Fundamentals of Biology

Chapter 4

Levels of Organization

• Atom Level

• Tissue Level

• Ecosystem Level

• Molecule Level

• Individual Level

• Organelle Level

• Organ System Level

• Cell Level

• Community Level

• Population Level

• Organ Level

• Atom Level

• Molecule Level

• Organelle Level

• Cell Level

• Tissue Level

• Organ Level

• Organ System Level

• Individual Level

• Population Level

• Community Level

• Ecosystem Level

MoleculeCombinations of atoms

that are bonded together

AtomThe fundamental unit of

all matter

Organelle A subcellular membrane-

bound compartment

Cell

Tissue

Organ

The basic unit of life

Group of similar cells that

perform a common function

Two or more different tissues

that perform a common

function

PopulationAll individuals of the

same species that

occupy a given area

Organ

System

Individual

Group of related organs that

have a common function

A single organism

Community

Ecosystem

All the species in an

ecosystem that can

interact

A community and its

physical environment

The Ingredients of Life• Elements- substances composed of only one type of atom.

– 94 naturally occurring.

– Carbon, Nitrogen, Hydrogen, and Oxygen account for 90% of the elements in living things.

The Building Blocks

Cells and

Organelles

Eukaryotic vs. Prokaryotic Cells

Feature Eukaryotic ProkaryoticOrganisms Animals, plants Bacteria, Archaea

Size 10-100 µm 1-10 µm

Organelles Yes No

DNA form Coiled, linear Circular

DNA location Nucleus Cytoplasm

Internal membranes Yes No

Cytoskeleton Yes No

Robert Hooke (1635-1703)

Cell Theory

• CELL THEORY- proposed in 1839 by Schleiden

and Schwann.

1. All living things are composed of cells.

2. The cell is the basic unit of life.

3. New cells arise only from preexisting cells.

4. Cells contain hereditary information which is passed

from cell to cell during cell division.

5. All cells are similar in chemical composition.

6. All of the energy flow of life occurs within cells.

Invention of the Microscope

• Invented circa 1595 AD by

Zacharias Janssen (1580-

1638), a spectacle maker

from Holland.

4 Types of Microscopes Used to Study Cells

• Dissecting microscope- 4-50X.– Light is passed through or reflected on a specimen.

– Focus with a set of glass lenses.

• Compound light microscope- 1,000X.– Light is passed through a specimen.

– Focus with a set of glass lenses.

• Transmission electron microscope- 50,000X.– Electrons are passed through a specimen.

– Focus with a set of magnetic lenses.

• Scanning electron microscope- 10,000X.– Electrons are scanned over the surface of a specimen that has

been coated with a metal.

– No Focus, produces a three-dimensional image collected from electrons that are emitted from the metal.

Dissecting Microscope

Diffusion

• Diffusion- the

spontaneous tendency of

a substance (solute or

solvent) to move from a

more concentrated to a

less concentrated area.

– T or F. Diffusion results in

the uniform distribution of a

substance.

Osmosis

• Osmosis- the diffusion of water through a selectively permeable membrane from a region of higher concentration to a region of lower concentration.

When referring to two solutions that are separated

by a selectively permeable membrane:

• Isotonic solutions have the same

concentration of solute as the cell.

• Hypotonic solutions have lower solute

concentrations than the cell.

• Hypertonic solutions have higher solute

concentration than the cell.

3 Domains and 6 Kingdoms

Classifying Living Things