Intro to Biology: Principles and methods

Biology is the study of life

Biology has many subdisciplines• Biochemistry• Cell biology• Ecology• Physiology• Microbiology• Genetics• Molecular biology• Population genetics• Botany• Agriculture

• Bioinformatics• Systems biology• Health• Medicine• Pharmacology• Evolution• Anatomy• Taxonomy• Paleobiology• Etc., etc., etc.

Biology is transforming our lives

• As available biological information increases, our knowledge of biology advances

Biology is transforming our lives

• Antibiotics have saved countless lives

• Antibiotics are part of a constant war against microbes

• The war isn’t over yet

Biology is transforming our lives

• Oscar Pistorius, South Africa, 400m

• Fastest time: ~46 sec• World record: 43.18sec• Cleared to compete in

the Olympics

Knowing Biology is a good way to get a job

• Developments in biological knowledge have led to discovery of new drugs

• Many drugs require special manufacturing procedures

• The bay area is a pretty good place to get such a job

Knowing biology is a good way to get a job

• America has a rapidly aging population

• Jobs in healthcare are rapidly increasing

Knowing Biology is a good way to help out

• Biology addresses many needs and dangers the earth and its inhabitants currently face

What is life?

• We know it when we see it

• Characteristics not so easy to define

• Some are more basic than others

All living things consume and expend energy

• Heterotrophs- consume food from their environment

• Autotrophs- make their own food using other energy sources

• Lithotrophs- get their energy from oxidation of minerals

All living things are made of cells

• Cells are the basic units of living things

• Their size is determined by physical principles

All living things respond to their environment

All living things are orderly

• Life is self-organizing• Life controls its internal

environment in the face of external changes

All living things reproduce

• Bacteria reproduce by binary fission

• Daughter cells of bacteria are nearly identical

• But not quite…• Sexual reproduction

ensures offspring ar different from parents

All living things have DNA

• DNA is an orderly, self-replicating molecule

• DNA stores all genetic information

• It does not reproduce itself perfectly every single time

All living things evolve and adapt to their environment

• Variation in offspring allows natural selection

• Variation in offspring ultimately has its roots in imperfect replication of DNA

LE 1-6b

Population with varied inherited traits

Elimination of individuals with certain traits

Reproduction of survivors

LE 1-1a

Biosphere

EcosystemFlorida coast

CommunityAll organisms onthe Florida coast

PopulationGroup of brown

pelicans

OrganismBrown pelican

Life can be studied at all levels

LE 1-1b

OrganismBrown pelican

Spinal cord

Nerve Brain

Organ systemNervous system

OrganBrain

TissueNervous tissue

CellNerve cell Nucleus

OrganelleNucleus Molecule

DNA

Atom

New properties emerge at each new level of complexity

LE 1-8a-1

Observations

Question

Hypothesis #1:Dead batteries

Hypothesis #2:Burnt-out bulb

Hypothesis testing is the

means by which science

advances

LE 1-8a-3

Observations

Question

Hypothesis #1:Dead batteries

Prediction:Replacing batterieswill fix problem

Hypothesis #2:Burnt-out bulb

Prediction:Replacing bulbwill fix problem

Test prediction Test prediction

Test falsifies hypothesis Test does not falsify hypothesis

A good hypothesis

must be falsifiable

Good experiments are controlled

• Controls are references which can be used for comparison

Figure 1.8b

Figure 1.8c

Figure 1.8d

LE 1-8e

Artificial king snakes

Artificial brown snakes

84%

16%17%

Coral snakesabsent

Coral snakespresent

83%

100

80

60

40

20

0

Per

cen

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f to

tal

atta

cks

on

art

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ial

snak

es