Lazy Pandas

Lazy Pandas

From buffalo case studies

Reminder: Proximate vs Ultimate

Open Ended

What is your best bet for the ultimate cause for WHY a panda only eats bamboo?

Skip this small group question, focus on the main question.

Response on next slide

Multiple Choice

What type of digestive tract might you expect to see in a giant panda and why?

• A.I agree with the hypothesis. I expect to see an herbivore type of digestive tract, because herbivory requires a long, complex digestive tract.

• A.I disagree with the hypothesis. I expect to see a carnivore type of digestive tract, because the common ancestor of giant pandas was a carnivore and that places an evolutionary constraint on the digestive tract.

We did this slide in a prior lesson, go fast

Answer on next slide.

Open Ended

Can you propose an alternative hypothesis?

Answer on next slide

Poll

Giant pandas have low energy demands relative to other bears.

• I agree with the hypothesis. A large mammal would not be able to survive on such a low quality diet if it had similar energy requirements as other mammals of the same size.

• A.I disagree with the hypothesis. Energy expenditure is based on body size – big animals have big energy requirements.

Multiple Choice

Hypothesis 2: Giant pandas have low energy demands relative to other bears or mammals

Test: measure the metabolic rate of pandas by measuring their daily energy expenditure (DEE).

Does the data support the hypothesis?

• No, giant pandas are big animals, but their DEE is low compared to other mammals of the same size.

• Yes, giant pandas are big animals, but their DEE is low compared to other mammals of the same size.

Open Ended

List one-way pandas can decrease their energy expenditure?

Multiple Choice

What prediction arises from this hypothesis?

• Giant panda will be less active than other bears, thus allowing them to use fewer calories per day.

• Giant panda will be more active than other bears because they need to find more food to make up for the lack of calories in bamboo.

Answer on next slide

Poll

Does the data support the hypothesis?

• yes

• no

Let's fast forward...

• There were originally 49 slides in this presentation. I am going to cut several out by summarizing the ideas

• We know that panda MUST use minimal energy to survive. But HOW????

Poll

To use reduce energy use, what would you expect from a pandas fur?

• very thick to be highly insulating

• very thin to be easier to create

Poll

Some organs require a lot of energy to use and maintain. What would you expect from a panda?

• large brain in ensure best decisions made each day

• small brain to reduce energy and proteins needed each day

Poll

Some thyroid hormones regulate metabolism. What would you expect to see in pandas?

• High thyroid hormones to allow for energy to find food all day

• Medium thyroid hormones to use just enough energy to survive

• Low hormones to resemble a hibernating bear