Fluid Balance - Aquatic Organisms: Osmoconformers

Question 1

What are the three types of solutions?

Answer 1

1. Isotonic.
2. Hypertonic.
3. Hypotonic.

Question 2

What is an isotonic solution?

Answer 2

Two solutions have the same concentration of dissolved ions. There is no net movement of water. Water may move in and out via diffusion.

Question 3

What is a hypertonic solution?

Answer 3

When the surroundings are more concentrated than the environment. Water will diffuse out the cell by osmosis to dilute the outside concentration.

Question 4

What is a hypotonic solution?

Answer 4

When the surroundings are less concentrated than cellular contents. Water will diffuse into the cell via osmosis making the cell contents less concentrated than its surroundings.

Question 5

What are osmoconformers?

Answer 5

Maintain ion and water levels to be isotonic with surroundings. Body fluid composition varies with that of the water surrounding them. Internal species can tolerate large variations.

Question 6

What are examples of osmoconformers?

Answer 6

Marine invertebrates such as -
- starfish.
- jellyfish.
- worms.

Question 7

Describe marine organisms.

Answer 7

Sea water has a high level of dissolved ions in it. It is hypertonic to most organisms. Water moves out of organisms by osmosis and ions move into organisms by diffusion.

Question 8

Describe marine bony fish and their adaptations that classify them as osmoconformers.

Answer 8

Fish are hypertonic. They lose water by osmosis and gain ions by diffusion.
1. They drink large amounts of salt water.
2. They excrete excess salt through secretory glands in the gills through active transport.
3. They have very few nephrons and so produce small amounts of highly concentrated urine.

Question 9

Describe cartilaginous fish and their adaptations that classify them as osmoconformers.

Answer 9

1. Kidneys reabsorb and maintain high ura levels and are slightly hypertonic.
2. They will excrete a large volume of water to dilute urine.
3. They excrete salt from the salt glands in the rectum.

Question 10

Describe mammals and their adaptations that classify them as osmoconformers.

Answer 10

1. Their kidneys produce urine high in both urea and salt.
2. They survive on metabolic water and food sources are high in water.
3. They experience highly efficient reabsorption of water from the rectum.

Question 11

Describe marine birds and their adaptations that classify them as osmoconformers.

Answer 11

1. They ingest high levels of salts in food and water.
2. Excess salt is excreted through the nasal gland.
3. They use counter-current blood flow to remove large amounts of salt.
4. The glands secrete a solution with a higher salt concentration than seawater.

Question 12

What are the three disadvantages of marine organisms?

Answer 12

1. Lower water concentration in cells than in surrounding cells.
2. Water moves out of cells.
3. Ions move into cells.

Question 13

What are four adaptations of marine organisms?

Answer 13

1. Retain high levels of urea.
2. Small amounts of highly concentrated urine.
3. Fewer nephrons.
4. Surive on metabolic water by highly efficient reabsorption of water from the rectum.