1. Monday, February 8, 2016 HOMEWORK: None
OBJECTIVE: I will be able to explain what a variation is and its affects on a species by discussing the idea of selection pressure
DO NOW: Is variation important? Why or why not?

2. Variation How does variation affect survival?
How does variation affect reproduction?
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

3. Example 1: Tadpoles and Dragonfly Larvae
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

4. Dragonfly larvae
Dragonfly larvae are the larvae stage of dragonflies. Here is the life cycle of dragonflies.
Dragonfly larvae eat many things, including tadpoles.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

5. I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

6. Experiment 12 pools, each with 10 tadpoles
Scientists measured many traits of the tadpoles, including:
Body Width
Body Length
Tail Muscle Width
Color
Total Length
Then the scientists released three dragonfly larvae into 8 of the pools. 4 of the pools did not have any dragonfly larvae (control).
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

7. 12 Pools were set up. Each with 10 tadpoles each
Experimental set up
- Pond with 10 tadpoles
= Dragonfly larva in the pond
Three dragonfly larva (predator) were released into 8 of the 12 pools overnight
12 Pools were set up. Each with 10 tadpoles each
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

8. Larvae in Pond Overnight
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

9. Predator
Some tadpoles in each pond were eaten by the dragonfly larvae overnight
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

10. Tadpoles that survived versus tadpoles that got eaten?
No predator pool
Predator pool
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

11. Experiment
The next morning, they measured all the same traits of the tadpoles again to see if the ones that survived were different from the ones that got killed.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

12. Individually Answer Question #3 in Packet
Individually, read and complete the following question.
3. Two students were thinking about the tadpole study.
George said, “You can see that all the tadpoles are practically the same. On average, it’s a matter of luck as to which tadpoles get eaten and which survive. So the tadpoles in the pools with the dragonfly larvae will be about the same as the tadpoles in the pools without dragonfly larvae.”
Prutha said, “I don’t agree. I think there will be some kind of difference between the tadpoles.”
Who do you agree with more? Explain your answer in detail.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

13. Results
Compare the average measurements before and after the tadpoles were left overnight in each of the pools.
Which average body measurements changed?
What benefit does this have to the tadpole population?
No Predator Pool
Body Measurements
AVERAGE measurement BEFORE left overnight
AVERAGE measurement AFTER left overnight
Body Width
2.7 mm
Body Length
4.1 mm
Tail Muscle Width
0.63 mm
Total Length
11.5 mm
Color
Brown
Predator Pool
Body Measurements
AVERAGE measurement BEFORE left overnight
AVERAGE measurement AFTER left overnight
Body Width
2.7 mm
2.3 mm
Body Length
4.1 mm
Tail Muscle Width
0.63 mm
0.88 mm
Total Length
11.5 mm
Color
Brown
Predator Pool
Body Measurements
AVERAGE measurement BEFORE left overnight
AVERAGE measurement AFTER left overnight
Body Width
2.7 mm
2.3 mm
Body Length
4.1 mm
Tail Muscle Width
0.63 mm
0.88 mm
Total Length
11.5 mm
Color
Brown

14. No change Lower Higher Results:
Body Measurements
Change in population average in pools with no predators overnight
Change in population average in pools with predators overnight
Body Width
No change
Lower
Color
Tail Muscle Width
Higher
Total Length
Body Length
What benefit does this have to the tadpole population?
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

15. Differences that look small can be very important in survival.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

16. Rabbit species in Australia
A heat spell in Australia put a lot of stress on mammals, including rabbits. Many rabbits died.
How might rabbits that survive differ from rabbits that died during the heat wave?
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

17. Do you see any differences between this rabbit that survived and this rabbit that died?
What variations do you think contributed to the survival of the one rabbit and the death of the other?
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

18. Rabbit species in Australia
The ears of rabbits that survived were slightly longer, on average.
Large ears help rabbits get rid of heat from their bodies.
In a heat spell, longer ears help rabbits stay cooler. Rabbits with longer ears can often survive better.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

19. Differences that look small can be very important in survival.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

20. Lekking Sage Grouse
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

21. A lek is an area where birds gather during the breeding season for community courtship displays to attract mates
Males:
The steps of the display “Strut” are the same in every male
Occur at dawn over a 3 month period
Females:
Visit a lek for 2-3 days before mating
Females choose a male to mate with
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

22. Click on the link to see a sage grouse display
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

23. What differences do you see between the two males?
Female
Male
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

24. Did you notice a difference in the two males?
What was different about the male that the female picked?
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

25. What did the scientists find?
Males that attended more leks and had a higher display rate mated with more females
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

26. Differences that look small can be very important in survival and reproduction.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

27. Anoles
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

28. Anoles vary in their hind limb length
Anoles vary in their hind limb length. Most anoles leg length fall into the range of 14mm to 17mm
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

29.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

30. Does it matter whether the legs are 15 mm long versus 17 mm long?
Why might it matter?
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

31. Anoles with longer hind limbs are able to run faster on trees with wide branches. Anoles with shorter hind limbs are able to run faster on trees with narrow branches.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

32. So in an area with trees with wide branches, which kind of anole has an advantage?
A: Anoles with longer hind limbs have a small advantage. They can run faster from predators on the trees. Helps with survival.
And in an area with trees with narrow branches, which kind of anole has an advantage?
A. Anoles with shorter hind limbs have a small advantage. They can run faster from predators on the trees, helps with survival.
So in a wood with trees with wide branches, anoles with longer hind limbs have a small advantage. They run faster from predators on the trees. A small difference in limb length helps them survive better.
But in a wood with trees with narrow branches, anoles with shorter hind limbs have a small advantage. They run faster from predators on the trees. A small difference in limb length helps them survive better.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

33. Differences that look small can be very important in survival.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

34. Grasshoppers
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

35.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

36. Experimental Setup 8 cages, each with 15 grasshoppers
Scientists measured many traits of the grasshoppers, including:
Length
Weight
Leg Length, etc.
Then the scientists released three praying mantids (predators) into each cage overnight
They collected all the grasshoppers that survived and measured them again
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

37. Experimental Setup
- Cages with 15 Grasshoppers each
They measured all the traits of all the Grasshoppers.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

38. A single dragonfly larva (predator) was released into the 8 ponds.
Experimental Setup
- Cages with 15 Grasshoppers each
- Praying Mantis in cage
A single dragonfly larva (predator) was released into the 8 ponds.
They measured all the traits of all the Grasshoppers.
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

39. Cages overnight
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

40. Not all Grasshoppers survive
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

41. Individually Answer Question #1 in Packet
Individually, read and complete the following question.
1. Two students were thinking about the grasshopper study.
Eric said, “It’s clear. All the grasshoppers are just about the same in each cage. Just by chance, some grasshoppers will be lucky and survive, and others will be unlucky and get caught by the praying mantids. On average, the grasshoppers that survive will be the same as the grasshoppers that are eaten.”
Tara said, “I don’t agree. I think there will be some kind of difference between the grasshoppers.”
Who do you agree with more? Explain your answer in detail.
Share answers
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure

42. Variation
2. What variation(s) in traits might have been different between the grasshoppers that died and the grasshoppers that survived?

43. Closure How does variation affect survival?
How does variation affect reproduction?
I will be able to explain what a variation is and its affects on a species by discussion the idea of selection pressure