Characteristics of Life

Characteristics of Life

All living things share some basic characteristics: 1. Organization 2. Movement 3. Made up of cells 4. Reproduce 5. Grow and / or develop 6. Obtain and use energy 7. Respond to the environment 8. Adapt through evolution

#1 Organization Life is organized on many structural levels

Check out this animation that gives you a sense of scale of some of the structures studied in biology! It s AWESOME!!!!

Atoms The smallest unit of matter Composed of: Protons Positive charge Located in the nucleus Neutrons Neutral charge Located in the nucleus Electrons Negative charge Locates in orbits around the nucleus Most important elements in biology are: Carbon Hydrogen Oxygen Nitrogen Phosphorus

Molecules Groupings of atoms bonded together Important bio-molecules: Proteins Lipids Nucleic acids Carbohydrates

Organelles Membrane bound subcellular structures that perform specific functions for a cell. Examples: Mitochondria Chloroplasts Nucleus Golgi

Cells The smallest unit defined as life

Tissues A group of cells having a similar structure working together to perform a specific function

Organs Groupings of tissues united to perform a specific function

Organisms Living things that have (or can develop) the ability to act or function independently.

Populations Localized groups of organisms belonging to the same species

Communities Populations of species living in the same area.

Ecosystems Energy processing systems of community interactions that include abiotic environmental factors such as soil and water.

Biomes Large scale ecosystems classified by predominant vegetation type and distinctive combinations of plants and animals.

Biosphere The sum of all of the planets biomes

Each level of biological organization exhibits emergent properties (click link) Ex. Capillaries transport blood (property not exhibited by individual endothelial cells).

#2 Movement All living organisms have internal movement; the ability to move substances from one part of their body to another. Some living organisms show external movement as well; the ability to move from place to place in a habitat.

#3: Composed of one or more cells

The cell theory 1.All known living things are made up of cells. 2.The cell is structural & functional unit of all living things. 3.All cells come from pre-existing cells by division (spontaneous generation does not occur).

Evidence for the Cell Theory Read this short summary of evidence for the cell theory.

Organisms can be unicellular or multicellular Unicellular: An organism consisting of a single cell that is capable of carrying out all of the functions of life Examples: bacteria, amoeba, yeast

Organisms can be unicellular or multicellular Multicellular An organism consisting of more than one cell working together to carry out all of the functions of life Examples: oak tree, caterpillar, salmon, mushroom

Cells in multicellular organisms differentiate (click link to read what this means!)

Cells are either prokaryotic or eukaryotic Prokaryotic All bacteria cells Lack membrane bound organelles Tend to be smaller in size than eukaryotic cells DNA not in nucleus (since they don t have one) and not coiled into chromosomes Eukaryotic Found in protists, plants, fungi and animals Contain membrane bound organelles DNA (found inside the nucleus) can coil around proteins to form chromosomes

Whether prokaryotic or eukaryotic, all cells share four common structures Cell membrane Cytoplasm DNA Ribosomes

#4: Reproduction Each organism arises through reproduction in which DNA instructions are transmitted from parents to offspring.

Reproduction is based on: A complex mechanism for copying DNA Passing the information encoded in DNA from parent to offspring via sexual or asexual reproduction

Sexual: Reproduction involves the fusion of a male and a female gamete (egg and sperm) Results in a new genome that is different than that of either parent. Example: flower pollination in plants

Asexual: Reproduction without the fusion of gametes Produces a clone of the original organism, and therefore does not increase genetic variation in the species as a whole. Example: binary fission in bacteria

#5: Grow and / or develop Growth means to get bigger in size

Development involves a change in the physical form or physiological make-up of an organism

#6 Obtain and use energy Living organisms need energy to grow, develop, repair damage, and reproduce

For most life forms The ultimate source of energy is the sun

Producers (AKA autotrophs) Organisms that trap solar energy by photosynthesis and use it to convert CO2 into a usable food source (glucose). Plants, blue-green algae

Consumers (AKA heterotrophs) Organisms that cannot synthesize their own food, and therefore must feed on other food sources found within the environment.

Detritovores Organisms that feed by ingesting dead organisms Crabs, earthworms and vultures

Saprotrophs (AKA decomposers) Organisms that secrete enzymes on dead organisms that cause decomposition, and then they absorb the resulting simple compounds into their bodies. So they do not ingest whole food, but rather, they absorb decomposed and digested food. Bacteria and fungi.

One reason organisms need energy is to maintain homeostasis A tendency for an organism to maintain a constant internal environment (i.e. temperature, salt concentration, and ph)

Organisms rely on their metabolism to maintain homeostasis Metabolism: The sum of all the chemical reactions in an organism by which molecules are combined together (ANABOLISM) or broken apart (CATABOLISM) in turn storing or releasing energy.

#7 Respond to the Environment Organisms react to stimuli in the environment: Light Temperature Odor Sound Gravity Heat Water Pressure Visual An example is a plant s leaves and stems growing toward light, or a person moving a hand from a hot surface.

#8 Adapt Through Evolution Adaptation - an inherited behavior or characteristic that enables an organism to survive & reproduce. Over time, adaptations are modified by natural selection.

Review your notes: Recite: Talk aloud! Review from memory what you have learned Using the left hand margin's key words and questions, talk through, or illustrate definitions, concepts, etc. Create your own examples Teach someone else (BTW, parents love to be taught biology by their kids!) Reflect: Think over! How does this relate to what you knew before? What would you still like to learn about this topic? Review the notes you took Schedule in your planner a reminder to study these Notes #1 at the key times for review: in 24 hours, 48 hours, one week and once a month until the end of the school year.