Lecture Notes-02 Biology 1004
North Arkansas College
Topic: Characteristics Common to all Living Species
Ability to Reproduce - Types
- Asexual - Single cell organisms (bacteria) - binary fission. Body cells of animals/plants via mitosis.
- Sexual - Sex cells of animal and others.
- Composed of Cells - Cell Theory (Robert Hooke). Viruses are considered non-living because they are non-cellular.
- Maintain Homeostasis - Regulate internal environment (inside cell); uses membranes to control homeostasis.
- Source of Energy - Drives chemical reactions to carry out metabolic events. Energy is produced as ATP (adenosine triphosphate). Each molecule of ATP contains 6,000-12,000 calories. One molecule of glucose produces a net of 36 ATP. The body stores very little ATP (<116), but uses 100 lbs (comes from food and stored fat).
- Organizational Levels - atoms - elements - molecules - cells - tissue - organs - intact organism.
- Response to a Stimulus - Physical, chemical, plants respond to light, animals respond to pheromones (chemical molecules). In humans, light stimulates or reacts with retinal cells of eye to produce chemical reaction which produces nerve impulses allowing us to see. The Venus Fly Trap (and other plants that consume meat) found in South Carolina - soil contains nitrogen (which is a major requirement for proteins and amino acids that make up those proteins) convert bugs and other species to nitrogen which allows them to make nutrients.
- Locomotion/Movement - All species demonstrate some type of movement, but not necessarily locomotion.
Adaptation - Change to meet a changing environment. These changes occur as:
- Physiological
- Structural
- Behavioral
- Combinations
Most animals exhibit an obvious locomotion - run, swim, wiggle, etc.
- Plant movement is subtler. Movement is in response to light (phototaxis) or cytoplasmic streaming.
- Many living species and their cells move via cilia or flagella - protozoa, bacteria, etc.
- Some species such as corals, sponges and oysters have a free-swimming larval stage but become attached during adult stage - Sessile.
