the objects and phenomena of the material world

A. Characteristics of Scientific Investigation

• 1. Materialism- GROUNDED IN THE LAWS OF NATURE such as gravity, magnetism, entropy, strong and weak nuclear forces

• 2. Testability- dependent parts and be individually tested for validity.

Events can be measured, interpreted, extrapolated(applied to a broader range of

experiences) ex. DNA changes = hereditary change, nuclear decay = dating the age of rocks

• 3. Flasifiability- the potential to be proven wrong

• the approach to solving a problem is most important, not the final result.

• repeatable experiments• data= facts• conclusions are only as good as the data• results are provisional (temporary)- • not a problem because new information is

always being accumulated• 4. Peer review of research- other experts

critiqueresearch before allowing publication

Show final 20 min segment of video

• B. Appropriate and inappropriate questions• NOT POSSIBLE• 1. morality 1. What is light?• 2. ethics 2. Why do we see

stars?• 3. free will 3. How deep is the

ocean?• 4. imagination 4. What is needed for

proper human growth?• 5. spiritual 5. What are the

products of combustion?• 6. metaphysical 6. How fast can a zebra

{GHOSTS} run?

C. Fallacy of Creation-Science-

• they already have an answer before the facts are discovered

• the data will not change their conclusion

• creation cannot be wrong

• research is not published in peer reviewed journals

D. Intelligent Design (ID)- latest form of Creationism

• Suggests life is too complex to have originated and developed by chance.

• Therefore it must have been “designed”

• Recent battle about the science standards in Ohio

• Court ruling in Dover, Pennsylvania

IV THE CORE OF MODERN BIOLOGY #2 EVOLUTION

• We don't often think of the questions that biologists are trying to answer.

• They are responses to observations of the natural world.

1. UNITY - why do organisms look similar?

• Why the same 20 amino acids?• why do all organisms possess the same DNA

and RNA?• why is energy in the form of ATP and GTP?

2. DIVERSITY

• how did we get 30 million species?

• What drives them to diversify?

• They are all unique from large to small.

3. BIOLOGICAL ADAPTATIONS

• why do organisms possess features that help them survive in their area?

• How do bacteria become antibiotic resistant?

• How long does it take?

4. HISTORY

• What happened in the past?

• We didn't witness the events but can we figure out the event in the past?

• Ex. fossils, geological formations, extinction, ice ages

V The Logic of Natural Selection pg 28

Complete work sheet from the binder “The Theory of Evolution”

What are the basic components of Darwinian Evolution by Natural

Selection?• FACTS• 1. Superfecundity- (means overproduction of offspring)

• resources grow arithmetically 1,2,3,4,5,6,7,8• populations grow geometrically 1,2,4,8,16,32,64

• 2. Individual variability

• 3. Heritability

Theory of Natural Selection

• adaptation to local circumstances • not towards greater complexity• 1) Competition for Resources Thomas Malthus

ex. economist

• 2) Survival in part is determined by characteristics, characteristics can be passed. Therefore the next generation has more members with the particular characteristics that helped the original survive

• 3) The character and composition of the population changes. Gene frequencies change.

• (evolution is occurring) (individuals don't evolve, populations do)

Evidence of relatedness

• Example: Transitional forms in the fossil record

Hypothesis: If terrestrial vertebrates (tetrapods) evolved from lobe-finned fish (sarcopterygians), then there should be transitional forms that possess traits that are intermediate.

Previously identified transitional forms

From Ahlberg and Clack, Nature 2006

General Methods

• Scientists looked specifically for the transitional form of interest by sampling…– Appropriate habitats

(stream system)– Appropriate geologic time

(early Late Devonian = 385-376mya)

From Daeschler et al., 2006

http://tiktaalik.uchicago.edu/photos.html

They found Tiktaalik roseae!

From Ahlberg and Clack, Nature 2006

From Daeschler et al., Nature 2006

http://tiktaalik.uchicago.edu/photos.html

From Shubin et al., Nature 2006

http://tiktaalik.uchicago.edu/photos.html

Summary

• The study of and the evidence for evolution clearly fits within the scientific framework.

• We use current evolutionary theory to make and test hypotheses

• There are many thousands of examples of evidence for evolution

What data from whole genome sequencing can tell us about evolution of humans

What data from whole genome sequencing can tell us about evolution of humans

Example: the Evolutionary Hypothesis

of Common Ancestry

Chromosome Numbers in the great apes:

human (Homo) 4646chimpanzee (Pan) 48gorilla (Gorilla) 48orangutan (Pogo) 48

Testable prediction:Testable prediction: If these organisms share a common ancestor, that ancestor had either 48 chromosomes (24 pairs) or 46 (23 pairs).

Testable prediction:Testable prediction: If these organisms share a common ancestor, that ancestor had either 48 chromosomes (24 pairs) or 46 (23 pairs).

Chromosome Numbers in the great apes (Hominidae):

human (Homo) 46chimpanzee (Pan) 48gorilla (Gorilla) 48orangutan (Pogo) 48

Testable prediction:Testable prediction: Common ancestor had 48 chromosomes (24 pairs) and humans carry a fused chromosome; or ancestor had 23 pairs, and apes carry a split chromosome.

Centromere

Telomere

Ancestral Chromosomes

FusionHomo sapiens

Inactivated centromere

Telomere sequences

“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).”

“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

Hillier et al (2005) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.

Hillier et al (2005) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.

Human Chromosome #2 shows the exact point at which this fusion took place

Human Chromosome #2 shows the exact point at which this fusion took place

Chr 2

• STUDY GUIDE• Define Creationism, Creation Science, Evolution,

Natural Selection, theory, law, hypothesis• Contrast Evolutionists and Creationists view of

earth and its components.• Describe the history, circumstances and

outcome of the "Scopes Monkey Trial"• List 4 components of a scientific investigation• List 4 main questions biologists ask • Describe Evolution by Natural Selection (give

Darwin’s facts, evidence, and argument)• Define Intelligent design