Unit 1: Chemical Basis of Life

Unit 1A: Characteristics of Living Things

Biology is the scientific study of living things

Another word for a living thing is an organism.

Although the many types of organisms may appear to be different from one another, they all share common characteristics.

PART A- 8 IMPORTANT CHARACTERISTICS OF LIVING THINGS:

1. Are made up of cells2. Are based on a universal genetic code3. Reproduce 4. Grow and develop5. Respond to their environment6. Maintain a stable internal environment7. Taken as a group, evolve8. Obtain and use materials and energy

Can you think of a characteristic that living things and non-living things have in common? They are made up of ATOMS & MOLECULES

1. LIVING THINGS ARE MADE UP OF CELLS

Cell- basic unit of all forms of life

1. LIVING THINGS ARE MADE UP OF CELLS (CONT)

Made up of more than 1 cell

Cells must work together to accomplish the organism’s life processes

Made of only 1 cell Must accomplish all

life activities within one cell

Multicellular Unicellular

Euglena (Euk)

Bacteria (prok)

Clown Fish (Euk)

2. LIVING THINGS ARE BASED ON A UNIVERSAL GENETIC CODE

What is the genetic code of all organisms?DNA (deoxyribonucleic acid)

What does it do? Why is it an important necessary part of every cell? DNA is the genetic material of the cell

which contains codes for the building of proteins.

Proteins contribute to our traits!

2. LIVING THINGS ARE BASED ON A UNIVERSAL GENETIC CODE (CONT)

A segment of DNA that codes for a specific protein is called a gene

The reason different cells in the same organism can have a different structure and function even though they all have the same DNA (genes) is because different genes are being used in these different cells. A specific cell will have certain genes turned on while other genes are turned off.

3. LIVING THINGS REPRODUCE

The process of reproduction ensures that DNA is passed from parent(s) to offspring

Is reproduction necessary for the survival for the individual or the species?

Species!

TWO TYPES OF REPRODUCTION

Involving a single parent cell

Offspring are genetically identical to the parent

Suitable for a stable environment

Involves joining 2 parent cells

Offspring have variations compared to parents and other offspring

Suitable for a changing environment

Asexual Sexual

3. LIVING THINGS REPRODUCE (CONT)

Either method of reproduction has the potential to be very successful - depending on the species and its environment.

3. LIVING THINGS REPRODUCE (CONT)

Examples:

Asexual Sexual

Typically bacteria (unicellular)Less common but possible in multicellular organisms.

Typical method for animals, plants, some fungi and protists.

3. LIVING THINGS REPRODUCE (CONT)

4. LIVING THINGS GROW AND DEVELOP

Getting Larger Size Height Weight

Changing Features Ex: Butterfly life

cycle or Puberty

Growth Development

• Both growth and development take place as an organism matures.

• How would you differentiate between these 2 processes?

5. LIVING THINGS RESPOND TO THEIR ENVIRONMENT

Stimulus A signal to which and organism responds

Response A specific reaction to a stimulus

EXAMPLES: Directions: Label each of these examples - put an "S" by the stimulus and an "R" by the response:

a) When you touch something hot you pull your hand away.

b) A blowfish becomes larger and extends is spikes when it is threatened by a predator.

5. LIVING THINGS RESPOND TO THEIR ENVIRONMENT (CONT)

5. LIVING THINGS RESPOND TO THEIR ENVIRONMENT (CONT)

Stimulus Response

What other examples can you think of?

6. LIVING THINGS MAINTAIN A STABLE INTERNAL ENVIRONMENT

When organisms maintain relatively constant or stable internal conditions we call this homeostasis.

These conditions must be maintained within certain limits regardless of any internal or external changes.

Example: regulation of body temperature When its cold humans --- When its hot, we ---- We want to maintain our body temp around 98.6°F

6. LIVING THINGS MAINTAIN A STABLE INTERNAL ENVIRONMENT (CONT)

Another Example of Homeostasis:Blood pH should be around 7.4Various molecules called buffers work to

keep your blood at the correct pH

7. LIVING THINGS,TAKEN AS A GROUP, EVOLVE Evolution: Change of organisms over time Natural selection: the process by which

organisms that have traits that make them better able to survive in their environment will be more successful at reproducing and therefore pass these traits on to future generations.

7. LIVING THINGS, TAKEN AS A GROUP, EVOLVE (CONT)

What will happen to the population of these beetles over time? Why?

7. LIVING THINGS, TAKEN AS A GROUP, EVOLVE (CONT)

How do the new traits (variations) that are “selected for” by natural selection arise in organisms? (Where do these new traits or variations come from)?

Changes in the DNA (mutations) during reproduction can lead to adaptations in the offspring.

8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY

Materials and energy move between the living (biotic) and nonliving (abiotic) parts of the ecosystem

8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT)

Organisms must be able to a) Produce or obtain nutrients (like food and

water)b) Convert the nutrients into a usable form of

chemical energy called ATP c) Use these forms of energy to power their life

processes

All living things fit into one of two categories based on how they produce or obtain nutrients.

