5.5 How it all began

• Biologie
• biology
• Middelbare school
• vwo
• Leerjaar 3

All organisms are slightly different. We call this ...

1. Heredity
2. Inheritance
3. Variation
4. Genes

Is it a gene or an allele?

GENE

ALLELE

skin colour

curly hair

flower colour

blue eyes

blood type

type A blood

colour-blindness

hair type

short wings in a fruit fly

Oliver says: 'all humans have the same genes, but not the same alleles'. Charley says: 'all humans have the same alleles, but not the same genes'.
Who is right?

1. Oliver
2. Charley
3. They both are
4. They are both wrong

Each human being has 46 chromosomes. How many did you get from your mother?

1. 46
2. 23
3. 22
4. 45

genotype

phenotype

XY chromosomes

cannot change!

you inherit this

can sometimes change during your life

you do not inherit this

a scar

Is not always visible

A cell with an X chromosome and a Y chromosome, can be a

1. muscle cell
2. sperm cell
3. egg cell
4. no cell

Homozygous dominant:

1. RR
2. Rr
3. rr

Who is this man?

00:55

what are the two basic ideas of Darwin's evolution?

Put the events of Darwins life in the correct order. You can use your book!

Trip with the HMS beagle

Noticed diverstity

Visited Galapagos

Concluded species change

Darwin arrived back in England

Published 'the origin of species'

What do you need for Natural Selection

1. To be the biggest
2. To be unique
3. Being able to pass on genes
4. To adapt when you're still alive

natural selection 

--> every individual is unique (no clones)

--> differences in traits  are inheritable 

(Heredity) 

---> 1.  differences in inheritable traits 

i.e. there are green and brown beetles 

What will happen to the beetle population, when a bird comes by that only eats green beetles?

1. There will be more brown beetles
2. There will be more green beetles
3. The beetle population will stay the same
4. The beetle population will go extinct

green beetles tend to get eaten by birds and 

survive to reproduce less often than brown beetles

and surviving brown beetles have brown baby

beetles 

the more advantageous brown colouration which allows the brown beetle to have more offspring becomes more common in the beetle population. 

If this process continues, eventually, all individuals in the population will be brown 

--> Differential reproduction

fernandina

-> small fruit

santiago/san salvador

--> small seed

santa cruz

--> worms

pinta

--> large fruit

fernandina

-> small fruit

santiago/san salvador

--> small seed

santa cruz

--> worms

pinta

--> large fruit

Which finch belongs to which island?

fernandina

-> small fruit

santiago/san salvador

--> small seed

santa cruz

--> worms

pinta

--> large fruit

Interesting structures

• Homologous: divergent evolution
  similar origin, different function
• Analogous: convergent evolution
  different origin, similar function

HOMOLOGOUS STRUCTURES

ANALOGOUS STRUCTURES

homework

Read Paragraph 5.5 and make the questions in your book

prepare for the test