Introduction to Biology

Chapter One

What is Biology?

Science- an organized way of gathering and analyzing evidence about the natural world

Biology- the study of life

Themes of Biology

Cell Structure and Function

Stability and homeostasis

Reproduction and Inheritance

Evolution

Interdependence of organisms

Matter, energy and organization– *Can Sally Remember Every Idea Matters

Cell Structure and Function

Cell is the basic unit of life

Two categories– Unicellular- one cell– Multicellular- many

cells• As cells develop they

become different from each other (differentiation)

Source One

Stability and Homeostasis

Homeostasis- maintaining stable level of internal conditions– Example- body

temperature

Source two

Reproduction and Inheritance

Reproduction- process in which new organisms are produced

DNA- form in which genetic information is passed to offspring

Two Types of Repro– Asexual- only one

organism contributes• Example- bacteria

– Sexual- two organisms contribute to offspring

• Example- humans, frogs

Evolution

Evolution- study of the changes in organisms over time

Natural Selection- how evolution occurs

Natural Selection acts upon characteristics that are favorable to environment leading to more reproduction

Interdependence of Organisms

Ecology- study of the interactions of organisms

Ecosystem- environmental community

Source three

Matter, Energy, Organization

Photosynthesis- process in which organisms capture energy from the sun– Process that allows

all life on Earth to exist

Autotroph- organisms that make their own food from sun– Example- plants

Heterotroph- organisms that must consume others to meet energy needs– Example- humans

http://youtu.be/juxLuo-sH6M

Characteristics of Life

Reproduction

All cells

Respond to environment

Energy (obtain and use)

Homeostasis

Organized with DNA

Growth and development

Reproduction– Sexual– Asexual

All Cells– Unicellular– Multicellular

Respond to Environment– Stimulus- signal to

which an organisms responds

• Example- temperature, moisture, predators

Energy- all organisms must take in materials and energy to grow, develop, reproduce– Metabolism- sum of

all the reactions occurring in the body

Homeostasis- stable level of internal conditions

DNA- universal genetic code, stores information needed to live, grow and reproduce

Growth and development– All organisms grow

as a result of cell division and development

Cell Division- forming new cells from existing cell

Development- produced by repeated cell divisions and cell differentiation (cells becoming different from one another)– Example- heart cells,

bone cells, nerve cells

Scientific Method

Ask Question

Form hypothesis

Set up controlled experiment

Record and analyze results

Draw conclusion

Publish

Ask Question- based on something you have seen or noticed (observation)

Form hypothesis- statement that explains the observation and can be tested (prediction or educated guess)

Setting up Controlled Experiment

Experiment is conducted by gathering data under controlled conditions

Control group- group that contains all the norms

Experimental group- group that has just one variable different from control– Independent variable-

one factor that is purposely changed in experiment

– Dependent variable-change that occurs in response to independent variable

Record/Analyze Results

Data-any and all information gathered to try and answer original question– Quantitative-

numbers, measurements

– Qualitative- descriptions of observations

Recording- done in table or chart

Analyzing- looks at data to determine trends and is reliable– Type of analysis

varies depending upon experiment

Draw Conclusion- looks at analysis to determine if hypothesis is supported or rejected

Publish- write a scientific paper or lab report to publish in journal

Microscopes

Microscope- instrument that produces an enlarged image of an object

Source Four

Magnification- is the increase of an objects apparent size– Must multiply

eyepiece with objective lens to get total magnification

Resolution- ability to show details clearly, higher resolution= better picture

Good microscopes have both high magnification and high resolution

Types of Microscopes

Light- uses a light source to shine through specimen

– Most common type used by biologists

Electron- uses beams of electrons to produce enlarged image– Produce high

magnification, but can not be living

Two types– Transmission (TEM)– Scanning (SEM)

Source Five

Measurements

Metric System (SI)- system used around the world– Kept standard so no

conversions are required

We will always use Metric System in class

Length- meter (m)

Mass- gram (g)

Time- seconds (s)

Volume, liquids - liter (L)

Temperature- Celsius (C )

Metric System

All based upon the power of 10– Start at base unit,

use prefixes to determine number

– Example 5 kilometers; kilo=1000 so 5 km= 5000 meters

Giga=1,000,000,000

Mega= 1,000,000

Kilo= 1,000

Hecto= 100

Deka= 10

Deci= 1/10

Centi= 1/100

Milli= 1/1,000

Micro= 1/1,000,000

Level of Bodily Organization

Molecular- atoms together make organelles

Organelles- different parts of the cell that have specific job making up the cell

Cell- basic unit of life

Cont.

Tissue- group of cells working together to perform a specific function

Organ- two or more tissues working together to perform a specific function

Organ System- two or more organs working together for a common purpose

Organism- all the organ systems working together

– Heart cell, cardiac muscle tissue, heart, circulatory system, human

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http://www.pgbeautygroomingscience.com/assets/images/wosc/Chapter%202/Function%20Dermis%201.jpg

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