Unit 1: What is Biology

I. What is Biology? A.Biology – study of life, of all living things 1.Many branches: biochemistry, cell biology, genetics, evolutionary theory, microbiology, botany, zoology, et.

B. Six (6) Major Themes in Biology 1.Cell Structure & Function a)Unicellular – organisms made of one cell b)Multicelluar – organisms made of more than one cell 2.Stability & Homeostasis a)Homeostasis – a level or stable internal environment in cells/living things

3.Reproduction & Inheritance a)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.Evolution a)Evolution – how organisms change and come to exist b)Natural Selection – “survival of the fittest”; drives evolution

5.Interdependence of Organisms 6.Matter, Energy, & Organization a)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 Life 1.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. Biogenesis A.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 GroupExperimental Group - Placed raw meat in an- placed meat in a jar open jarcovered with netting - In a few weeks, maggots- in a few weeks, maggots were on the meatwere on the netting - Flies layed eggs on meat,- flies could smell meat, maggots are fly larvabut only lay eggs on netting

3 rd Experiment by Redi -Placed meat in a sealed jar -Maggots never appeared -Flies could not smell the meat

Redi’s Experiment

C. Lazzaro Spallanzani – 1768, microscopes have been invented & microorganisms are known to exist; tests the spontaneous generation of microorganisms. Control GroupExperimental 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

Spallanzani’s Experiment

D. Louis Pasteur – 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.

F.Scientific Theories – highly tested, generally accepted principle that explains a vast number of observations and experimental data –Hypothesis = specific, testable prediction for a limited set of conditions –Theory = general explanation for a broad range of data

IV. Units of Measurements A.International System of Units (SI units) 1.Used by all scientists 2.Uses multiples of ten (10)

B. SI bases units – pg. 1058, 1059 QuantityUnitAbbrevation Lengthmeterm Masskilogramkg Volumecubic meterm3 Timeseconds TemperaturekelvinK Densitygram per cubic centimeterg/cm3 Amount of substancemolemol

C. SI Prefixes - pg. 1058, 1059 PrefixAbbreviationExponent Mega-M10 6 Kilo-k10 3 Hecto-h10 2 Deka-da10 1 Base unit 10 Deci-d10 -1 Centi-c10 -2 Milli-m10 -3 Micro-µ10 -6