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 cells
2. Are based on a universal genetic code
3. Reproduce
4. Grow and develop
5. Respond to their environment
6. Maintain a stable internal environment
7. Taken as a group, evolve
8. 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
Cell- basic unit of all forms of life
CELLS
1. LIVING THINGS ARE MADE UP OF CELLS
(CONT)
Unicellular
Multicellular
Made of only 1 cell
 Must accomplish all
life activities within
one cell


Bacteria
(prok)
Euglena
(Euk)
Made up of more
than 1 cell
 Cells must work
together to
accomplish the
organism’s life
processes
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!
3. LIVING THINGS REPRODUCE (CONT)
TWO TYPES
OF
REPRODUCTION
Asexual
Involving a single
parent cell
 Offspring are
genetically
identical to the
parent
 Suitable for a stable
environment

Sexual
Involves joining 2
parent cells
 Offspring have
variations
compared to parents
and other offspring
 Suitable for a
changing
environment

3. LIVING THINGS REPRODUCE (CONT)
Examples:
Asexual
Typically
bacteria
(unicellular)
Less common but
possible in multicellular
organisms.

Sexual
Typical method for
animals, plants, some
fungi and protists.
Either method of reproduction has the
potential to be very successful - depending
on the species and its environment.
3. LIVING THINGS REPRODUCE (CONT)
4. LIVING THINGS GROW AND DEVELOP
• Both growth and development take place as an organism
matures.
• How would you differentiate between these 2 processes?
Growth

Getting Larger
Size
 Height
 Weight

Development

Changing Features

Ex: Butterfly life
cycle or Puberty
5. LIVING THINGS RESPOND TO THEIR
ENVIRONMENT

Stimulus


A signal to which and organism responds
Response

A specific reaction to a stimulus
5. LIVING THINGS RESPOND TO THEIR
ENVIRONMENT (CONT)
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)
What other examples can you think of?
Stimulus
Response
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 7.4
Various 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
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
a)

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)
Heterotrophs
(consumers)
Obtains food by
consuming other
living things
 Ex: Animals, fungi,
bacteria

Autotrophs
(producers)
Capture energy
from sunlight or
chemicals and use it
to produce their own
food
 Ex: All Plants,
bacteria

8. LIVING THINGS OBTAIN AND USE
MATERIALS & ENERGY (CONT)
 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)
Put the words “photosynthesis” and “cellular Respiration” in the correct
blank on the diagram.
8. LIVING THINGS OBTAIN AND USE
MATERIALS & ENERGY (CONT)
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)

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
ORGANISM
APPROX LIFESPAN
APPROX LIFESPAN
(years
(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 Insects
< 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

ORGANISMS
Taxonomy- The Science of Classification


OF
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
K P C O F G S
 Phylum
 Class
 Order
 Family
 Genus
 Species

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
Chelonia
Diptera
family
Hominidae Canidae
Emydidae
Culicidae
genus
Homo
Canis
Terrapene
Theobaldia
lupus
carolina
anulata
species sapiens
Carnivora
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 same
A. phylum
B. family
C. order
D. genus
Human
kingdo Animal
m
Wolf
Animal
phylum Chordata Chordata
Turtle
Mosquito
Animal
Animal
Chordata
Arthropoda
class
Mammalia Mammalia Reptilia
Insecta
order
Primates
Chelonia
Diptera
family
Hominidae Canidae
Emydidae
Culicidae
genus
Homo
Canis
Terrapene
Theobaldia
lupus
carolina
anulata
species sapiens
Carnivora
3.Two organisms classified in the same class could be in the same
A. genus
B. order
C. family
D. all of these
4.Of the following, Rana catesbiana is most closely related to
A. 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, is
A. species, genus, family, class, order
C. class, order, family, genus, species
B. 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.
Explain why someone would think viruses are
considered living things based on the 8
characteristics of life.
Influenza