Mice homozygous for a null allele of dhh exhibit defective spermatogenesis

TLS Online TPP Program

#Id: 7977

#Unit 10. Ecological Principles

THERMAL PROPERTIES OF WATER

Pure water becomes a solid below 0°C and becomes a gas above 100°C at sea level.

When water contains dissolved compounds, such as salts, its freezing temperature drops below 0°C.

Dissolved compounds also raise the boiling point of water above 100°C. 

TLS Online TPP Program

#Id: 7978

#Unit 10. Ecological Principles

Thermal stratification

TLS Online TPP Program

#Id: 7979

#Unit 10. Ecological Principles

Water achieves its highest density—that is, its molecules are the most packed together—at 4°C.

TLS Online TPP Program

#Id: 7980

#Unit 10. Ecological Principles

Organisms that are denser than their surrounding water, a variety of adaptations can either reduce an organism’s density or retard its rate of sinking.

TLS Online TPP Program

#Id: 7981

#Unit 10. Ecological Principles

Many fish species have a gas-filled swim bladder that can adjust in size to make the density of the fish’s body equal to that of the surrounding water.

TLS Online TPP Program

#Id: 7982

#Unit 10. Ecological Principles

Adaptation to water viscosity

Some small aquatic organisms exploit the high viscosity of water by evolving large appendages

Streamlined shapes that reduce the drag caused by the high viscosity of water