Chapter 1 Learning About Life

features of science

- Adheres to an established and well-recognized scientific method -Repeatable results - Testable claims that can be disproven - Open to outside review - Multiple lines of evidence

features of Pseudoscience:

- Does not adhere to generally accepted process of scientific method - Results that can not be duplicated, rely on a single person, or are solely opinion - Unprovable or untestable claims, reliance on assumptions or beliefs that are not testable - Rejection of external review or refusal to accept contradictory evidence - Overreliance on a small amount of data; underlying causes are not examined

controlled experiment

A component of the process of science whereby a scientist carries out two parallel tests, an experimental test and a control test. The experimental test differs from the control by one factor, the variable.

variables

A factor or condition of an experiment that is changed, often while keeping all other factors or conditions constant

independent variable

A factor whose value is manipulated or changed during an experiment to reveal possible effects on another factor (the dependent variable).

dependent variable

A factor whose value is measured in an experiment to see whether it is influenced by changes in another factor (the independent variable).

Pseudoscience

A field of study that is falsely presented or mistakenly regarded as having a scientific basis when it does not.

placebo

A harmless but ineffective procedure or treatment that is given purely for psychological reasons or to act as a control in a blind experiment.

fact

A piece of information that is correct based on all current information. A fact is not subject to opinion and can be independently verified.

negative feedback

A primary mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation.

natural selection

A process, proposed by Charles Darwin, in which individuals with certain inherited traits are more likely to survive and reproduce than are individuals that do not have those traits.

double-blind experiment

A scientific experiment in which some information is withheld from both the test subject and the experimenter. A double-blind experiment is meant to eliminate bias on the part of the participants and the researchers.

single-blind experiment

A scientific experiment in which some information is withheld from the test subject.

experiments

A scientific test, often carried out under controlled conditions, that involves changing just one factor (the variable) at a time.

experimental group

A set of subjects that has (or receives) the specific factor being tested in a controlled experiment. Ideally, the experimental group should be identical to the control group for all other factors.

theory

A widely accepted explanatory idea that is broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence.

Science

Any method of learning about the natural world that follows the scientific method.

The Relationship of Structure to Function

At all levels of biology, structure and function are related. Changing structure often results in an altered function, and learning about a component's function will often give insight into its structure.

Evolution

Charles Darwin established the ideas of evolution ("descent with modification") through natural selection (unequal reproductive success) in his 1859 publication The Origin of Species. Natural selection leads to adaptations to the environment, which—when passed from generation to generation—is the mechanism of evolution.

control group

In a controlled experiment, a set of subjects that lacks (or does not receive) the specific factor being tested. Ideally, the control group should be identical to the experimental group in all other respects.

Interactions within Biological Systems

Life can be studied on many levels, from molecules to the entire biosphere. As complexity increases, novel properties emerge. For example, the cell is the smallest unit that can possibly display all of the characteristics of life.

data

Recorded verifiable observations, the evidence on which scientific inquiry is based

artificial selection

Selection by humans for breeding of desired traits from the natural variation among different organisms

adaptation

The accumulation of favorable variations in a population over time

peer review

The evaluation of scientific work by impartial, often anonymous, experts in that same field. Peer review is considered a good means of recognizing valid scientific sources.

biosphere

The global ecosystem; the entire portion of Earth inhabited by life; all of life and where it lives.

Information Flow

Throughout living systems, information is stored, transmitted, and used. Within your body, genes provide instructions for building proteins, which perform many of life's tasks.

Pathways That Transform Energy and Matter

Within ecosystems, nutrients are recycled, but energy flows through and is lost.

hypothesis

a proposed explanation for a set of observations

anecdotal evidence

anecdotal evidence

The "gold standard" for a medical trial is a:

double-blind placebo-controlled study

genes

hereditary units of information consisting of specific sequences of DNA passed on from the previous generation

Properties of life are:

order, cells, growth and development, energy processing, regulation, response to the environment, reproduction, and evolution.

a valid hypothesis must be:

testable and falsifiable (able to be proven or disproven)

evolution

the process of change that has transformed life on Earth from its earliest forms to the vast array of organisms living today.

Biology

the scientific study of life