BIOLOGY 110: GENERAL BIOLOGY Lesson 1

Specific ObjectivesUnderstand the tenants of Biology as a field of scienceKnow the properties of living and non-living thingsUnderstand that there is diversity in living organismsUnderstand the concept of a species and hierarchical classification Describe the highest levels of classification, including the 6 kingdoms and 3 domainsKnow the basic theories of evolution, including Darwins natural selection

Understand the process of scientific investigation and some basic history of scientific thought

Understand and apply scientific methods and study design in research

What is Science?Science (Latin scientia: meaning "knowledge" or "knowing)the effort to discover, and increase human understanding of how the physical world works.

systematic observation of natural events and conditions in order to discover facts about them and to formulate laws and principles based on these facts.

the organized body of knowledge derived from systematic observations and that can be verified or tested by further investigation.

Many branches or general bodies of knowledge

What is BiologyGreek: bio= life, logy= study of

The scientific study of life and of living organisms.

Some branches; botany, zoology, and ecology etc.

Unifying Themes in BiologyOVERVIEWInformation transfer:~ hereditary information is passed from on generation to the next, and it controls the development and life of each cell

Energy for life~ energy from the sun is converted to chemical energy which is used to drive chemical processes within cells

Evolution~ biologys core theme; differential reproductive success ; POPULATIONS CHANGE OVER TIME

Characteristics of Life

Organisms are organized Grow and developRespond to stimuliCapture and use energy (metabolism)Regulate their internal environmentReproduceEvolve and become adapted

Characteristics of LifeOrganisms are organized Composed of cellsCell theory: new cells originate only from pre-existing cellsProkaryotic vs. eukaryotic cellsSingle celled vs. multicellular organisms

Prokaryotes and EukaryotesMonerans (bacteria) have prokaryotic cells. All are unicellular organisms.Protists, Fungi, Plants and Animals have eukaryotic cells. These may be unicellular or multicellular

Hierarchy of Organization AtomMoleculeCells (single cell organisms)TissuesOrgansOrgan SystemsMulticellular OrganismsLiving Things are ORGANIZED

Characteristics of Life (continued)Organisms grow and developGrowth- an increase in cell size, cell number or both.

Development- All the changes that take happen during an organisms lifespan

Characteristics of Life contd3. Organisms respond to stimuli

Living things react to stimuli (physical and chemical changes in their internal and external environments). Responding typically involves some form of movement

Movement may be created by Cilia & Flagella; Bones and Muscles; Expansion of certain cells to orient leaves to sunlight

Characteristics of Life (continued)4. Organisms capture and use energy

Metabolism- the sum of all the chemical reactions within an organism- Energy producing pathways (eg. photosynthesis)- Energy releasing pathways (eg. cellular respiration)

Characteristics of Life (continued) 5. Regulate their internal environment via Homeostasis- maintaining a constant internal environment

Regulated by feedback systems- Negative vs. positive feedback systems

Feedback Regulation: Negativecounteract the stimulus that is disrupting homeostasis

Typically accumulation of an end product of a process slows that process

Example: sugar breakdown generates ATP; excess ATP inhibits an enzyme near the beginning of the pathway

Feedback Regulation: PositiveWhen the original stimulus enhances the response

An end product speeds up its production

Examples: blood clotting in response to injury; uterine contractions

Organisms reproduceAsexual reproduction (One gives rise to two or more) Sexual reproduction: (gametes fuse to form a zygote)Characteristics of Life (continued)

Characteristics of Life (continued)Populations evolve and adaptEvolution- changes in population over time

Adaptations- inherited characteristics that increases an organisms chance of survive in a particular environment

Adaptations may be structural, physiological, and/or behavioural

Upper Levels of the HierarchyPopulationCommunityEcosystemBiosphere

Information Transfer Information transfer occurs Within organismsCell to cell chemical signalsNerve cells; Hormones

Between organismsBehaviour; Chemical communication (pheromones)

Among generations

Information encoding the instructions for the sustenance of life is transferred from one generation to the nextDNA is the hereditary molecule

Classification of organisms by Evolutionary RelationshipMost biologists now recognize six (6) kingdoms

Early biologists only recognized the plant and animal kingdoms

Some biologists split the bacteria into 2 separate kingdomsKingdom Archaebacteria (unique group of organisms recently have split off from the bacterial kingdom)

Kingdom Eubacteria (bacteria)

Kingdom Protista (protozoans and algae, molds)

Kingdom Fungi (mushrooms, molds, and yeasts)

The animals are in kingdom Animalia

Plants belong to kingdom Plantae

Classification of organisms by Evolutionary RelationshipThe diversity of the world today is extremely vast

Biologists use a binomial system for classifying organisms

Developed by Carolus Linnaeus

Binomial nomenclature describes the genus and species of the organism (genus + specific epithet

Taxonomy (the science of classification) is hierarchical a. Kingdoms- phyla- classes- orders- families- genera- species

Classification of organisms by Evolutionary Relationship3 Domains have been recently recognized into which the 6 kingdoms have been placedArchaeaBacteriaEukarya

Classification of organisms by Evolutionary Relationship

Energy & LifeLife depends on a continuous input of energy from the sun

Energy flows through individual cells and organisms

Cellular respiration produces energy (ATP) for most cells

Energy & LifeEnergy flows through ecosystems

1. Energy flows from producers to consumers to decomposers

2. Producers manufacture their own food a. Producers (autotrophs) are typically photosynthetic

3. Consumers (heterotrophs) obtain energy by eating producers

4. Decomposers obtain energy from wastes and dead organisms (eg. various bacteria and fungi)

Energy Flow through Ecosystem

The Process of Science Biology is studied using the scientific method

Like other sciences it is based on systematic thought processes including both deductive and inductive reasoning

Deductive reasoning works from the more general to the more specific. ("top-down" approach); Theory- hypothesis- observation- confirmation

Inductive reasoning works the other way, moving from specific observations to broader generalizations and theories. ("bottom up" approach); Observation- pattern- tentative-hypothesis- theory

Scientists make careful observations and recognize problems

The Process of Science

The Process of Science A hypothesis is a proposed explanation which is testableA prediction is a logical consequence of a hypothesisPredictions can be tested by experimentationScientific experiments include experimental and control groupsScientists draw conclusions from the results of experimentsA well-supported hypothesis may lead to a theoryA theory which is nearly universally accepted is a principle Laws are principles of the greatest importanceScience has ethical dimensions

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