What is science?

• Science is an organized way of gathering and analyzing evidence about the natural world.

– Way of observing

– Way of thinking

– Way of “knowing”

• Science is not a “thing” → it’s a process!

Science as a process

• The process of science is….1. Dealing ONLY with the natural world around us

2. Collecting and organizing information they find, looking for patterns.

3. Proposing explanations based on evidence.

• Scientists want to find explanations for the world around us…one goal of science is to investigate, understand and analyze data, and provide explanations about the world.

Q: How do we explore the world around us?

• What senses do you use?

• Science is based on observations.

Observations lead to → Questions

Questions lead to → Experiments

This is the

Scientific Method!

HypothesisA prediction based on an observation

• Only useful if it can be tested• Always very specific

• It’s NOT a question – always phrased as a statement of what you BELIEVE.

Bad Hypothesis Good Hypothesis• Hermit crabs like colorful

shells

• Plants will grow better when given Miracle Grow.

• Hermit crabs choose colorful shells over drab shells

• Plants will grow taller when given Miracle Grow

Experimentation• After you form your hypothesis, you need to test

it! An experiment is a designed, planned procedure.

In your experiment you must have 2 groups:

Experimental Group Control Group

• Receives the treatment

• This is the group that you will be exposing to the procedure

• Receives NO treatment (placebo)

• This group does not get treated, it is used to represent what “normally occurs in nature when left alone”

What is Biology?

So what makes something “alive”?(What characteristics do all living things have in

common?)

Biologists have come up with the following 7 characteristics for all living things:

Living Things:

1. Use Energy2. Made of Cells3. Respond to a Stimulus4. Reproduce5. Grow & Develop6. Have a Genetic Code7. Adapt to their Environment

Notice: Motion is NOT on this list!

Let’s PracticeTell if the object is living or nonliving.

NonlivingLiving

Living

Living LivingLiving

Nonliving

Unit 1:Structure and Function

of Life

Organization of Living Things

Organization of Living Things

– Basic unit of matter• There are particles that atoms can be split into, but in

general we considered this the basic unit of matter

Atoms

**Note: This is NOT what they actually look like!

– When two or more atoms are bonded together

– Can be large or small

– Hold energy in their bonds

Molecules

– Basic unit of life• Nothing smaller than a cell can be considered alive

– Contain specialized organelles

– Two types• Eukaryote (have a nucleus)

• Prokaryote (do not have a nucleus---bacteria)

Cells

Prokaryotes vs. Eukaryotes

• Some organisms are unicellular– Only made of one cell

– Make up most of the living things on Earth!!!

– Have everything they need to survive in one cell.

– Colony: a group of cells that live together but maintain their own individual existence

• Example: Bacteria tend to live together in group but are individuals.

Unicellular Organisms

• Some organisms are multicellular– Made of many cells.

• In multicellular organisms, cells exhibit specialization.

– They take on specific jobs and look different from each other.

• The cells also exhibit division of labor. – They split up the work of the organism.

Multicellular Organisms

• In multicellular organisms, the cells specialize to perform specific functions. • Examples: bone cells, skin cells, nerve

cells, root cells, leaf cells• Start as stem cells and then differentiate

Smooth muscle Nerve cell Leaf cell Red Blood Cell

Specialization/Labor Division

Levels of Organization• Tissues—Groups of similar cells that work

together to perform a specific function.

– 4 major tissue types in animals

• Epithelial tissue

• Connective tissue

• Muscle tissue

• Nervous tissue

Epithelium (Human Skin)Muscle Tissue

• Organs—structures made of different types of tissues that work together to perform a specific function.

– Examples• Heart

• Lungs

• Stomach

• Liver

• Plant Roots

• Plant Stems

• Plant Leaves

Levels of Organization

• Organ Systems—Groups of organs that work together to perform a specific function.

– Examples:• Digestive system

• Circulatory system

• Respiratory system

• Nervous system

• Muscular system

• Skeletal system

• Integumentary system (skin)

• Vascular system in plants

Levels of Organization

• Organism—A complete, individual living thing.

– Examples:

• A single person

• A single plant

• A single bacterium

• A single protist

Levels of Organization

Body Systems

• Organs working together for larger goals

Amoeba Sisters: Body Systems

Body Systems: Nervous

Body Systems: Respiratory

Body Systems: Cardiovascular (Circulatory)

Body Systems: Digestive

• Takes in food, breaks it down into nutrient molecules and absorbs them.

– Uses mechanical means

– Uses chemical means

• Enzymes break down large organic molecules into monomers.– Pepsin = Stomach enzyme

– Salivary Amylase = Oral enzyme

• Gets rid of indigestible waste

Body Systems: Skeletal

Body Systems: Muscular

Body Systems: Integumentary

Body Systems: Endocrine

How Body Systems Work Together

• Almost everything you do requires more than one body system working together.

• What examples of body systems working together can you think of?

**Note: We will just assume that the nervous system is involved in everything**

How Body Systems Work Together: Food Intake and Usage

• What body systems do you think are involved?

How Body Systems Work Together: Food Intake and Usage

• Eating:

– Muscular/Skeletal

• Digestion

– Digestive

• Absorption

– Circulatory

– Happens in Small Intestine

How Body Systems Work Together: Breathing

• What body systems do you think are involved?

