Characteristics of Life

Is the Flame Alive?

Biology Biology is the study of life. Study of all living and once living organisms

Characteristics of Living Things Living things are made up of cells Living things are based on a universal genetic code Living things grow and develop Living things respond to their environment Taken as a group, living things evolve. Living things obtain and use material and energy Living things maintain a stable internal environment Living things reproduce

All Living Things are Made of Cells The cell is the smallest unit capable of all life functions Some organisms have only one cell (unicellular) or can have many cells (multicellular).

Living Things are Based on a Universal Genetic Code All organisms store the information they need to live, grow, and reproduce in a molecule called DNA.

Living Things Grow and Develop A fertilized egg divides again and again. As these cells divide, they differentiate and perform different functions.

Living Things Respond to their Environment Organisms detect and respond to stimuli from their environment.

Taken as a Group, Living Things Evolve Organisms change to be better suited to the environment.

Living Things Obtain and use Material and Energy All organisms need to take in materials and energy to grow Combinations of chemical reactions through which organisms build up or break down materials is called metabolism. Catabolism – Break down/Release energy Anabolism – Build/Absorb Energy

Living Things Maintain a Stable Internal Environment All organisms have to keep their internal environment stable even when the external environment changes. This is called homeostasis.

Homeostatic Mechanisms Systems that maintain homeostasis by controlling Body Temperature Body fluid composition Blood Sugar Gas concentrations Blood Pressure

Body Temperature

Body Fluid Composition

ADH Anitidiuretic Prevents dilute (water filled) urine Signals for the reuptake water Thirsty – ADH is released Alcohol blocks ADH receptors

Blood Sugar

Fever An increased body temperature helps the immune system to work more swiftly. However, if your body is too hot for too long, the proteins that help your body to function will denature. Why do you feel cold when you have a fever? The body maintains a constant temperature of 98.6 F In order to raise the temperature of your body, the Hypothalamus tricks your body into thinking it’s cold. As a result, your body shivers and entices you to hide under blankets to get warm. Whenever, the fever breaks, the Hypothalamus tricks your body into thinking it’s warm. As a result, you throw off the blankets and sweat to cool your body down.

Respiratory Rate If there’s a build up of CO2 in the blood, it will turn very acidic. Chemoreceptors in the Aorta signal to the Medulla Oblongata to breathe faster

Living Things Reproduce Must pass on genetic information. Altruism? Most plants and animals engage in sexual reproduction. Cells from two parents unite to form the first cell of a new organism. Asexual reproduction is when a single organism creates identical offspring of itself.