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 OrganizationLife 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 sub-

cellular 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.

A complex

mechanism for

copying DNA

Passing the

information encoded

in DNA from parent to

offspring via sexual or

asexual reproduction

Reproduction is based on:

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.