Biology Forums - Study Force

I desperately need help and i got a really bad grade on this test. For corrections i have to explain whythe answer is right. will someone explain why these answers are right.

1) which of the following statements about light in aquatic enviroments are correct?
right answer:water selectively reflects and absorbs certain wavelengths of light & light intensity is an important abiotic factor limiting the distribution of photosynthetic organisms.

2) In an altitudinal gradient, all of the following would change in the same way as in a graident except
right answer: day length

3) Which of the following causes Earth's seasons?
right answer: the tilt of earth's axis
4) As climate changes because of global warming, spieces' ranges in the northern hemisphere may move northward. tHE trees that are most likely to avoid extinction in sich an enviroment are those that
right answer: have wind- dispersed seeds & have animal-dispersed seeds

Hey flower555,

Water selectively reflects and absorbs certain wavelengths of light & light intensity is an important abiotic factor limiting the distribution of photosynthetic organisms.

Imagine if the water was murky or muddy. The particles in the water will reflect the light from sun, thereby preventing it from penetrating deep into the water. If the light intensity is very low (such as on a cloudy day or when the water is heavily polluted), the primary producers won't be able to undergo photosynthesis - the process that essentially produces oxygen and carbohydrates (sugars) for the primary consumers to eat and grow. 

In an altitudinal gradient, all of the following would change in the same way as in a graident except
right answer: day length

Altitude has very little to do with how much sunlight a certain area receives. Rather it is a change in latitude which ultimately effects how much light the area receives. For instance, during the winter months, the northern hemisphere receives barely any light even though they have huge mountains which exceed very high altitudes (heights). If you go were to travel down south during this same season (lower latitude), you'll find that there is plenty more sunshine. Therefore, the height of a terrain doesn't really effect sunlight.

Which of the following causes Earth's seasons?
right answer: the tilt of earth's axis

The earth is tilted at a 23.5 degree angle. So, rather than revolving around the sun like this  |  , it is actually positioned like this \ . If this is the sun O and this is earth \, than the land at the tip that is closest to the sun will be experiencing hotter weather (summer or fall).

As climate changes because of global warming, spieces' ranges in the northern hemisphere may move northward. tHE trees that are most likely to avoid extinction in sich an enviroment are those that
right answer: have wind- dispersed seeds & have animal-dispersed seeds

As you can tell, trees are not mobile species. So they have seeds which they produce that can be dispersed by either the wind or animals. They will be least effected because they regularly depend on the wind and animals to allow for their future survival. Global warming will not effect the wind patterns or migration patterns and even if they do, the animals are moving in that direction anyways so the seeds will tag along and sprout wherever the animals go or the wind takes them.