what is the origin of life?

1.A branch of knowledge dealing with a body of facts or truths systematically arranged.

2.Systematic knowledge of the physical or material world gained through observation and experimentation.

3.Knowledge, as of facts or principles; knowledge gained by systematic study.

science

scientific method

the unknown past

Scientists who study the past need to use different methods than those who study things that are observable.

They are like detective, putting clues together, trying to paint a picture of what occurred. They use what they know about the evidence and what they know about cause-and-effect relationships.

How do we test something that occurred in the past? something that occurs very slowly?

We must use historical science to determine what happened in the past.

historical science

When you lay on the couch to take a nap, the sun is shining brightly.

You awake and look outside.

evidence 1: the driveway is covered in water

and

evidence 2:the car in the driveway is also wet

historical science

What can you conclude?

it rained while you slept

or

the automatic sprinklers came on

historical science

But then you see the following:

evidence 3:the lawn and the street are perfectly dry

and

evidence 4:there are no clouds in the sky

historical science

Now what?

Rain storm and sprinkler are still possible

but

are less likely because of evidences 3 and 4

(lawn dry & no clouds)

historical science

You look at bit harder and see

evidence 5:a bucket with soapy water

and a sponge behind the car

historical science

Now with the last piece of evidence (the soapy bucket),

it is much more obvious:

Someone washed the car.

historical science

This is an example of making an guess about the past using

historical reasoning.

You missed what happened, because you were asleep, but

there remains some clues.

historical science

Using those clues, your job is to come up with the best explanation.

You start with the evidence and with other knowledge you have

about the world.

You work backwards to infer what probably happened when you were not there to observe it.

historical science

The best explanation will be the one that explains most of the evidence.

historical science

What are the various viewpoints on the origin of species?

a doctrine or theory holding that matter, the various forms of life, and the world were created by God out of nothing and usually in the way described in Genesis

creationism

intelligent designThe theory of

intelligent design holds that certain

features of the universe and of

living things are best explained by an

intelligent cause, not an undirected

process such as natural selection.

evolution

Biological evolution is descent with modification.

This definition encompasses

small-scale evolution,

microevolution - changes in gene frequency in a

population from one generation to

the next and...

evolution

...large-scale evolution macroevolution - the descent of different species from a common ancestor over many generations.

evolution

Biological evolution is not simply a matter of change over time. Lots of things change over time: trees lose their leaves, mountain ranges rise and erode, but they aren't examples of biological evolution because they don't involve descent through genetic inheritance.

evolution

The central idea of biological evolution is that all life on Earth shares a common ancestor.Through the process of descent with modification, the common ancestor of life on Earth gave rise to the diversity of the various species.

evolution

who was the main person to put evolution on the table? charles darwin What book did Darwin

write explaining his theory of evolution? On The Origin of Species

darwin’s travels england

HMS Beagle

Darwin studied 13 species of finches. They were all similar, except for their:

darwin’s theory:

evolution through natural selection

body sizebeak shapeeating habits

evolution through natural selection

Darwin thought the varieties of plants and animals could be best

explained by descent from a common ancestor.

He used the plants and animals of the Galapagos

Islands as an example.

darwin’s theory:

The mechanism Darwin thought that was responsible for evolution was Natural Selection.

He argued that it had the power to make new forms of life.

darwin’s theory:

evolution through natural selection

Darwin’s idea became known as the Theory of Evolution by Natural Selection.

Natural Selection means that organisms with traits best suited to their environment are more likely to survive and reproduce.

Overtime, as new data was gathered and reported, changes were made to Darwin’s original ideas about evolution by natural selection.

natural selection

principles of natural selection1. Organisms produce more offspring than can survive.

2. Differences, or variations, occur among individuals of a species.

3. Some variations are passed to offspring.

4. Some variations are helpful. Individuals with helpful variations survive and reproduce better than those without these variations.

5. Over time, the offspring of individuals with helpful variations make up more of a population and eventually may become a separate species.

An adaptation is any variation that makes an organism better suited to its environment.

adaptation

Over time, the genetic makeup of a species might change its appearance.

Many kinds of environmental factors help bring about changes.

When individuals of the same species move into or out of an area, they might bring in or remove genes and variations.

adaptation

A variation is an inherited trait that makes an individual different from other members of its species.

Variations result from mutations.

Some gene changes produce small variations, such as differences in the shape of human hairlines.

Other gene changes produce large variations, such as an albino animal in a population of normal colored animals.

If individuals with these variations continue to survive and reproduce over many generations, a new species can evolve.

variations

darwin’s theory has evolved Darwin did not understand genetics, like you do.

He did not know how traits are passed from one generation to another.

Once scientists learned more and more about genetics and mutations, Darwin’s Theory was modified.

The modern theory is called neo-Darwinism.

The theory of evolution based on Darwin’s original theory of evolution of species through the process of natural selection together with current understandings and theories of genetics and inheritance.

neo-darwinism

which theory is right?

There still remains much debate over the origin of species.

Sometimes the evidences can be explained in more than one way -- this is where different theories and debates are made.

The claims of the theories cannot be tested, but by looking at all the evidence carefully, we can decide which theory seems more logical.

Our goal, grade 8 students, is to examine the scientific evidences and make our own educated decisions on the origin of life.

which theory is right?