Marine Biology Homework Help?

1.Typical marine fishes

a.tend to gain water by osmosis since their internal salt concentration is higher than that of seawater.

b.tend to lose water by osmosis since their internal salt concentration is lower than that of seawater.

c.do not drink seawater since they need to conserve as much water as possible.

d.produce a large volume of urine since they need to conserve as much water as possible.

e.taste great grilled with lemon and dill.

2.A marine biologist wishes to test the hypothesis that heavy grazing by snails causes the alga Ulva to stay short rather than grow upright. Which of the following variables could be manipulated successfully at the seashore to test this hypothesis?

a.add nutrients to the nearby ocean waters to see if the algae grow taller.

b.put a small cage around the algae to keep snails from eating them and then see if the protected algae are taller than unprotected ones.

c.change the light intensity to see if this causes the algae to stay short.

d.redirect ocean waves to see if wave shock causes the algae to stay short.

e.plant tall Ulva and see if they get grazed.

Marine Biology Homework Help?windows update

1 - b.tend to lose water by osmosis since their internal salt concentration is lower than that of seawater.

(You'd have to know that the salt concentration in seawater is higher than in the bodies of the fish - probably somewhere in your notes or text! - and salt doesn't easily pass through the cell membrane, but water does. To equalize the salt concentration on both sides of the cell membrane, water has to move out of the cell to dilute the seawater they take in.) I'd agree with "e" as well!

2 - b.put a small cage around the algae to keep snails from eating them and then see if the protected algae are taller than unprotected ones. (This is the only one which really tests the hypothesis, although it might produce a false result if fish were what was eating the algae.)