7.1 How it al began 2HVTTO

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• Leerjaar 2

7.1 How it all began

• Take off your jacket

• Put your things on your desk

       Laptop/Books,

notebook, pencil case

• Bag on the floor

• Read Only pages 177-180

5

minute

00

second

add30s

Lessongoals

• Remembering – I can define variation, adaptation and natural selection.

• Understanding – I can explain how natural selection leads to adaptation in a population.

• Analyzing – I can compare structural and physiological adaptations using one example of each.

• Analyzing – I can explain how new species can form when populations become isolated.

Homework 7.1

Asgmt 1-7, (4)

Senna dyes her hair blond. Weeks later, she has her original hair colour again. What has happened?

A

The genotype changed, later the phenotype changed the genotype back to how it was

B

The phenotype changed, later the phenotype changed the genotype back to how it was

C

The phenotype changed, later the genotype changed the phenotype back to how it was

D

The phenotype changed, later the phenotype changed the phenotype back to how it was

Which cells in the body contain genes for body size? Pick the most correct answer

A

Cells in the legs

B

Cells in the legs and bones

C

Cells in the legs, bones and brain

D

Cells in the legs, bones, brain and eyes

Cell 1 is an eye cell with chromosomes of an unknown organism.

What would a cell in the intestines of this organism look like?

A

Like cell 1

B

Like cell 2

C

Like cell 3

D

like cell 4

Cell 1 is an eye cell with chromosomes of an unknown organism.

What would a sperm cell of this organism look like?

A

Like cell 4

B

Like cell 2 or 3

C

Like cell 3 or 4

D

Like cell 3

Each gene has many variants (blond, brown, ginger, etc). If you were able to look in someone's DNA and see the variants of 1 gene pair. What would be the highest amount of variants you could find?

A

1

B

2

C

3

D

4

Both parents are homozygous for blond hair. How big is the chance for their kid to be homozygous for blond hair too?

A

0%

B

25%

C

75%

D

100%

Mother is homozygous and has blond hair Father is heterozygous and has blond hair Is it possible for their kid to have a different hair colour than blond?

A

Yes

B

No

C

D

The theory of evolution

1

Comparable to a fairy tale

2

I don't really know what it is, so I don't have an opinion

3

I'm not entirely sure about it. But don't think it's made up

4

I'm very sure it's absolute truth

5

other

Evolution has to do with ..

Theory of evolution is about...

• The emergence of new species (all organisms)

• The way in which these species arise

• Determining which species are related to each other

emergence = the fact of starting to exist or becoming known for the first time

Evolution is NOT about ..

• How life came to be

• How the universe/solar system/earth/etc. came to be

• If a God exists

3 main mechanisms

Evolution can be summarized  into these 3 mechanisms:

1. Variation in genotypes

2. Natural selection

3. New species arise

Variation in genotypes

• Sexual reproduction and mutations > new/different genotypes

• New genotypes > new/different phenotypes

• Lots of changes in genotype >    DNA changes 'too' much > new species

Sexual reproduction = reproduction in which two sex cells from two different organisms join together to form a new organism.

Because of meiosis, many different sex cells are made inside one organism. These cells are then combined by chance with the sex cells of another organism.

This creates new organisms with different DNA (new genotypes).

When the genotype is different, the phenotype (how an organism looks or functions) can also be different.

That’s why even organisms from the same species are all a little bit different.

If the genotype or DNA changes too much, it can become so different that the organism becomes a new species.

Note: This usually takes a very long time – thousands of years.

For example, the Darwin finches were once all the same species.

Because of changes in their genotypes, the shape of their beaks (their phenotype) slowly changed.

Nowadays, there are many different kinds of finches, but they were once all the same species.

Natural selection

• Species who have adapted to 

   their environment will survive

    and reproduce

• 'Good' genes are passed on

• 'Bad' genes dissapear

Being “adapted” depends a lot on the environment!

A thick fur is useful in a cold environment, but not in a hot one.

Pointy teeth are only useful if you eat meat.

A big and strong body only helps if you can also find enough food.

!

What is the deciding 'thing' that tells you that two organisms belong to the same species?

New species arise

more examples

1. Animals of a species live in a certain area

2. Animals of same species are  split up into separate areas

3. The environment slowly changes.
   Because of natural selection, other genes are 'good' in new environment

4. Species have become different species after many years of evolution, due to living apart

New species arise

• New species arise due to LONG periods of evolution in a species

• Many small changes together become big changes

• Evolution takes very long! (thousands of years)

This image makes me think ..

Theory of evolution

1

Still comparable to a fairy tale

2

I understand it better, still don't really believe it

3

I don't understand it entirely, but seems logical

4

This seems a very logical explanation for how we got all the organisms we have today

What you should do: 7.1

• TB: Pages  177-180

• WB/Lt: Asgmt 1-5, 8, 11, 16, 17

• Try natural selection

Done with the above?

• Work on the next chapter(s)

• Learn for the test 

• Make other homework

• Read a book

Zs = Working in Silence

• No asking questions

• Silent, don't disturb anyone

• Stay at your  desk

6

minute

00

second

add30s

What you should do: 7.1

• TB: Pages  177-180

• WB/Lt: Asgmt 1-5, 8, 11, 16, 17

Done with the above?

• Work on the next chapter(s)

• Learn for the test 

• Make other homework

• Read a book

Zw = Working with whispering

• Teacher is available for questions

• Only whisper with the student next to you

• Stay at your  desk

Some people find evolution hard to 'believe' in, because they don’t really 'see' it happening. Why is evolution so hard to 'see' for most people?