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Introduction to Biology

Biology – The Study of Life

• Section 1: The World of Biology• Section 2: Themes in Biology• Section 3: The Study of Biology• (Section 4: Tools and Techniques ~

will be covered in separate power point)

HUTCHCROFT

Introduction to Biology• Biology: The study of life

• Life arose more than 3.5 billion years ago in Archean eon of Precambrian period

• First organisms (living things) were single celled (unicellular); Only life on Earth for millions of years

•Organisms changed over time (evolved)

• First multicellular organisms arose in the Proterozoic eon of Precambrian period between 550 million and 2.5 billion years ago!

Introduction to Biology• New organisms arose from older kinds ! Today, estimates suggest 10 – 100

million organisms may exist!!!!!!!!! Only 1.5 million of these have been named!

• 99% of organisms that EVER existed may already be extinct, having never been identified and named!!

• 99% of all animal species are smaller than bumble bees!

• Organisms inhabit almost EVERY region of the Earth today!

The World of Biology

• Biology: The study of life• Characteristics of life

• Organization and Cells• Response to Stimuli• Homeostasis• Metabolism• Growth and Development• Reproduction• Change Through Time

Organization and Cells• All living things are composed

of one or more cells• Cells are the smallest units

that can perform all life’s processes

• In multicellular organisms, many are specialized to perform specific functions

• Cells are always very small• The size of multi-celled

organisms depends on the number of cells NOT their size

Organization and Cells, cont.

• Organized at both the molecular and cellular levels

• Take in substances from the environment and organize them in complex ways

• Specific cell structures (organelles) carry out particular functions

• In multicellular organisms, cells and groups of cells are organized by their function (hierarchy of life)• Atom Biological Molecule Organelle Cell

Tissue Organ Organ System Organism

I don’t care what you say – that’s funny right there!!! LOL!!

11stst Level of Organization Level of Organization• Organism:Organism:

An individual living An individual living thing that is made of thing that is made of cells, uses energy, cells, uses energy, reproduces, reproduces, responds, grows, and responds, grows, and developsdevelops

Want more? How about the whole hierarchy of Life from the organism on……

22ndnd Level of Organization Level of Organization• Population:Population:

A group of A group of organisms, all of organisms, all of the the same speciessame species, , which which interbreedinterbreed and live in the and live in the same place at the same place at the same timesame time..

33rdrd Level of Organization Level of Organization

• BiologicalBiological

Community:Community:All the All the populations of populations of different speciesdifferent species that live that live in the same place at the in the same place at the same time and interact same time and interact (solely biotic in terms of (solely biotic in terms of composition).composition).

44thth Level of Organization Level of Organization• Ecosystem:Ecosystem:

Populations of plants and Populations of plants and animals that interact with animals that interact with each other in a given each other in a given area, along with the area, along with the abiotic components abiotic components (physical and chemical) of (physical and chemical) of that area. that area. [[terrestrial or terrestrial or aquatic]aquatic]

55thth Level of Organization Level of Organization• Biosphere:Biosphere:

Broadest, most Broadest, most inclusive level, i.e., inclusive level, i.e., the thin volume of the thin volume of Earth and its Earth and its atmosphere that atmosphere that supports life (5 to 6 supports life (5 to 6 miles above surface miles above surface to deepest part of the to deepest part of the oceans)oceans)

•Earth:apple::biosphere:skin of Earth:apple::biosphere:skin of appleapple

Response to Stimuli

• Organisms can respond to a stimulus, or a physical or chemical change in the internal or external environment

Homeostasis• The maintenance of a stable level of internal conditions even though environmental conditions are

constantly changing, e.g., body temperature, water content, glucose levels

Metabolism• The sum of all the chemical reactions that take in and transform energy

and materials from the environment

PHOTOSYNTHESIS

Metabolism• ALL energy comes from the SUN (directly or indirectly)• Photosynthesis is the process by which some organisms capture the energy from the sun (solar) and

transform it into energy (chemical) that can be used by living things

PHOTOSYNTHESIS

Metabolism• Organisms that make their own food are called autotrophs• Phototrophs – use solar energy (photosynthesis) to get energy• Convert H2O and CO2 into sugar and O2• Chemotrophs – use different chemical processes to get energy• Organisms that must take in food to meet their energy needs are called heterotrophs

Consume autotrophs (herbivores), other heterotrophs (carnivores) or both (omnivores) for their energy needs• Complex chemicals are broken down and reassembled into chemicals and structures needed by organisms

Growth and Development• All living things grow and increase in size from the division and

enlargement of cells

• Development is the process by which an organism becomes a mature adult; involves cell division and cell differentiation, or specialization

