From the other day

1. What is a hypothesis?

2. What is the difference between a control and a variable?

3. After you gather and analyze data, you can form a ____________

4. What theory explains the diversity of the animals in the world (from the film)?

Characteristics of LifeAtoms, compounds, bonds

Mr DeGuzman

Dead or Alive?

• I am looking a something. How do I know it is alive?– Do I kick it around?– Do I talk to it?– How do I really know it is alive?

• What if someone said to you– “I’ll give you a million dollars if you can tell me

what defines things to be alive”– What would you say?

Characteristics of Life

• Scientists have come up with 5 “simplified” characteristics of life.– There are more characteristics but you will be

only responsible for 5.

Characteristics of Life

1. Made up of one or more cells

2. Reproduce

3. Grow and develop

4. Obtain energy

5. Respond to their environment

Made up of one or more cells

• All living things are made up of cells

• For example, – a bacteria is a single celled organism

(unicellular)– a human is a multi celled organism

(multicellular)– What about a virus like a cold?

Reproduce

• Organisms must reproduce to produce a new generation of organisms

• Two types of reproduction– “I need a mate” – sexual reproduction– “I split and make a copy” – asexual

reproduction

Grow and develop

• Living organisms go through stages of development

• Think about yourself– Do you still look the same way from birth?– Do other animals JUST appear?

Obtain and use energy

• Living organisms need energy to do work.

• Making complex substances from simple substances = anabolism

• Breaking down substance for energy = catabolism

• The balance between anabolism and catabolism is metabolism– Think about the food you eat and the energy

you release

Respond to their environment

• Anything that a living thing comes in contact is called a stimulus (stimuli)

• Imagine I – put a flame to your finger– wave a new Sprite Remix in your face– fart

• By keeping in balance with the environment, the living thing is in homeostasis

Review of the characteristics of life

1. Made up of one or more cells2. Reproduce3. Grow and develop4. Obtain energy5. Respond to their environment

• All must be true for something to be considered alive!

New characteristics of lifeCharacteristic ExamplesLiving things are made up of units called cells.Living things reproduce.

Living things are based on a universal genetic code.

Living things grow and develop.

Living things obtain and use materials and energy.

Living things respond to their environment.Living things maintain a stable internal environment.

Taken as a group, living things change over time.

Many microorganisms consist of only a single cell. Animals and trees are multicellular.Maple trees reproduce sexually. A hydra can reproduce asexually by budding.Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees.Flies begin life as eggs, then become maggots, and then become adult flies.Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat.

Leaves and stems of plants grow toward light.

Despite changes in the temperature of the environment, a robin maintains a constant body temperature.

Plants that live in the desert survive because they have become adapted to the conditions of the desert.

What’s the “matter”?

• Phases– Solid– Liquid– Gas

• Physical properties versus chemical properties– Think about burning paper

• What makes up all matter?

Atom

• Made up of 3 parts:

• Protons (positive)

• Neutrons (neutral)

• Electrons (negative)

• Atomic number– # of protons

• Atomic mass– # of protons + neutrons

Atoms versus Ions

• Atoms have equal amounts of protons and electrons– Therefore, the net charge is ZERO

• Ions have unequal amounts of protons and electrons– Therefore, it will have a net charge (+ or -)

Periodic Table

• A whole bunch of different elements

6

CCarbon12.011

Section 2-1

An Element in the Periodic Table

Go to Section:

Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14

6 electrons6 protons6 neutrons

6 electrons6 protons8 neutrons

6 electrons6 protons7 neutrons

Section 2-1

Figure 2-2 Isotopes of Carbon

Go to Section:

Bottom line

• Know the characteristics of life

• Know basic structure of atoms

• Atoms versus ions

• What is a isotope

• Next time:– Chemical Bonds– Water

Classwork – Life sign

• You are a vacationing on Mars• This is your first time on Mars and you

discover all these weird “living” things.• You want to tell your friends all about it• Create a sign of a “living” thing from Mars

– Make up a Martian “living” organism– Title or Name of organism– List and label how the animal can be

considered living (5 Characteristics of Life)– Color your Martian

Homework

• Martian Life poster

• Read Ch 2-1

• SA 2-1 all questions

• Read Ch 2-2

• Have a good day!