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

What is Life?

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

• All living things share these characteristics:1. Organization2. Metabolism (growth and development)3. Reproduction4. Interaction/response to their environment5. Evolutionary adaptation6. 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 that occurs over a long

period of 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

6. Genetic component (DNA)

• All living organisms have DNA as their genetic blueprint

• DNA = deoxyribonucleic acid• Every cell uses DNA as its genetic

information to provide all structural and functional characteristics of the organism

• Every species has its own unique DNA blueprint.

Three Domains of Life

• Organisms can be grouped into three domains• Scientists classify organisms into a hierarchy of

groups in order to manage the great diversity of life for study– Grouped by fundamental characteristics– 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

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

Eukaryote = genetic material stored in a nucleus

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– Homo sapiens

Scientific Name

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

“bear”

“bear”

Scientific Method

• A systematic approach to understand the natural world– Observation– Hypothesis (educated guess based on observation

and previous scientific knowledge)• must be testable

– Experimentation• must be repeatable in order to confirm results are

not occurring by chance– Conclusion

• supports or rejects the hypothesis