How Body Systems Work Together: Breathing

• Breathing

– Respiratory

• Bring in oxygen

• Let out Carbon Dioxide

– Circulatory

• Circulate oxygen around body

• Collect Carbon Dioxide from around body

How Body Systems Work Together: Exercise

• What body systems do you think are involved?

How Body Systems Work Together: Exercise

• Muscular/Skeletal– Movement

• Respiratory– Increased Oxygen intake– Increased Carbon Dioxide output

• Cardiovascular– Increased heart rate and blood flow

• Move oxygen/CO2 and decrease body temperature

• Integumentary – Sweating

Diffusion• In any solution, particles will tend to spread out.

(ex: sugar in tea)

• Diffusion: the movement of particles from highconcentration to low concentration.

Think of it as a slide…you naturally go from high to low…

Diffusion• Diffusion is the driving force behind movement

of substances across cell membranes.

• If a substance is present in unequal concentrations on different sides of the

membrane, If it can cross, it will continue to move back and forth across the

membrane to obtain an equilibrium.

• Once Equilibrium is reached the solute particles will still move across the membrane

but at equal rates in and out.

Gas Exchange

• What you think of as breathing in humans

• Organisms need to interact with the atmosphere

• Let out waste gases

• Take in gases

• Uses Diffusion

Types of Gas Exchange

• Plants

– Stomata

• Animals

– Gills

– Lungs

Gas Exchange in Plants (Stomata)

Gas Exchange in the Lungs

Check Yourself-Based on the direction the Oxygen is flowing on the below diagram, where is there a higher concentration of Oxygen?

A) In the Blood

B) In the Alveoli (Lungs)

All living things respond to a stimulus!

Living things respondto immediate and long-term changes in their environment (shiver when cold, change fur color, plants bend toward light)

Stimulus Response: Let’s Try It

• I will turn off the lights for a minute or two.

• Partner up and look at each other’s eyes.

• What happens when I flip the light back on?

• Why does this happen?

Other Examples: Responding to Stimuli

a. dogs pant when hot

b. grass smell is plants warning other plants they are getting cut

c. humans sweat when body gets too hot

d. reflexes – fight/flight

Homeostasis- a condition or process in which organisms use energy to keep conditions inside their cells constant or regular.

Why do you think this is important?

What levels in our body need to remain relatively the same?

Homeostasis

What would happen if our body temperature wasn’t constant?

What would happen in the amount of water or blood in our body wasn’t constant?

Amoeba Sisters: Homeostasis and Feedback

Negative Feedback: The body doesn’t like what is happening so it tries to oppose the effect of the stimulus.

**USED TO MAINTAIN HOMEOSTASIS**

Positive Feedback:Response enhances the effects of the original stimulus. **Contractions during childbirth

**Blood Clotting

Types of Responses

Negative Feedback: Thermoregulation

• Your body systems need to stay at a specific temperature to work properly

• If that temperatures changes the body tries to get back to its ideal temperature

Negative Feedback: Thermoregulation

Too Hot:-Sweating (Integumentary System)-Increased Blood Flow (Circulatory System)

Too Cold:-Shivering (Muscular System)

-Newborns can’t shiver until 6 months of age-Will limit blood flow to limbs

Negative Feedback: Blood Glucose (Sugar) Level

Too Much Sugar Pancreas Detects too

much sugar

Insulin is released

into blood

Liver and Muscle cells

take up glucose from

the blood

Blood glucose

is reduced

Blood Sugar is reduced

shutting down mechanism

Negative Feedback: Sugar Level too High

Homeostasis Set Point

Positive Feedback

Positive Feedback: Contractions During Child Birth

Pressure of Fetus on

the Uterine Wall

Nerve endings in the uterine

wall carry afferent messages

to the Hypothalamus

Production and Release

of Oxytocin into the

Blood

Increasing strength of

uterine contractions

Intensifies

The birth of the child will bring this process to a close.

Positive Feedback: Blood Clotting

**Technically blood clotting overall is a negative feedback since it is a response to try and stop a stimulus, but within that is a mini

positive feedback loop**

Harmful Effects of Positive Feedback

Fever

• can cause a positive feedback that pushes the body

temperature continually higher

• If the temperature reaches 45 degrees centigrade (113

degrees Fahrenheit) cellular proteins break down which

causes metabolism to stop and can lead to death

Positive and Negative Feedback Cartoon• You will create four total cartoons:

BIOLOGICAL EXAMPLES• One that shows how homeostasis is maintained by negative feedback loops

• One that shows how homeostasis is maintained by positive feedback loops

NON-BIOLOGICAL EXAMPLE (make it up)• One that shows how homeostasis is maintained by negative feedback loops

• One that shows how homeostasis is maintained by positive feedback loops

• You will be expected to use vocabulary from the unit

• Loops should be well explained

• You don’t have to be a great artist but it must show effort and be

colored and neat

• Due by the end of the period TOMORROW

• Worth 20 ASSESSMENT POINTS (5 points per cartoon)

• Should be stapled and turned in together

Positive and Negative Feedback Cartoon: Student Work Examples