Suppose that the number of bird species is determined mainly by the number of vertical strata found in the environment. If so, in which of the following biomes would you find the greatest number of bird species? a. tropical rain forest b. savanna c. desert d. temperate broadleaf forest

Video transcript

Hi everyone. Let's look at our next question, considering that plants need sunlight, the right temperature, water and nutrients to grow. Which of the following bio MEMS will you expect to have the lowest net primary productivity. So we're looking for the fewest amount of plants growing in which bio. So I'm just gonna kind of make a little chart. So we can kind of think about each of these needs of plants and kind of evaluate for each by OEM to look at which one we would expect to have the lowest productivity in terms of plants. So we've got some we've got temperature, correct temperature, we've got water and we've got nutrients so soil nutrients there. So let's look at choice A choice A is rainforest well um sunlight or generally that's a positive that they're in equatorial regions. So um get plenty of sunlight. Now there is competition in terms of the tall trees and things on the forest floor, but in terms of the location on the earth, plenty of sunlight in general. Um the right temperature. Yes, rainforests again, generally warm, good growing temperature, water definitely um plenty of water in the rainforest and nutrients also pretty decent there. So we're gonna go ahead and eliminate choice a rainforest because we can pretty definitely bet that will not have the lowest amount of productivity. And of course when we think about a rainforest we think of it full of many many plants. So we almost didn't even have to write that. Um If you just think of a rainforest you could have on a test eliminated that right away. Choice B is tundra. So maybe a little trickier to think about. Um We've got sunlight. Um tundras, tundras in the arctic region. So sunlight is going to be probably a negative here. Long periods of darkness. Uh temperature we would say is a negative um Lots of very cold, extreme cold temperatures. Although you do have um the short summers where you've got favorable temperatures there. So then we'll look at water. Um water. I'm kind of gonna give it neither a plus or minus tundras are rather dry um In general, but not say it's dry as a desert. So just kind of leave that blank for now is neither positive nor negative and then nutrients are the one positive. They have plenty of soil nutrients in the tundra. So let's look down the choice. See savannah. Well, savannah, we think of those grassy plains, like in africa plenty of sunlight, their favorable temperature. Water. I'll leave that blank. They have um many very dry season. They have a very dry season, but they also have a rainy season. So we'll kind of leave that neutral and the nutrients um probably a neutral as well. It's not um super nutritious soil, but there are some there you think of it with lots of grass and a few trees. So we'll leave that kind of blank as well. And finally choice. The the desert. Well desert, we got plenty of sunlight but temperature definitely a negative, very high heat. Very difficult for plants to grow in that intense heat and water. Of course, we're going to say double negative, so little water and the heat of course, contributes to that. The very little precipitation and what water there is evaporates very quickly and nutrients, the sandy soil of the desert, very few nutrients. So again, maybe a double negative on that. So looking at this chart, overall, we do have maybe a close competition between the tundra and the desert, but the extreme high heat and dryness of the desert, plus lack of nutrients in the soil really would lead us to expect that the desert would be our area of lowest primary productivity when it comes to plants. And we'll go ahead and eliminate tundra and savannah. So, looking at this again, considering the needs of plants, the bio that we would expect at the lowest net primary productivity is choice de desert. Thanks for watching. We'll see you in the next video