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?

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

7. An epic journey 

• 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? 

What is natural selection?

Natural selection

Individuals that are best at surviving in their environment will produce more offspring 

Darwin vs Lamarck

Darwin: natural selection of inherited traits 'survival of the fittest'

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 

NATURAL SELECTION

Animals best adapted to 

their environment, live 

longer and have a better

chance at reproducing

Adaptation

"the process of change by which an organism or species becomes better suited to its environment"

"STRUCTURAL ADAPTATIONS"

• A CHANGE IN THE ANIMALS PHYSICAL BUILD & APPEARANCE.
• FOR EXAMPLE: HOW THEY LOOK, SHAPE OF BODY, ORGANS EVEN TEETH.

"PHYSIOLOGICAL  ADAPTATIONS"

• A SPECIAL ORGAN OR ABILITY (SUPERPOWER)
• FOR EXAMPLE: ECHO LOCATION, LOW WATER USAGE, NIGHT VISION, HOLDING BREATH A LONG TIME

Choose the correct adaptation:

1. STRUCTURAL
2. BEHAVIORAL
3. PHYSIOLOGICAL

What is a physiological adaptation of this rabbit?

1. White fur which camouflages him in the snow
2. His heart rate increases if he is chased by a predator so he can run faster
3. He hibernates during the winter
4. His teeth are sharp so he can eat raw vegetables

HAVING GILLS IS A STRUCTURAL ADAPTATION:

1. TRUE
2. FALSE
3. BOTH A AND B
4. NEITHER

homework

lrn par. 7.1 

read par. 7.2, do q. 1-4