Principles of Biology BIO 101 Prof. Marianne E. McNamara.
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Transcript of Principles of Biology BIO 101 Prof. Marianne E. McNamara.
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???
• Biology frequently plays a role in dealing with various challenges that face society
Why Study Biology???
• Biology is the scientific study of life!
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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
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
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
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…
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“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