CP Biology
Unit 1: The Nature of Life
Chapter 1:
Characteristics of Life
All living things share the same
traits of life
Big Idea #1
1. Made of one or more cells
a. cell – basic unit of life
b. unicellular organisms
– bacteria, amoeba, etc.
c. multicellular organisms – cells specialize
Unicelled organisms
2. Have DNA
a. molecule carries instructions for all
life functions
b. Heredity – cells copy DNA and pass
it to offspring
c. “Universal” code – same for all
organisms
A C T G = letters in DNA code
Combining DNA from two organisms
Examples – human insulin
drought resistance
GM (genetically modified) foods
Genetically Modified Corn
Bacteria – toxin kills worm
Gene for toxin put into corn
Worm eats corn gene makes toxin  toxin kills worm
Why not hurt humans? Concentration too small
DNA is unique to an individual
DNA “fingerprint”
- a pattern of stripes/bands
- different for everyone
- depends on order of ACTG
3. Obtain and Use Energy
a. Food – for energy and raw materials
b. Producers – use sunlight to make food
c. Consumers – find food in environment
4. Exchange with the Environment
Big Idea #2
a. Materials cycle
b. Living things take in light, food, water, air
- For energy, materials for growth and repair
c. Remove wastes, die, decompose
d. All forms of life depend on each other and
on physical environment
a. Biotic and abiotic
Chemicals CYCLE
Environment
 producers
 consumers
 decomposers
 back to environment
Energy does NOT cycle
Sun  producers  other organisms. Energy
is used to sustain life, some lost as heat.
5. Grow and Develop
a. Grow – increase in size
Organisms have characteristic size and shape
• New cells start small, get bigger - to a point:
– Cells reach maximum size, then divide in two
• For organism to grow bigger – make more cells
b. Develop – change while maturing
a.
b.
c.
d.
e.
Multicelled begin as a single cell
Cells copy and specialize (differentiate)
Form many different kinds of cells
Organisms change as they grow older
Egg  embryo  young  adult
Bones grow longer with maturity
Stem Cells
a. Can become different kinds of cells
b. Depends on organism’s need, chemical
signals from their environment
6. Are organized
Big Idea #3 Simple-to-Complex
Cells and organisms – different parts
do specific functions
Levels of Organization in Multicelled
a. Cells - made of molecules, made of different
kinds of atoms
b. Cells differentiate  specialized cells
c. Different kinds of cells form tissues
d. Different kinds of tissues form organs
e. Organs work together to form organ systems
f. Body systems work together to keep the
entire organism alive.
Skin Tissue
• Many kinds of cells work together
Cells  tissues  organs
 organ systems  organism
Cells: muscle, blood,
lining, gland
Tissues: muscle,
blood, linings, glands
Organs: mouth,
throat, stomach,
intestine
Organ system:
digestive
Organization in the Environment
Organism – individual living thing, makes up a:
Population – group of one species living in an
area. These make up a:
Community – collection of living things in a
particular area. These make up an:
Ecosystem - collection of living and nonliving
things in a particular area. All these make up the:
Biosphere – layer on earth that supports life
7. Reproduce
Make new cells or new organism
• New cells – for growth, repair
• New organism – continues the species
Reproduce
a. By cell division
b. Asexual – one parent
- identical offspring
c. Sexual – two parents
- offspring gets genes
from both parents
- must be same species
Is mule a species?
Species – look similar and can
interbreed to form fertile offspring
Mule Parents – horse and donkey
Hybrid - offspring from two
closely-related species
- cannot reproduce
 NOT a species
8. Respond to environment
a. Stimulus - causes a reaction
b. Response - reaction to a stimulus
c. Internal or external stimuli
d. Must keep homeostasis (constant
internal conditions)
9. Evolve
Big Idea #4
a. Species can slowly change over time to
better fit an environment
b. Individual organisms DO NOT evolve
c. Earliest life 3.5 billion years ago
1.Evolution - Unifying Theory in Biology
Common Origin
a. all organisms descended from ancient early
life forms
b. changed over time into many different kinds
c. modern organisms – many different kinds
but show similarities in life processes,
molecules, DNA
2. Unity and Diversity
Life is unified – by evolution
- all living things do same life functions
- same chemical make-up and processes
 shared ancestor
Living things are diverse – by evolution
- special features for different environments
3. Structure and Function
a. “Form follows function”
b. Features evolve to perform a
function better
c. Different environments need
different kinds of adaptations
Are viruses alive?
