lecture 15

How organisms get their energy and nutrients and how they maintain their physical condition Physiologists focus on the internal functioning of organisms.

How organisms deal with their environment and how the environment limits where they live Ecologists examine the interactions between organisms and their surroundings.

How organisms’ bodies function (physiology) helps them survive (ecology) This field integrates physiological processes with ecological contexts.

Similar environments lead to similar adaptations This phenomenon occurs when unrelated species evolve similar traits due to similar environmental pressures.

• their temperature changes with the environment • they cant regulate heat internally • requires less energy Poikilotherms cannot regulate heat internally, while homeotherms maintain a constant internal temperature.

• as sphere gets bigger, SA:V gets smaller • high SA:V (smaller bodies) can get rid of heat better (good for warm weather) • low SA:V (larger bodies) gets rid of heat slower (good for colder weather) • more round an organism is, the better it retains heat This ratio affects heat loss or gain in organisms.

• homeotherms tends to have smaller body parts (ears) in colder places • having smaller body parts makes them more spherical minimizing SA:V Smaller body parts minimize surface area to volume ratio, aiding in heat retention.

• When veins and arteries are near each other, it conserves heat which is better for colder climates • when veins and arteries are farther from eachother, it sheds out more heat so its better for warmer climates This adaptation is beneficial in colder climates.

Trade-offs and constraints Being good at one aspect often comes at a cost to another, and evolution works with existing traits.

• animals at higher latitude (colder) can withstand colder temperature than the organisms at lower latitude (warmer) and vice versa • animals at higher latitude can tolerate a wider range of seasons

• keeps their body temperature constant • they need more energy

• helps organisms cool down

• movement of blood flow around the body to either let heat out or to conserve heat

• fur • fat • feather

• Radiation - heat transfer by electromagnetic radiation eg: Warms up by sitting next to fire • Conduction - transfer by direct contact eg: Warms up by touching something hot • Convection - heat moving by air or water eg: Wind cooling your skin • Evaporation - cooling from wet surfaces eg: Sweating • redistribution - our body moving heat around the body

• keeps conditions stable • the internal environment will be stable (their body) even if the external environment is changing