The Theory of Evolution

Charles Darwin (1809 1882) The most famous scientist that studied and discussed

evolution is Charles Darwin. He was a British scientist who laid the foundations of the theory of evolution and transformed the way we think about the natural world.

Darwin himself initially planned to follow a medical career, and studied at Edinburgh University but later switched to theology at Cambridge. In 1831, he joined a five year scientific expedition on the survey ship _______________________________.

At this time, most Europeans believed that the world was created by _______________________________________________________________ as described in the bible.

However, on his voyage, Darwin read the 'Principles of Geology' which suggested that the _______________________ found in rocks were actually _______________________ of animals that had lived thousands or millions of years ago.

This concept was reinforced in Darwin's own mind by the rich variety of animal life and the geological features he saw during his voyage.

The breakthrough in his ideas came in the Galapagos Islands, 500 miles west of South America. Darwin noticed that each island __________________________________________________________ which were closely related but differed in important ways.

Evolution continued: Darwin observed that Finches had

different beak sizes on different islands dependent on the food resources available to them.

On his return to England in 1836, Darwin tried to solve the riddles of these observations and the puzzle of how species evolve. He eventually proposed a theory of evolution occurring by the process of ____________________________________.

The animals (or plants) best suited to their environment are more likely to survive and reproduce, passing on the ______________________________ which helped them survive to their offspring.

Gradually, the species ________________ over time.

In 1859 Darwin published 'On the Origin of Species by Means of Natural Selection'.

The book was extremely controversial, because the logical extension of Darwin's theory was that homo sapiens was simply another form of animal. It made it seem possible that even people might just have evolved - __________________________________________ - and destroyed the prevailing orthodoxy on how the world was created.

Darwin was vehemently attacked, particularly by the _____________________. However, his ideas soon gained currency and have become the new orthodoxy.

What is a theory? As we have seen Darwin’s research

followed from an interesting theory. In everyday use, the word "theory" often means an untested hunch, or a guess without supporting evidence.

But for scientists, a theory has nearly the opposite meaning.

A theory is a____________________ ______________________________. It can incorporate laws, hypotheses and facts.

What is evolution: Evolution is the

___________________________________ of organisms over time.

This genetic change may give the organism a survival and/or reproductive ________________________ in their ___________ environments.

Population increases usually accompany these changes and this increased rate of survival is known as natural selection.

The Theory of Evolution:

Supporters of the theory of evolution believe that all living things developed from __________________________ form of life.

From this ‘unknown’ ancestor organisms adapted according to their environment and gave birth to the diverse species seen in the fossil record.

The Theory of Evolution: There are 4 essential requirements of evolution:

V = _______________________: All life forms vary genetically within a population. It is this genetic variation upon which selection works.

I = ________________________: Genetic traits are inherited from parents and are passed on to offspring.

S = _________________________: Organisms with traits that are favorable to their survival get to live and pass on their genes to the next generation.

T = ______________________: Evolution takes time. Evolution can happen in a few generations, but major change, such as speciation, often takes long periods of time.

The Theory of Evolution: There are also four ways in which evolution

occurs:1) Mutation: a change in an organisms DNA usually

caused by an_______________ in repair or duplication

2) _______________________: occurs when an organism inserts its DNA in a different species pool

3) Genetic Drift: random changes in gene frequencies of a species (could be caused by ____________________________________)

4) Natural Selection: process in which some individuals have genetically-based traits that ____________________________ or reproduction and thus have more offspring

The Theory of Creation:

Many people believe in creationism. This is the belief that man (and all other

beings) were _________________________ ____________________________________

For many this belief is grounded in the book of Genesis.– Chapter 1, Verse 27: “So God created man in his

own image, in the image of God created them; male and female created them.”

The Theory of Creation: Believers in creation suggest that the major

plants and animals on earth were placed on the earth in their final form.

This also suggests that man/women were placed on the earth in his/her current fully human form.

In this view, earth was not a spontaneous creation but rather a specific and ______________________ event by our creator.

Theories on the Origin of Humankind – Pre-Darwinism Diluvial Theory:

– supported the Bible– fossils of extinct animals formed by

______________________________

Objections: – no single event like Flood could account for

progression of fossils in layers, each lower level is older

– discovery of pre-flood fossils related to animals living after the flood

Theories on the Origin of Humankind – Pre-Darwinism

_________________________ Theory – George Cuvier (1769-1832)– explained sequence of fossil layers by proposing a

corresponding series of major catastrophes interspersed with periods of calm when plant and animal populations restocked the Earth

– Noah’s flood just one of many catastrophes (between 27-32)

Objection:– fossil record looks like “jerky” catastrophes but

change was much ________________________

Contemporary Creationism

________________________ Design– promotes the idea that natural processes

and living things are best explained by an intelligent cause and not undirected, Darwinian natural selection

Common Objection: not scientifically __________________________, should not be considered a “scientific theory”

What is the big deal anyways? Why was (is) the theory of evolution so controversial?

– At the time of Darwin’s publication of the Origin of Species (1859) creation was the most widely accepted version of how the earth and all life on it was created.

– To many it seemed that the theory of evolution was an attempt to contradict religious belief.

– But, Darwin himself was deeply religious.– The idea that humans came from apes was also offensive to some

people.

Misconceptions about the theory of Evolution:1. Evolution is a theory about the origin of

life.

Misconceptions continued:

2. Evolution is like a climb up a ladder of progress; organisms are always getting

better.

Misconceptions continued:3. Evolution means that life changed ‘by

chance’.

Misconceptions continued:

4. Natural selection involves organisms ‘trying’ to adapt.

Misconceptions continued:5. Natural selection gives organisms what

they ‘need’.

The Evolutionary Algorithm:

If you have:– Variation– Inheritance– SelectionAnd- Time

Then you get evolution

Activity: Refer to the chart attached where you

will find the progression of the human skull, take a few minutes to read it over.

Think about this question:

At what point in ‘the evolution of humans’ do you believe that these primates begin to become human? (Ex. when they begin to walk on two feet or use tools) Why?

Movie Clip – Human Spark

Activity – Questions on video.