Principles of Biology BIO 101

Prof. Marianne E. McNamara

Who Are You?

• Your major

• Your year/are you part time or full time

• Your plans

• Your interests

What is Biology?

• Biology is the study of life (bios = “life”; logia = “the study of”)

• Biology consists of several specialized disciplines– Botany: the study of plants– Zoology: the study of animals– Microbiology: the study of microorganisms

Why Study Biology???

• It’s EVERYWHERE!

Why Study Biology???

• Biology frequently plays a role in dealing with various challenges that face society

Why Study Biology???

• It’s AWESOME!!!

http://dsc.discovery.com/videos/planet-earth-highlights/

Why Study Biology???

• Biology is the scientific study of life!

http://www.croski.hr/fotogalerija/20021207200152slc2.jpg

www.luttyphoto.com

http://www.mnh.si.edu/exhibits/natures_best_2006/gallery/snowmonkeyandbaby.html

What is the definition of life?

• Life is a characteristic shared by ‘objects’ with self-sustaining biological processes

• All living things share these characteristics:– Organization– Metabolism (growth and development)– Reproduction– Interaction/response to their environment– Evolutionary adaptation– Genetic component (DNA)

1. Organization

• All living things are organized

• Life is organized in a hierarchical fashion– Hierarchy: any system of things ranked one

above another

Biosphere

EcosystemFlorida coast

CommunityAll organisms onthe Florida coast

PopulationGroup of brown

pelicans

Nucleus

Nerve

Spinal cord

CellNerve cell

TissueNervous tissue

OrganBrain

OrganelleNucleus Molecule

DNA

Atom

Organism Brown pelican

Organ systemNervous system

Brain

Hierarchy of Life

• Ecosystem• Community• Population• Organisms• Systems• Organs• Tissues

• Cells• Molecules• Atoms

Level

2. Metabolism

• All living things metabolize

• Metabolism = set of chemical reactions necessary to maintain life– Metabolism is management of ENERGY;

organisms TAKE energy from their environment, transform and use it

– Allows organisms to grow, reproduce, maintain structural stability, and respond to their environments

Metabolism

• Autotrophs – transform energy from their environment (the “producers”)– Plants are autotrophs; they transform the

sun’s energy into energy-rich molecules that support life

• Heterotrophs – ingest their energy from their environment (the “consumers”)– Animals are heterotrophs; they ingest (eat)

food to obtain energy-rich molecules

3. Reproduction

• All living things reproduce

• Reproduction can be sexual, asexual, or both!

4. Interaction/response to environment

• All living things interact and respond to their environment

• Living things respond to environmental stimuli (scent, sight, sound, touch, taste)

• Living things exchange gases (carbon dioxide, oxygen, etc) with their environment

Environmental interaction

A Venus flytrap responds to the stimulus of a dragonfly landing on it

5. Evolutionary adaptation

• All living things evolve• Evolution is a gradual change over a long

period of time (most of the time!)• Evolution explains the diversity and

adaptations of life• Evolution is the change in genetic

material of a population of organisms from one generation to the next (we’ll come back to this)

6. Genetic component (DNA)

• All living organisms have DNA as their genetic blueprint

• DNA = deoxyribonucleic acid

• Every cell uses DNA as its genetic information

• Every species has its own unique DNA sequence.

Three domains of life

• Organisms can be grouped into three domains

• Scientists classify organisms into a hierarchy of groups– Grouped by fundamental characteristics– Helps scientists manage the great diversity of

life for study– Not always clear-cut; organisms do not

always fall into structured categories

Three domains of life

• All organisms are grouped into three domains– Domain Archea– Domain Eubacteria– Domain Eukarya

Eukaryote = genetic material stored in a nucleus

Prokaryote = no nucleus; genetic material ‘loose’ in cell

Prokaryotic

Eukaryotic

Classification

• Domains are further classified/categorized into:– Kingdom– Phylum– Class– Order– Family– Genus– Species

Domain

Kingdom

Phylum

Subphylum

Class

Order

Family

Genus

Species

Diversification

Scientific name

• Organisms are ultimately sorted to the species level (species that appear to be closely related are grouped into the same genus_

• Binomial (“two part”) system: genus and species constitute the scientific name of the organism

• Genus is always Capitalized and species is always lower-case; both are in italics

Scientific name

• Why all the fuss? Common names can be deceiving…

http://www.ticam.utexas.edu/images/grizzly.jpg

“bear”

“dolphin”

Scientific name• Scientific names are descriptive

• May describe unique characteristic, region where species is found, etc.

• Example: Humpback whale Megaptera novaeangliae – Magas = large– Pteron = wing– Novas = new– Angaliae = England

Scientific Method

• A systematic approach to understand the natural world– Observation– Hypothesis

• Must be testable

– Experimentation• Must be repeatable• Multiple trials necessary

– Conclusion• Supports or rejects the hypothesis

Hypotheses can never be proven!!!