• NOT part of living kingdoms
• LACK MOST traits of life, have only 3:
– Have DNA and protein
– Organized, recognizable size and shape
– Can evolve
• BETWEEN living and nonliving
Big Ideas in Biology
1. All life forms share common traits
– DNA, made of cells, do same life traits
1. Living things interact with each other and with
the environment (food chain, cycling)
2. Life proceeds from simple to complex
- levels of organization in organism, in environment
3. Evolution explains unity and diversity
a. Unity - All life forms share common traits
- cells, DNA, life functions
b. Diversity - Life evolves to suit its environment
– form and function
Life Processes
How do living things stay alive?
All life processes work to
maintain homeostasis
Metabolism – all the chemical processes
an organism performs
Maintain Homeostasis
Consistent, stable internal conditions
• External changes
– Temperature, light, sound, motion
• Internal changes
– pH, salt, water, ions, nutrients, wastes
• Cells/organisms respond to changes
• Must restore balance quickly to survive
1. Cellular Respiration
• Break down food molecules for
energy
• NOT digestion, NOT “breathing”
• Aerobic or anaerobic
2. Nutrition
• Get or make food; process it for cells to use
• Nutrients – for energy, raw materials
1. Autotrophs (producers)
a.
b.
c.
d.
Make their own food
Photosynthesis
Base for all food chains
Plants, algae, some bacteria
• Plants make food from small
compounds in the environment.
• Use sunlight energy
Autotrophs make food
for other organisms
2. Heterotrophs (consumers)
a. Take in food from environment
b. Digest – break large molecules down
3. Saprobes (decomposers)
a. break down wastes, dead organisms
b. recycle nutrient molecules
Digestive System
• Breaks down food
into molecules small
enough to enter cells
• Nutrients and water
absorbed by cells
• Liver, pancreas, and
others make enzymes
3. Transport
Move materials in a cell or organism
• Cross cell membranes
• Spread throughout cell
• Deliver needed materials, remove
wastes
• Multicellular – need way to transport
throughout organism
Animals have a
circulatory system
- heart, blood vessels
Plants have transport
tissue (veins)
4. Excretion
Remove chemical wastes
• Out of cell or organism  environment
• Wastes are toxic
• Animals have excretory system
• Kidneys, skin, lungs
• Plants have pores in leaves, stems
Excretory System in Humans
Kidneys – filter blood
Liver – detoxify wastes
Lungs – exhale CO2
Skin - sweat
5. Synthesis
Make any needed substance
• Use molecules from food or environment
• Use energy from cellular respiration
• Example: make muscle tissue from protein
6. Reproduction
Continue the species by making new organisms
7. Grow and Develop
Increase in size and mature
8. Regulation
Control rate and kinds of
chemical reactions
•
•
•
•
Respond to stimuli
Keep homeostasis
Unicelled, Plants – chemical messages
Animals – nerves and chemicals
Nervous system
• Electric signals along nerves
• Fast but short-live
Endocrine system
•
•
•
•
Hormones sent into blood stream
Cause response only in specific tissue
Slower, but last longer
Example: adrenaline, growth hormone
The Process of Science
Evidence: can be observed or
measured
1. Discovery science
- tries to describe nature
2. Experimental science
- tries to explain nature
- hypothesis – possible answer/ solution
- can be tested
Question  hypothesis  data  confirmation
Independent or Dependent?
• Variables – affect outcome
• Controlled Experiment – change ONE variable
• Independent variable – the one you change
“Manipulated”
• Dependent variable – depends on the
independent variable
“Responding”