Reproduction• Production of new organisms is essential for the continuation of a species

• Hereditary information is transferred to offspring during two kinds of reproduction• Sexual reproduction – hereditary information

recombines from two organisms of the same species

• Asexual reproduction – hereditary information from different organisms is not combined ~ original and new organisms are genetically the same

Evolution or Change Through Time

• Populations of living organisms evolve or change through time to better adapt to changing conditions

• Charles Darwin’s SURVIVAL OF THE FITTEST through the process of natural selection

THEMES IN BIOLOGY• Diversity and Unity

• Unity in the Diversity of Life• Three Domains of Life

• Interdependence of Organisms• Evolution of Life

• Natural Selection

Unity in the Diversity of Life• Genetic code: rules that govern how cells use the hereditary information in DNA (deoxyribonucleic acid – makes up our genes or instructions for life)• Presence of organelles: carry out all cellular activities• “Tree of Life” – suggests all living things have descended with modification from a single common ancestor; thus, all of life is connected

Three Domains of Life• Bacteria

• Kingdom Bacteria (Eubacteria)• Archaea

• Kingdom Archaea (Archaebacteria)• Eukarya

• Kingdom Animalia• Kingdom Plantae• Kingdom Fungi• Kingdom Protists

Interdependence of Organisms• Ecology: branch of biology that studies organisms interacting with each other and with the environment• Ecosystems: communities of living species and their physical environments; e.g., minerals, nutrients, water, gases,

heat, etc.

Evolution of Life• Descent with modification: process in which the inherited characteristics within populations change over generations, such that genetically distinct populations and new

species can develop• Natural Selection: organisms that have certain favorable traits are better able to survive and reproduce successfully than organisms that lack these traits• Adaptations: traits that improve an individual’s ability to survive and reproduce

Scientific Method

Scientific Processes and Methods• 1. Observations/Questioning• 2. Measuring, Organizing Data, and

Classifying • 3. Hypothesizing -- a testable explanation

based on experience, reading, and/or previous experiments. (NOT A GUESS)• Inductive Reasoning

• 4. Predicting -- stating in advance the result that will be obtained from testing• Deductive Reasoning (If…then…statement)

Scientific Method, cont.

• 5. Experimenting -- A controlled procedure for testing a hypothesis• Control Group -- all conditions remain

constant• Experimental Group -- same as control,

except for ONE factor• Variable

• Independent Variable - condition that changes

• Dependent Variable - response to changed condition

• Data• Qualitative ~ descriptive• Quantitative ~ numbers

Scientific Method, cont.

Scientific Method, cont.

• 6. Organizing and Analyzing Data

Scientific Method, cont.

• 7. Inferring Conclusions (concluding from evidence collected during experimentation using facts and previous knowledge rather than direct observtions)

• 8. Modeling and Communicating

• 9. Test and Re-test ~ law or theory formed

Scientific Method, cont.

• LAW -- general statement that describes a wide variety of phenomena• If a hypothesis describes HOW things

happen and continues to be supported by evidence, it becomes a law.

• THEORY -- most probable explanation for a set of data based on best available evidence• If a hypothesis describes WHY things

happen and continues to be supported by evidence, it becomes a theory.

Scientific Method -- Example

• Observations:• Fish populations in Twin Lakes are declining.

• The pH (acidity) of the water in the lakes is dropping to 4.2.

• One hundred miles west of Twin Lakes is a power plant that is burning tons of coal every year, releasing sulfur dioxide into the air.

Problem

West Branch

• Twin Lakes -- Acid Rain Problem

East Branch

Power Plant

100 miles

Questioning/Hypothesizing(Inductive Reasoning)

• Question: Is there a link between the power plant, the pH of the lake, and the fish decline?

• Hypothesis: If acid rain falling on Twin Lakes is related to fish reproduction, then increasing acid rain amounts will cause the fish to have poor reproduction.

Experiment

• Experiment• Twin Lakes is a lake in the mountains that can be

divided by a barrier.• A complete inventory will gather baseline data.• One arm of the lake, on the east side of the barrier,

will be treated with sulfuric acid to reduce the pH to 4.0.

• The west arm of the lake will be left alone, other than monitoring.

Experiment

West Branch

• Twin Lakes -- Acid Rain Problem

East Branch

Power Plant

100 miles

No Acid Added Acid Rain Added

Barrier

Results

• East Branch: • Fish stop reproducing.

• West Branch: • No change in fish reproduction.

Conclusion

• The power plant emits sulfur dioxide into the air which combines with rain to produce acid rain. The addition of this acidic rain to the lakes lowers the pH and causes the fish to stop reproducing. This results in declining fish populations and jeopardizes the survival of the fish.