Classifying Life
Lesson 2
Think about your kitchen and
how it’s organized…
 List some reasons we organize our kitchens?
 Saves space
 Makes things easier to find
 Makes preparing food easier
Are kitchen items put in groups because of their
similarities or differences?
similarities
Grouping living things
 What do you think might be the best way to put
living things into groups?
 By their similarities
 What are some groups of living things?
 Animals, plants, fungi, protists, bacteria
How do scientists organize all
living things?
Scientists classify organisms according to how closely
they are related and to their similarities, such as
physical characteristics, how an organisms obtains
food or reproduces, where an organism lives, and
genetic information.
Activity Time!!!
 Let’s practice classifying certain items in our
classroom…OUR SHOES!
 Each person in the group will remove one shoe.
 The groups shoes will be placed in one pile.
 Groups will have 3 minutes to group together, or
classify, shoes by their similarities.
 Be prepared to explain to the class what
characteristics your group used to classify the
shoes.
How are organisms
classified?
 There are millions of different
organisms on Earth. Scientists
organize these organisms by
sorting, or classifying, them into
groups according to shared
characteristics.
Classification
Classification has been
called the science of finding
patterns. Classifying helps
scientists identify, study,
group, and name
organisms.
Classification System
 One classification systems used today
divides all organisms into 5 major groups
called kingdoms.
 The broadest group an organism is classified
into is a kingdom.
 Scientists classify organisms into kingdoms
by carefully comparing their cells, tissues,
organs, and organ systems.
Kingdoms
 Kingdoms are very broad groups.
 Do you think horses and spiders have much
in common?
 They don’t, but they are both included in the
animal kingdom.
 Smaller groups are needed to completely
classify an organism. 6 subgroups are used
to classify within kingdoms.
Subgroups
 Subgroups are:
 Phylum
 Class
 Order
 Family
 Genus
 Species
Species
 The narrowest group an organism can be classified
into is a species.
 A species contains only organisms that are very
closely related.
 A horse and a zebra share many traits, but they are
not similar enough to be the same species. A horse
and a pony are so similar that they are the same
species.
“Read a Chart”
 Is a horse more closely related to a spider or
a dog?
 A horse is more closely related to a dog
because they are both in the same class.
Spiders share only the same kingdom with
the horse and dog.
Why are smaller groups
necessary for classification?
 A large group, such as a kingdom,
contains too many organisms.
Smaller groups or similar
organisms are easier to study.
What makes organisms in the animal
kingdom different from organisms in the
other kingdom?
 All animals are multicellular. Plants and
animals are the only kingdoms that include
only multicellular organisms.
 Animals do not make their own food like
plants. They consume other organisms to get
energy.
 Animal cells do not have cell walls.
 Many animals are capable of moving from
place to place.
Animal kingdom
 One of the largest kingdoms!
 Features 9 phyla that belong to two major
groups:
 Vertebrate
 Invertebrate
Vertebrates
 A vertebrate is an animal with a backbone.
 Within the vertebrate group, there are 7
classes:





Amphibians
Reptiles
Birds
Mammals
And 3 classes of fish
Invertebrates
 An invertebrate is an animal without a
backbone.
 The phyla includes:
 Mollusks – clams and snails
 Echinoderms – sea stars, sea cucumbers,
and sea urchins
 Arthropods – Largest invertebrate
phylum. More arthropod species than
there are species in all the other animal
phyla. Includes insects, spiders, crabs,
and lobsters.
Review
 What is the broadest classification
group?
 Kingdom
 What is the narrowest group?
 Species
“Critical Thinking”
 Why do scientists use only the genus
and species names to identify an
organism and not all of the
classification groups?
 One possible reason would be that
using all the names would be
awkward.
Animal Kingdom
 What are some examples of organisms that
are animals?
 Fish, snake, cow, sponge, dragonfly, and
jellyfish.
 How are these animals alike?
 They move, eat food, and are made of many
cells.
 How are these animals different?
 One main difference is some have backbones
and some do not (vertebrates and
invertebrates).
How are animals different
from plants?
 Plants make their own food,
stay in one place, and have
different internal structures.
Which animal phylum
contains the most species?
 The arthropods have the most species
 Which contains the fewest species?
 The echinoderms have the fewest species.
Review
 How would you classify a dog and a butterfly?
