7th Grade Science
http://www.bergoiata.org/fe/felins/10.htm
http://www.jonathanpmiller.com/intercalation/B-DNA.jpg
It’s Alive!! Or, Is It?
What Do You Think?
What characteristics do all living
things have in common?
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
There are Six Characteristics of
Living Things.
1. Living things have Cells.
2. Living things Sense and Respond to Change.
3. Living things have DNA.
4. Living things Reproduce.
5. Living things use Energy.
6. Living things Grow and Develop.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
• An object must
possess all 6 of the
characteristics in
order for it to be
considered a living
thing.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
1. Living Things Have Cells
•
•
•
•
Every living thing is made up of one or more
cells.
Cells are the simplest collection of matter
which has all the properties of life.
Some cells specialize to do specific jobs.
Examples are nerve cells, muscle cells,
etc…
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
2. Living Things Sense and Respond to
Change.
•
A stimulus is a change that causes the
activity of an organism to change.
• A stimulus can be internal (from inside).
– Examples are fever or vomiting when sick.
• A stimulus can be external (from outside).
– Example is squinting when the lights are
bright.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
2. Living Things Sense and Respond to
Change (cont…).
•
Homeostasis is the maintenance of a stable
internal environment.
- Our bodies are very good at controlling the
chemical reactions that keep us alive. These
reactions can only take place when conditions
are exactly right.
- Even though our outside conditions may
change, homeostasis keeps our internal
conditions the same.
- Example is body temperature.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
3. Living Things Have DNA.
•
•
•
DNA stands for deoxyribose nucleic acid.
DNA is the molecule that controls the
functions of a cell.
DNA is passed from parent to offspring.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
4. Living Things Reproduce.
•
•
•
Most living things reproduce by sexual
reproduction.
Sexual reproduction requires two parents that
produce offspring that share characteristics of
both parents.
Sexual reproduction produces more diverse
more diverse offspring.
Animals
http://www.jpbutler.com/thailand/images/elephant-and-baby.jpg
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
4. Living Things Reproduce (cont…).
•
•
•
Some things reproduce by asexual
reproduction.
Asexual reproduction occurs when a single
parent produces offspring that are exactly the
same as the parent.
This leads to more uniform offspring.
Hydra
http://universe-review.ca/I10-26-hydra.jpg
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
5. Living Things Use Energy
•
•
Metabolism is the total of all of the chemical
activities that the organisms performs.
Metabolism includes:
- Making food.
- Breaking down food.
- Building cells.
- Moving materials in and out of cells.
http://www.faculty.ucr.edu/~insects/systems/metabolism/metabolism.gif
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
6. Living Things Grow and Develop.
•
•
•
You grow as your body gets bigger.
Developing is the process of changing,
maturing, and going through different
stages.
Growing and developing depends on the
environment and the resources available.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
Visit the website below to
distinguish between Living
and Non-living things.
Ready?
Living and Non-living things
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
Let’s Review!
-1-
If the weather is cold outside,
how do you maintain your
body temperature?
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
Answer
• If it’s too cold, you will shiver to create heat.
Humans can add layers of clothes to keep
warm in the cold. Reptiles bask in the sun to
stay warm. Homeostasis allows us to do this.
http://www.utexas.edu/opa/news/02newsreleases/nr_200205/graphics/turtle2.jpg
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
Let’s Review
-2-
• What characteristics of living things does
a river have?
• Is a river alive?
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
Answer
• A river has energy (it moves) and can
grow larger (after rain), but it is not alive
because it is not made of cells, cannot
respond to stimuli, has no DNA, and
cannot reproduce.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
Websites to Visit
• Cells Alive
• Prokaryotes and Eukaryotes
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 1
It’s Alive!! Or, Is It?
What Do You Think?
What are several thing that are
necessary for living things to
survive?
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 2
It’s Alive!! Or, Is It?
• Food
• Water
• Air
• A place to live
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 7 : Section 2
The Cell in Action
Make a Venn diagram
comparing and contrasting
photosynthesis and cellular
respiration.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 8 : Section 2
Let’s Review!
-1Why are producers (who use
photosynthesis) important to
the survival of all other
organisms?
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 8 : Section 2
Answer
• Producers harness
energy in sunlight to
produce food
(glucose). This food
becomes an energy
source for producers
and for the organisms
that consume them.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 8 : Section 2
The Cell in Action
Websites to Visit
Good Diffusion Labs!
Transport In and Out of Cells
Photosynthesis
Cellular Respiration
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 8
The Cell in Action
Pre-AP Extensions for Chapter 8
There are 2 types of endocytosis. Each
process bring particles into the cell.
1. Pinocytosis
2. Phagocytosis
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 8 : Pre-AP
The Cell in Action
Pre-AP Extensions for Chapter 8
1. Pinocytosis involves ingesting small molecules
and/or fluids surrounding the cell.
• The cell membrane surrounds and “pinches
off” small droplets and places them in a vesicle
inside the cell.
• Most of the molecules are already dissolved in
a solution during pinocytosis.
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 8 : Pre-AP
The Cell in Action
Pre-AP Extensions for Chapter 8
Pinocytosis
•The small
molecules are
ingested by the
cell membrane
and used inside
the cell.
http://www.cat.cc.md.us/courses/bio141/lecguide/unit2/eustruct/pinocyt.html
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 8 : Pre-AP
The Cell in Action
Pre-AP Extensions for Chapter 8
The second type of endocytosis is called
phagocytosis.
• Phagocytosis is the process of surrounding,
engulfing, and digesting larger, microscopically
visible particles.
• Phagocytosis is used by most protozoans to get
food.
http://www.oum.ox.ac.uk/children/animals/protists.gif
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 8 : Pre-AP
The Cell in Action
Pre-AP Extensions for Chapter 8
Phagocytosis
•In phagocytosis, the
food particle is too big
to “absorb” through
the cell membrane. It
must be surrounded
and engulfed.
http://academic.brooklyn.cuny.edu/biology/bio4fv/page/phago.htm
© Fall 2005, Pflugerville ISD, 7th Grade
Unit 2 : Chapter 8 : Pre-AP