8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT)

Obtains food by consuming other living things

Ex: Animals, fungi, bacteria

Capture energy from sunlight or chemicals and use it to produce their own food

Ex: All Plants, bacteria

Heterotrophs (consumers)

Autotrophs (producers)

Photosynthesis is the process used by autotrophs to convert carbon dioxide and water into carbohydrates using energy from the sun.

What is the purpose of photosynthesis?To make food molecules

8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT)

The food is then used to build the structure of the organism and make cellular energy (ATP- energy that cells can use to power their processes).

8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT)

Cellular respiration Process that releases energy by breaking down

glucose and other food molecules in the presence of oxygen.

Cellular Respiration can be summarized by the following chemical equation:

What is the purpose of cellular respiration? To turn food molecules into ATP

IMPORTANT: All organisms undergo cellular respiration!

8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT)

8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT)

Put the words “photosynthesis” and “cellular Respiration” in the correct blank on the diagram.

HOW ARE PHOTOSYNTHESIS AND CELLULAR RESPIRATION RELATED????

The products of one reaction become the reactants of the other.

In other words, each reaction makes what the other reaction needs.

8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT)

8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT)

The combination of all of your chemical reactions is called your metabolism

When metabolism stops, An organism CANNOT

perform life functions DEATH

ONE LAST FEATURE OF LIVING THINGS

All living things must die

Life Span- How long an organism lives

ORGANISM APPROX LIFESPAN

(years)

ORGANISM APPROX LIFESPAN

(years

Bristlecone Pine 3,000-4,700 years Toad 36

Redwood 1,000-3,500 Deer 35

Douglas Fir 750 Cobra 28

Galapagos Tortoise 193 Tiger, Cat 25

Giant Tortoise 152 Bat 24

Box Turtle 123 Cow 22

Turkey Buzzard 118 Queen Ant, Chicken, Sheep 15

Swan 102 Tiger Salamander 11

Parrot 80 Green Frog 10

Eleplant 69 Hummingbird 8

Horned Owl 68 Queen Bee, Gerbil 5

Catfish 60 House Mouse, Hamster, Rat 4

Eagle 55 Most I nsects < 1year

Horse 50 Adult Honeybee Workers 6 weeks

WE CAN’T LIVE FOREVER!

Over time there is damage to DNA and cells

Cannot always maintain homeostasis in all environmental conditions

Earth has a limited supply of resources when organisms die the materials in their cells are recycled back into the environment for use by new generations of living things

PART B- CLASSIFICATION OF ORGANISMS

Taxonomy- The Science of Classification Involves grouping and naming organisms

Carolus Linnaeus-Binomial nomenclature- classification system in

which each species is assigned a two-part scientific name.

The first word is called the Genus. The second word is called the species (often

a descriptive word, such as a color or physical patterning).

Species: A group of similar organisms that can breed and

produce fertile offspring

Common Name Scientific Name

Daffodil Narcissus pseudonarcissus

Human Homo sapiens

Bullfrog Rana catesbiana

Green frog Rana clamitans

Leopard frog Rana pipiens

Linnaeus placed organisms into larger more general groups based on characteristics.

Linnaean Taxonomic Categories

The 7 major categories in classifying organisms, from most general to least general (most specific) are:

Kingdom Phylum Class Order Family Genus Species

K P C O F G S

Grizzly and Black Bear

Human Wolf Turtle Mosquito

kingdom Animal Animal Animal Animal

phylum Chordata Chordata Chordata Arthropoda

class Mammalia Mammalia Reptilia Insecta

order Primates Carnivora Chelonia Diptera

family Hominidae Canidae Emydidae Culicidae

genus Homo Canis Terrapene Theobaldia

species sapiens lupus carolina anulata

1.Of the following, the broadest (most general) classification category is

A. class B. phylum C. genus D. order

2.Two organisms classified in the same class must be in the sameA. phylum B. family C. order D. genus

Human Wolf Turtle Mosquito

kingdom

Animal Animal Animal Animal

phylum Chordata Chordata Chordata Arthropoda

class Mammalia Mammalia Reptilia Insecta

order Primates Carnivora Chelonia Diptera

family Hominidae Canidae Emydidae Culicidae

genus Homo Canis Terrapene Theobaldia

species sapiens lupus carolina anulata

3.Two organisms classified in the same class could be in the sameA. genus B. order C. family D. all of these

 4.Of the following, Rana catesbiana is most closely related toA. Rana pipiens B.Homo sapiens C.Xenopus laevis D. Felis domesticus 5.Of the following, the correct order from largest, most general group, to smallest, most specific group, isA. species, genus, family, class, order C. class, order, family, genus, speciesB. species, family, genus, class, order D. class, genus, order, family, species

6 Kingdoms of Living Things

VIRUSES: ALIVE or NOT?

There is some debate over whether viruses are living or nonliving. Most agree that they are nonliving. Why?

They are unable to INDEPENDENTLY carry out all life processes

They are particles made of DNA & proteins that can replicate only by infecting living cells.

Do not belong to any kingdom and don't contain any cells.

Influenza

Explain why someone would think viruses are considered living things based on the 8 characteristics of life.