 Dogs are vertebrates. They have backbones.
Butterflies are invertebrates. They do not have
backbones.
Critical Thinking
 An organism looks like an animal, but it does not
move. How could you determine if it is an animal?
 Look at the structure of its cells under a microscope.
You can conclude the organism is an animal if it is
made of animal cells.
Plant Kingdom
 The plant kingdom includes about
350,000 plant species. All plants are
multicellular and make their own food.
 Plants are organized into 2 major
groups:
 Vascular – contains tubes and vessels
 Nonvascular – do not have vascular
tissue
Vascular Plants
 Vascular plants have a system of vessels that run up
and down the body of the plant. Vascular tissue
carries water and nutrients up form the plants roots
to its leaves. It also move sugars made in the leaves
to other parts of the plant.
Nonvascular
Plants
 Nonvascular plants tend to
be much smaller than
vascular plants. They remain
small and close to the
ground where they soak up
water.
 Examples:
 Mosses
 Hornworts
 Liverworts
Fungus
Kingdom
 Fungi organisms include:
 Mushrooms
 Yeast
 Mold
Although most fungi are
multicellular, yeast are unicellular
fungi.
Fungi are different from plants.
They must get energy by breaking
down dead or decaying plants and
animals. They do not make their
own food.
Use of fungi
 Many fungi are used by humans.
 Yeast is used to make bread rise.
 Mold and yeast are also used to make some foods,
such as cheese.
 Some fungi are used to make medicine.
 Fungi can even grow on the human body!
What cell part is in the cells of
plants and fungi, but not
animals?
A cell wall
Which plant part is used to
classify plants into two main
groups?
The presence or absence of
vessels or tubes.
How are plants an fungi alike
and how are they different?
 Both plants and fungi have cell walls, do not
move from place to place, and do not have
true sense organs. Plants differ from fungi
because they can make their own food.
Fungi must obtain food from other
organisms.
What would happen to a
forest without fungi?
Dead organisms would be piled up
because they were not broken
down. The nutrients from onceliving material would not be
available to other organisms.
Bacteria and
Protists
 The simplest unicellular organisms have no nucleus. They are
divided into 2 kingdoms:
 Bacteria
 Archaea
 They do not have a nucleus.
 They do not have other organelles, such as mitochondria.
 Organisms in these kingdoms are found almost everywhere –
your toothbrush, food, your skin, and inside your body!
 Some bacteria cause diseases and infections (strep throat), but
many produce no harmful effects.
Bacteria and
Archaea
 Some bacteria and archaea are useful
and helpful to other organisms.
Cows cannot digest the grass they
eat without the help of archaea. The
archaea breaks down the grass that
the cow has stored in its stomach so
that it can be digested.
 We even need bacteria for digestion.
Bacteria is in your intestines and help
break down food. They also produce
vitamin K your body needs.
Protists
 The protist kingdom contains unicellular
and multicellular organisms. These can
either make their own food or eat other
organisms.
 Protists are larger than bacteria, but are
mostly microscopic.
 The cells of protists have a central nucleus
and other membrane-bound organelles.
 Protists have simple body structures and
lack specialized tissues.
 Protists include: algae, amoebas, and slime
molds.
Bacteria and Protists
 Bacteria are unicellular. Protists can be either unicellular or
multicellular.
 What structures are missing in bacteria cells?
 A nucleus and organelles
 How are bacteria different from archaea?
 Bacteria include germs and can be harmful. They are
everywhere. Archaea can be helpful and mostly live in harsh
environments.
How are protists different
from bacteria?
 Protists can make their own food or eat other
organisms. They are larger than bacteria and some,
but not all, are microscopic. The cells of protists also
have a nucleus and other membrane-bound
organelles.
Three main kinds of
protists
 Plant-like
 Animal-like
 Fungus-like
Viruses
 Viruses cannot be classified in any of the 6 kingdoms
because they do not carry out all of the basic life process.
 They are very small. They are smaller than bacterial cells.
 Some viruses are not harmful, but some enter the body of
an organism and cause it to get sick. The common cold,
chicken pox, polio, and HIV-AIDS are all caused by a
virus.
 Once inside the body, a virus attaches itself to a cell and
takes control of the cell’s activities. The cell gets filled
with the virus particles and bursts open releasing the
virus to invade other cells causing infection or disease.