Chapter 1The Science of Life

Biology Organization Cell Unicellular Multicellular Organ Tissue Organelle

Section 1 Vocabulary Pretest

A. Made of one cellB. The smallest unit that can perform

all life’s processesC. Made of many cellsD. The study of lifeE. The high degree of order within an

organism’s internal and external parts and in its interactions with the living world.

F. Tiny structures inside living cellsG. A group of similar cells working

togetherH. A group of tissues that work

together to perform a specific job in a living thing.

Biological molecule

Homeostasis Metabolism Cell Division Development Reproduction Gene

I. The sum of all chemical reactions in a living thing that take in and transform energy and materials from the environment

J. Formation of two new cellsK. Chemical compounds made up of

atomsL. A short segment of DNA that had

coded instructions for a single trait in an organism

M. To produce new organisms similar to oneself

N. Process by which an organism becomes a mature adult

O. To maintain stable internal conditions

Biology D Biological Molecule K Organization E Homeostasis O Cell B Metabolism I UnicellularA Cell Division J Multicellular C Development N Organ H Reproduction M Tissue G Gene L Organelle F

Answer Key

Biology is the study of life◦ From the Latin:

Bios = life and ology = study of

What is Biology?

1. Cellular Organization◦ Organization is the high degree of

order within an organism’s internal and external parts and in its interactions with the living world.

◦ All living things are made of one or more cells and these cells are highly organized. Unicellular = made of one cell

Multicellular = made of many cells

7 Characteristics of Life

Atoms are the smallest particle of an element. They combine to form:

Biological molecules which are chemical compounds that join to form:

Organelles —Each of these tiny structures within a cell has a special job to do to keep the cell alive

The cell is the smallest unit of life A group of cells working together

make up a tissue A group of tissues make up an

organ Organs combine to form organ

systems An organism is a complete and

whole living thing

2. Response to stimuli◦ A stimulus is a sudden change in an organism’s

environment◦ All organisms must be able to respond or react to

these sudden changes

3. Homeostasis is the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing.

4. Metabolism is the sum of all the chemical reactions that take in and transform energy and materials from the environment.◦ Different organisms have different metabolic rates

Describes as a fast or slow metabolism

5. Growth and Development◦ All living things grow or increase in size◦ Growth results from the division and enlargement

of cells◦ Cell division is the formation of two new cells

from an existing cell.◦ Development is the process by which an

organism becomes a mature adult.◦ A multicellular organism is composed of

trillions of specialized cells, all which developed from a single cell, the fertilized egg.

6. Reproduction◦ All organisms produce new organisms like

themselves. This is essential for the survival of the species.

Hereditary information is passed from parent to offspring on the coded information molecule known as deoxyribonucleic acid or DNA.◦ A gene is a short

segment of DNA that contains the instructions for a single trait of an organism.

7. Change Through Time◦ All populations of living things evolve or

change through time. This is important for species survival in a changing world.

◦ This also helps to explain the diversity of life-forms on Earth.

Domain Kingdom Ecology Ecosystem Evolution Natural Selection Adaptation

Section 2 Vocabulary Pretest

A. Communities of living species and their environments

B. Branch of biology that studies how organisms interact with the environment

C. Largest division in the classification of living things

D. Traits that improve an individual’s ability to survive

E. Theory stating that organisms with favorable traits are more likely to survive and pass on those traits

F. Second largest division in the classification of living things

G. Descent with modification

Domain C Kingdom F Ecology B Ecosystem A Evolution G Natural Selection E Adaptation D

Answer Key:

Three important themes help explain the living world and are part of biology◦ Diversity and Unity of

Life◦ Interdependence of

Organisms◦ Evolution of Life

Three Themes in Biology

1. Diversity and Unity of Life◦ These terms seem to

contradict each other Diversity = variety. Over

1.5 million species of living things exist on Earth. They are extremely different from each other.

Unity = similar. There are certain genetic similarities common to all living things, no matter how different they appear to be.

All living things have a genetic code found in the DNA molecule.

They share certain genes, yet no two types of organisms have the same full set of genes.

A tree of life places organisms with more similarities in their genes on closer branches.

All life is connected, yet there are different lineages representing different species.

The three branches represent the three Domains in the living world: Archaea, Bacteria, and Eukarya

Most scientists also recognize six kingdoms:◦ Archaeabacteria◦ Eubacteria◦ Protista◦ Fungi◦ Plantae◦ Animalia

2. Interdependence of Organisms◦ Organisms interact with each other. Nothing can

survive completely independent of another living thing. Ecology =the branch of biology that studies how

organisms interact with each other and their environment.

Ecosystem = communities of living species and their physical environments.

3. Evolution of Life◦ Populations of living organisms change through

time or “evolve” Evolution =descent with modification. It is the

process by which the inherited characteristics of a species change over time.

Natural Selection = theory that states organisms with traits best suited to their environment will most likely survive and pass on those favorable traits. It explains how species evolve and new species emerge.

Adaptation = traits that improve an individual’s ability to survive. Genetic variety allows some organisms to be born with favorable adaptations.

Scientific Method Observation Hypothesis Prediction Experiment Control group Experimental group Independent variable Dependent variable Theory Peer review

Section 3 Vocabulary Pretest

A. Forecasts what would happen in a test

B. Used to test a hypothesisC. Organized set of steps used to

solve a problemD. Provides a standard for

comparisonE. The act of perceiving somethingF. A proposed explanationG. A highly tested and generally

accepted principle that explains an observation

H. Experts critique each others workI. A.k.a. manipulated variableJ. A.k.a responding variableK. Group in which one factor is

different

Scientific method C Observation E Hypothesis F Prediction A Experiment B Control group D Experimental group K Independent variable I Dependent variable J Theory G Peer review H

Answer Key:

The scientific method is an organized set of steps used to solve problems:◦ Make an Observation —perceive a

natural occurrence which causes you to pose a question

◦ State the Question◦ Hypothesize and Predict—give an

explanation that tries to answer the question and then make predictions as to what would happen if the hypothesis were true.

◦ Experiment—design and run a test for the hypothesis

◦ Analyze Data and Draw Conclusions◦ Publish Conclusions—so that others can

verify, reject, or modify your results.

Scientific Method

A good experiment is called a controlled experiment. It has several parts:◦ Control group —this group provides a normal

standard against which results are compared◦ Experimental group —this group is identical to

the control group except for one factor◦ Independent variable —the factor that changes

in an experiment. Also called the manipulated variable.

◦ Dependent variable —the factor that is being observed or measured. Also called the responding variable.

The Experiment

Scientists collect two types of data:◦ Quantitative Data —data measured in numbers◦ Qualitative Data —data recorded as a

description of something◦ Both must be detailed

Data

A scientific theory is a highly tested, generally accepted principle that explains a vast number of observations and experimental data.

Examples: Cell Theory, Quantum Theory, Theory of Relativity, Theory of Natural Selection

Scientific Theories

A typical research paper has four sections:◦ Introduction —states the

problem and hypothesis to be tested

◦ Materials and Methods —describes the experiment

◦ Results —states the findings◦ Discussion —gives the

significance of the experiment and future directions the scientist will take.

Research Papers

The microscope will be used quite often throughout this course. Proper use will be covered in a lab activity.

The metric system will be used to take measurements in several lab activities. The metric system will be reviewed during that time.

Microscopes and Metrics