Human Biology, Science, and Society

Chapter 1Gateway Community CollegeBiology 156

The Characteristics of Life Living things:

Have a different molecular composition than nonliving things

Require energy and raw materials Are composed of cells Maintain homeostasis Respond to their external environment Grow and reproduce Populations evolve

Different molecular composition All things on the earth are comprised of

the same 100 elements Only a few of these elements are used by

living organisms Living organisms can combine elements in

unique ways to form molecules Proteins Carbohydrates Lipids Nucleic acids Etc.

Non-living things

Require energy and raw materials Metabolism

The physical and chemical processes involved in transforming energy and molecules so that life can be maintained

Are composed of cells Cell

The smallest unit that exhibits all the characteristics of life

Unicellular Only one cell

Multicellular Many cells and many

different kinds of cells

Maintain homeostasis Homeostasis

Maintenance of the relatively constant internal environment

Regulation Selective barriers Tissues Organs Organ systems

Respond to external environment Reaction to environmental conditions

Grow and reproduce Grow and ultimately reproduce

Populations evolve

How Humans Fit into the Natural World 5 Kingsoms based on:

Presence or absence of a nucleus Number of cells Type of metabolism

Prokaryotes (1 Kingdom) No nucleus present

Eukaryotes (4 Kingdoms) Cell nucleus present

Kingdoms Monera

Bacteria Animalia

Animals Plantae

Plants Fungi

Mushrooms, yeast, etc. Protista

Protozoa

Prokaryote Domains Domain system

Further classification of prokaryotic organisms

The 3-domain system Bacteria Archae Eukarya

Comprises all 4 kingdoms

Humans Kingdom Animalia

Vertebrates Nerve cord and a

backbone Mammals

Vertebrates with mammary glands who nurse their young

Primates Human, apes, monkeys

Genus Second smallest unit of classification Humans are Homo sapiens Characteristics make us unique Interbreed

Species Smallest classification system One or more populations of organisms with

similar physical and functional characteristics Interbreed Produce fertile offspring under natural conditions

American Indian Asian African Caucasian Latino Mediterranean Indian Etc.

Defining Characteristics of Humans Bipedalism Opposable Thumbs Large Brain Capacity for complex language

Bipedalism Humans:

Stand upright Walk on two legs Frees our hands for work

Latin: bis = twice, pes = foot

Opposable Thumbs Fingers can be moved into

positions that oppose the thumb Finger tips can pinch together Other primates use the side of

the finger to grasp with the thumb

Large Brain Large brain mass relative to body size

Capacity for Complex Language Development of complex vocal language,

sounds, gestures, signs and symbols Communicates concepts and emotions Adaptation of language into written forms

Studying Levels of Organization Biology can be studied at any level

Numerous areas of study in the biological sciences

Atom and molecule Cell Tissue Organ Organ System

Organism Population Community Ecosystem Biosphere

The Scientific Method Test ideas

1. Observe and Generalize2. Formulate a hypothesis3. Make a testable prediction4. Experiment or Observe5. Modify Hypothesis if

necessary and repeat

Observe and Generalize Inductive reasoning

Specific to general

We observe something, and based upon past experience or knowledge, generalize what we see

It is starting to get cold outside winter is coming

Formulate a hypothesis

Tentative statement about the natural world

Leads to a testable deduction

An “educated guess” to explain what we observed

Make a Testable Prediction Speculation

Things that cannot be tested Hot air Half-truth Assumption

Testable predictions Very specific predictions Working hypothesis

Deductive reasoning Apply a general case to a specific one

If . . . then

Experiment or Observe Truth or falsehood is based

on an experiment or set of tests

Experiment Carefully planned and executed

manipulation of the natural world that has been designed to test your prediction

Performed using very-strict controlled conditions

Controlled experiments Variables

Modify Hypothesis and repeat If your prediction is false . . .

Modify your hypothesis to fit your experimental findings

If your prediction is true . . . Test further variables

Making the Findings Known Publication of findings

Presentations Articles Books Etc.

Pier-review Most accurate form of publication

Conditions of the experiment data are very specific

Theory Broad hypothesis Extensively tested Supported over time Explains a broad range of scientific facts High degree of reliability

Sources of Scientific Information Technical information is usually for the

scientific community Science magazines and nonfiction books

Designed for the well-educated public General interest magazines and daily

newspapers Get information out quickly

Internet .org, .com, .edu, etc.

Misinformation

Critical Thinking Become a skeptic Statistics Graphs Anecdotes and scientific evidence Separate facts from conclusions Understand the difference between

correlation and causation

Skepticism A questioning attitude

Statistics Organizing and interpreting information

and data Confidence Standard error

Graphs A picture speaks a thousand words

Anecdotal Evidence A testimonial or short unverified report A generalized statement that may be true

Facts and ConclusionsFact

Verifiable piece of informationConclusion

Judgment based upon facts

The news media often misuses, or confuses facts and conclusions

Correlation and Causation Correlation

Pattern or relationship between two variables Causation

What causes something to happen Correlation does not specify causation

Role of Science Science improves Technology and the

Human Condition Science has limits Make informed decisions