I. What is Biology?
A. Biology – study of life, of all living things1. Many branches: biochemistry, cell biology,
genetics, evolutionary theory, microbiology, botany, zoology, et.
B. Six (6) Major Themes in Biology1. Cell Structure & Function
a) Unicellular – organisms made of one cell
b) Multicelluar – organisms made of more than one cell
2. Stability & Homeostasisa) Homeostasis – a level or stable internal
environment in cells/living things
3. Reproduction & Inheritancea) Sexual Reproduction – DNA from 2 parts or 2
organisms is combined
b) Asexual Reproduction – DNA is not combined, rather an organism copies its DNA and splits
4. Evolutiona) Evolution – how organisms change and come to
exist
b) Natural Selection – “survival of the fittest”; drives evolution
5. Interdependence of Organisms
6. Matter, Energy, & Organizationa) Organisms obtain, use, & transfer energy &
matter
b) Autotrophs – organisms that can make their own food to obtain energy
c) Heterotrophs – orgnanisms that cannot make their own food, but must take it in for energy
C. Characteristics of Life1. Made of units called cells.
• Prokaryote Cell – cell that lacks a true nucleus and true organelles
• Eukaryote Cell – cell that has a true nucleus and true organelles
2. Reproduce
3. Based on a universal genetic code
4. Grow & develop
5. Obtain and use materials, and energy• Metabolism (Energy use) – sum of all
chemical reactions in an organism
6. Respond to external environment
7. Homeostasis – maintain a stable internal environment
8. As a group, living things change over time
FSGPT: Discuss examples of sexual & asexual reproduction. Give an example of a prokaryote and a eukaryote
II. Spontaneous Generation vs. BiogenesisA. Spontaneous Generation – early theory
that nonliving material could give rise to living organisms
B. Francesco Redi - In 1668, tested the theory of spontaneous generation, specifically that maggots come from rotting meat.
Control Group Experimental Group
- Placed raw meat in an - placed meat in a jar
open jar covered with netting
- In a few weeks, maggots - in a few weeks, maggots
were on the meat were on the netting
- Flies layed eggs on meat, - flies could smell meat,
maggots are fly larva but only lay eggs on netting
3rd Experiment by Redi- Placed meat in a sealed jar- Maggots never appeared- Flies could not smell the meat
C. Lazzaro Spallanzani – 1768, microscopes have been invented & microorganisms are known to exist; tests the spontaneous generation of microorganisms.
Control Group Experimental Group- Boiled broth to sterilize - boiled broth- Left flask open to air - sealed flask immediately- in several days, broth - in several days, broth
remains
was cloudy clear
D. Louis Pasteur – 18621. Many refused to give up their belief in
spontaneous generation. They argued that life required a “vital force”, and that Spallanzani killed this force and prevented it from entering by sealing the flask.
2. Pasteur completely disproved spontaneous generation and the idea of a “vital force”.
Pasteur cont.3. Pasteur boiled broth in a flask with a curved
neck. This allowed him to sterilize the broth and leave in open for the “vital force”. After 1 year, the broth remained clear and sterile.
FSGPT – Discuss and write down similarities and differences between the three scientists experiments.
E. Biogenesis – current, accepted theory that living organisms can only arise from preexisting living organisms.
III. Scientific Method
Steps:
A.Observing & Asking Questions
1. Observation – act of noting or perceiving objects or events by using the senses
B. Formulating a Hypothesis
1. Hypothesis – possible explanation that can be tested by observation or experimentation.
C. Perform an Experiment
1. Experiment – carried out under controlled conditions to test a hypothesis.
A. Control Group – group used as a comparison; results are known
B. Experimental Group – identical to control group except for one factor, making the outcome unknown.
i. Independent Variable – the factor that is different in the experimental group
ii. Dependent Variable – During the experiment, this is what is being observed or measured
2. Example: FSGPT
Hypothesis – adding food coloring to a white flower’s water will change the flower’s color
Control Group -
Experimental Group -
Independent Variable -
Dependent Variable -
D. Analyzing Results – complete calculations, plot data, summarize observations, etc.
E. Draw Conclusions & Verify Results 1. Draw conclusions that explain experimental
results.
2. Verify conclusions by repeating experiments & checking other scientists results.
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