What is Biology? Bio. 100 Tri-County Tec. College Pendleton, S. C.

What is Biology?

Bio. 100Tri-County Tec. CollegePendleton, S. C.

Biology

The Science of LifeBest defined as the “scientific study of lifeTwo critical important questions that divide our society: (1) When does life begin, and (2) When does life end?

Characteristics of Life

Living things can and do:MetabolizeMaintain homeostasisRespond to stimuli (irritability)Grow and reproduceAdapt and evolve

Cell Theory

The cell is the structural and functional unit of lifeAll living things are composed of one or more cellsCells can only come from preexisting cells

Types of Cells

Prokaryotic cells do not have a nucleus or membrane-bound organellesNot as complex, sophisticated, nor as large as eukaryotic cellsEukaryotic cells have a nucleus and membrane-bound organellesSubdivided by membranes into compartments

The Three Domains

It has been proposed to divide all living things into one of three domains:Archaea More closely related to Eukarya

BacteriaEukarya Contains all the eukaryotes

Five Kingdom SchemeMonera (Prokaryotae) Contains all the prokaryotes

Protista Estes defines as the “swing’ kingdom

Fungi PlantaeAnimalia

The Unifying Theme of Biology

Evolution is the unifying theme of biology “change through time”

Descent with modification Descent (life’s unity) and modification

(diversity)

Mechanism is natural selection Environment selects most suited traits

What is Science?

A process that involves testing possible solutions to a problem or understanding an event in nature.The process that science uses is known as the scientific methodWhat is the scientific method?

The Scientific Method

a way of getting informationan organized way of questioninginvolves rigorous testing of a proposed solutionOne aspect of the scientific method is observation.

Observations

the use of our senses to record an eventexamples of observation the leaves on that tree are different

from the others of the same kind of tree I urinate a lot when I drink coffee.

Observations are followed by forming a hypothesis and testing it.

Hypotheses

A hypothesis is a statement that provides a possible answer to a question or an explanation for an observation.Example-- Chemical A will kill weeds.

To test this hypothesis, we set up experiments and controls.

Experiments and Controls

Experiment recreation of an event in a way that enables

a scientist to support or reject a hypothesis. experimental group and a control group

Experimental group all members receive the experimental

treatment

Control group do not receive the experimental treatment

Definitions, continued

Placebo is typically an nonmedicated substance given to the control group NCTR studies time

Blind study: The participants do NOT know if they are in the control or experimental groupDouble-blind study: Participants and researcher(s) do NOT know which group is experimental and which is control

Testing our Hypothesis

Hypothesis: chemical A will kill weedsSelect two plots of soil with miscellaneous weeds growing on them.Treat one plot with chemical A Experimental Plot

Treat another plot with water Control Plot

Plot A treated with

Chemical A is the

experimental plot.

Plot B treated with

water becomes the

control plot.

Testing, ctd.

Allow two weeks to elapse.Count the number of living weed plants on Plot A and Plot B.Keep careful records of the appearance of the plots such as when signs of dying begin to develop.What do you expect to see?

Plot A Plot B

Conclusions

Chemical A will kill weeds under conditions of this study.Our hypothesis is supported by the experiment.One experiment is usually not enough to support a hypothesis.

Medicine and the Sci. Method

When you go to a physician, he or she collects data through the process of physical examination, lab. tests, and other means.The physician then formulates two hypotheses-- a diagnosis of your ailment a course of treatment to help you get better

Medicine, ctd.

You, the patient, then carries out the experiment by following whatever treatment protocol is prescribedIf you get well the hypothesis is supported.If you don’t get well the hypothesis is not supported and the physician formulates another hypothesis.

Theories and LawsTheory a hypothesis that has been supported by

years of repeated experimentation and evidence gathering.

“Germ Theory of Disease”

Law a widely accepted theory a constant fact of nature Law of Biogenesis

Two Mindsets of Science

Inductive reasoning is generalization that summarizes many concurrent observations

Specific to the generalHypothesis driven (Deductive) asks questions and seeks explanations

General to specificTakes form of prediction(s)

“if…then” logic

Believe it or Not

Peppered moths dataSpider mimic experimentsDDT; antibiotics; HIVTime for an Estesism