Fall2011_Lab10

=Lab 10 - Foraging Behavior=

Quiz: Quiz this week will be over cardiovascular system and the experiments we conducted.

Lab:
We'll conduct a simulation of foraging behavior using beans (simulated food) in a bucket of rice (simulated environment). Each group will take on roles of different foragers, and in a game-like setting, you will be timed to see how effectively you can forage for food. We will explore the effect of different strategies on how much food can be gathered (dependent and independent variables, here), but because this is a game, all players will eventually run out of food to find in the bucket of rice. Factors we will explore include the nutrient content of food, the toxicity of food, and the ease at which certain foods are gathered.

//**Download the lab, print it off, and read thorough it**// before you come to lab. It's on the course content section on blackboard.

Mini-Lecture on Foraging:
- We've gone over lots of physiology concepts in the past labs, now we can focus on the overall behavior of the organism, and in this lab we'll look at foraging behavior, or: how to get food. - Think about what strategies different animals use to get food. There are animals that eat other animals, and there are animals that eat plants, and there are plants that "eat" sunlight. These are all kinds of foraging. Think about a competition for berries among different forest animals. How do these species compete for the best berries? Maybe eating the 2nd best berry is easier, because there is less competition for food, and overall there are enough 2nd-rate berries to get the same amount of nutrients. There is an idea in biology that two species will never compete head-to-head, so to speak, over the same resource. So if two species are interested in the #1 berry, perhaps they will forage in different areas, or they will forage at different times of the season. These strategies allow both species to live off of the same berry. If they didn't split up the resources, then they would compete head-to-head and one species would go extinct, because the more efficient forager would take all the food and the other species could not gather enough food to reproduce, and then that species would either switch to another food source or go exinct. - When we did our simulation, we looked at how long an animal lives (how many rounds you survived). If the animal can't find food, it "dies". If all of the individuals in a species die, then the species will go extinct. Also, the species may be a specialist or a generalist. A specialist species has special physiological adaptation (better digestion, quicker foraging ability, etc.) that allows that species to gain more nutrition or energy from certain food types. For example, the koala bear can only eat eucalyptas leaves, and these leaves are slightly poisonous to other mammals. How would this allow the koala to live longer? Would being a specialist ever be a bad thing? What kind of situations would make it good or bad to be a specialist? Likewise, in what situations would it be helpful to be a generalist? In what situations would it be bad to be a generalist? - Imagine some real-world situations of generalist or specialist, and imagine what would happen if they were competing for the same food type. What if there was only one food type in the world: would it be better to be a specialist or a generalist? What if there were equal amounts of multiple food types? Which would be a better dietary strategy for that species? - Evolutionary adaptations allow some species to have an advantage in foraging. If the cheetah species has adapted to run faster than other carnivores, cheetahs can catch some prey that the slow carnivores cannot catch. So this adaptation helps cheetahs not go extinct. In another example, koalas can eat the normally poisonous eucalyptas leaves, but they are so specialized in their physiology, they cannot eat any other types of plants. This adaptation is a physiological change in the species, that is specialized for a certain food type. While this is an adaptation that lets them eat leaves that other mammals can't eat, there is a physiological trade-off with other foraging processes, where the koala loses the ability to to eat other plants. - So, if there are only a few species that specialize in certain foods, this reduces competition for those particular food sources, which improves their chances of finding food. But if the food source depletes, the specialist cannot switch to another food source, and so competition for this food actually increases. - What parts of the lab relate to these different situations? Did you see parts of the game where there was competition? What dietary strategies (generalist or specialist) did best? Normally, dietary specialists do not have adaptations and specialists have an adaptation (immunity to poison, increased foraging efficientcy, etc.). Imagine that generalists cannot have any adaptations, and only specialists can possibly have adaptations. This is more like the real world, where the koala bear has a adaptation for eucalyptas leaves, but it cannot generalize for any plant type. If this is the case, when would it be good to be a specialists and when would it be good to be a generalist?