An ostrich’s eye is bigger than its brain.

Biology is the study of living things.

Bio: LivingAbio: Non-living

Scientific Method

How do scientists go about solving problems?

They have developed a guide or approach to solving problems that works. It is called the scientific method and has 7 parts.

Scientific Method

1. Identify and state the problem.

2. Do some research. Gather information.

3. State a hypothesis. A hypothesis is a suggestion for a solution to the problem.

Scientific Method

4. Design an experiment.- A good experiment tests only one

variable. All other variables remain the same.- A variable is anything that can affect the

results of an experiment. Ex. You want to know which fertilizer is best. The only thing you can change is the fertilizer. You have to grow plants in the same soil, at the same temperature with the same amount of sunlight and water.

Scientific method

5. Make observations and record data.- Data are observations made during

experiments- Data could be measurements,

numbers,text.

6. Organize and analyze the data.- Graphs, charts, tables, diagrams,

paragraphs - Once data is organized, it can be

analyzed and studied to see if they “support the hypothesis”.

7. State a conclusion.A conclusion is a summary that explains the observations and describes how the data relates to the problem. It also states

if the data supported the hypothesis.

Were you right?

Theories about living things

• Aristotle – Developed the theory of spontaneous generation (abiogenesis) which states that:living things come from non-living things.ie. Flies come from dead animals

Frogs come from mudMice come from dirty rags

Fransesco Redi

In 1660, disproved the theory of Spontaneous Generation

(Control: You know what will happen Always used as a comparison)

Redi’s Experiment

John Needham

• Mid 1700s

• British

• Needham tried to prove that spontaneous generation could occur in the right circumstances. (He disagreed with Redi.)

John Needham’s Experiment

Lazzaro Spallanzani

• Italian

• Felt that Redi was right and that Needham’s experiment had failed because he did not boil the broth long enough or did not have a tight enough stopper.

• He boiled 2 containers of gravy, sealed one and left the other open.

Spallanzani• After a few days:

- the open container was teeming with microorganisms and was cloudy.- the sealed container remained free of organisms.

• Conclusion:The broth did not produce living things. The microorganisms in the open container were the offspring of microorganisms that had entered through the air.

Louis Pasteur

• 1864

• French

• Designed a flask that would disprove spontaneous generation once and for all.

Pasteur

Life is Cellular

• Without the instruments that made them visible, cells remained out of sight and unknown.

• The microscope changed all that!

• http://www.youtube.com/watch?v=h85_U9OJFQ0

MicroscopeMid-1600s:- Anton van Leeuwenhoek HollandSingle lens microscope to examine pond water

- Robert Hooke England compound microscope (2 lenses) Examined a thin slice of cork.

Cell theory

• Soon different observations about cells were being made by scientists all over.

• In the mid-1800s these observations were combined to form the cell theory, a fundamental concept of biology.

Cell theory states:

All living things are composed of cells.

Cells are the basic units of structure and function in all living things.

New cells are produced from existing cells.

The two main types of cells are:

1. Prokaryotic cells

2. Eukaryotic cells

Prokaryotic CellsCells that lack a “membrane-bound nucleus” are called prokaryotes (from the Greek meaning before nuclei).

Prokaryotic cells are different from eukaryotic cells. They don't have a membrane-bound nucleus and instead of having chromosomal DNA, their genetic information is in a circular loop called a plasmid.

Eukaryotic cells

Eukaryotic cells (from the Greek meaning truly nuclear) comprise all of the life kingdoms except bacteria. They have a membrane-bound nucleus.

DNA (deoxyribonucleic acid) is stored in the nucleus.