For what kind of external environment is a saltwater fish adapted? (1 point)
• hypotonic environment
• hypertonic environment
• osmotonic environment
• isotonic environment
A saltwater fish is adapted to a hypertonic environment.
A saltwater fish is adapted for a hypertonic environment.
To determine for what kind of external environment a saltwater fish is adapted, we need to understand the concepts of osmosis and tonicity.
Osmosis is the movement of water molecules across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration. Tonicity refers to the relative concentration of solutes in two fluids separated by a membrane.
In this case, a saltwater fish lives in a highly saline environment. The water in the ocean has a higher concentration of salts compared to the internal body fluids of the fish. Therefore, the fish needs to adapt to maintain proper water and salt balance.
Considering the given options:
1. Hypotonic environment: A hypotonic environment has a lower concentration of solutes compared to the internal fluids of the fish. In this case, water would tend to move into the fish's body, causing it to gain water and potentially disrupt its osmotic balance. Therefore, a saltwater fish is not adapted to a hypotonic environment.
2. Hypertonic environment: A hypertonic environment has a higher concentration of solutes compared to the internal fluids of the fish. A saltwater fish is adapted to live in a hypertonic environment since the external ocean water has a higher concentration of salts than the fish's internal fluids. This allows the fish to maintain its osmotic balance and prevent excess water loss.
3. Osmotonic environment: The term "osmotonic" is not commonly used in biology. It is likely a combination of osmosis and tonic, referring to the concept of tonicity. Since the options appear to be in reference to tonicity, we can exclude this option.
4. Isotonic environment: An isotonic environment refers to two fluids having the same concentration of solutes. In this case, the fish would not experience a net movement of water, but the ocean water is not isotonic to the fish's internal fluids. Hence, a saltwater fish is not adapted to an isotonic environment.
Based on the explanations above, we can conclude that a saltwater fish is adapted to a hypertonic environment.