7.1 How it all began

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

odd one out 

what do they have in common? 

00:55

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

Inference 2

DIFFERENTIAL 

REPRODUCTION

natural selection 

--> every individual is unique

--> differences in traits  are inheritable 

---> 1.  variation in inheritable traits 

i.e. there are green and brown beetles 

---> differential reproduction 

i.e. 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 

--> final result 

i.e. 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 

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

different types of adaptations

structural:  

      changes of body parts 

      mimicry : a species resembles another species 

physiological: 

      changes in cell metabolism

--> what type of changes do you see in the next video? 

• If you cut off a rat’s tail will its babies have no tail?  
  
• If I straighten my hair every day is there a chance that my children will have straight hair? 

Darwin vs Lamarck

Darwin: natural selection of inherited traits

Lamarck: 

- use and disuse : individuals lose characteristics they do not require and develop the ones that are useful

- inheritance of acquired traits : individuals inherit the traits their ancestors acquired during their lifetimes 

How might Darwin have explained the ability of birds of prey to fly very fast?

• birds of prey need to fly fast to catch prey
• within the bird of prey species, some individuals can fly faster than others. These faster birds catch more food, do better and have more offspring. Such offspring, at least to some extent, inherit their parents ability.
• Over the generations the birds evolve the ability to fly very fast 

How might Lamarck have explained the ability of birds of prey to fly very fast?

• birds of prey need to fly fast to catch prey
  
• over their life time, birds develop the appropriate large flight muscles and other key features to pass on, at least to some extent, to their offspring
• over the generations the birds evolve the ability to fly very fast 

homework

Read section 7.1 

Do q. 1, 2, 3, 5, 6