Classifying Organisms
Classification Systems
Classification
• Classification: a way to organize living things into
similar groups.
• Scientists use cell type, cell structure, and DNA to
classify organisms.
• Domains and Kingdoms are the broadest levels.
Classification
•
•
•
•
•
•
•
•
•
Did King Phillip Come Over For Good Spaghetti?
Domain
Kingdom
Phylum
Class
Order
Family
Genus
species
Classification
• The three domains are Bacteria, Archaea, and
Eukarya, determined by cell structures.
• From here, domains are divided into 6 main
kingdoms.
• Bacteria  Bacteria
• Archaea  Archaea
• Eukarya  Animalia, Plantae, Fungi, and Protista
Classification
• Scientists use a system known as binomial
nomenclature to give organisms their scientific
names.
• This means “two names” and refers to an
organism’s genus and species.
• It was developed by Carolus Linnaeus.
• The Genus and species are also italicized. The
Genus will be capitalized, and the species will
have all lowercase letters.
Dichotomous Keys
• A dichotomous key is a chart with many choices
that guide you to the name of the thing you want
to identify.
• It can be used with anything, living or nonliving,
and can be made by anyone.
Classifying Organisms
Bacteria & Archaea
Domain: Bacteria
Kingdom: Bacteria
• There are more bacteria than
any other living thing.
• Can be found anywhere.
• Microscopic – very small
• Live on and in other living
organisms
Domain: Bacteria
Kingdom: Bacteria
•
•
•
•
Can cause disease and pollution
Used to make foods, like yogurt
Healthy bacteria helps us digest food
Classified based on shape, size, how they get
energy, and their oxygen use.
Domain: Archaea
Kingdom: Archaea
• Single-celled (unicellular)
• Live in extreme conditions
• Can live in water of high temps; some live using
energy from ammonia and sulfur gas
• Classified based on chemical structure/DNA
Classifying Organisms
Eukarya
Domain: Eukarya
Kingdom: Plantae
• 320,000 species
• Multicellular
• Get energy from sun
(photosynthesis)
• Classified based on structures and
how they use their structures to live;
also on how they reproduce.
Domain: Eukarya
Kingdom: Plantae
• Some have vascular tissue to transport materials
through the plant.
• Other plants absorb materials from their
surroundings.
• Some plants use seeds in cones, others use seeds
in fruit (flowers); some use spores.
Domain: Eukarya
Kingdom: Animalia
• Usually multicellular
• Consumers (cannot
make food)
• Usually divided into
two main groups:
vertebrates (with
backbones) and
invertebrates (without
backbones).
Domain: Eukarya
Kingdom: Animalia
• Vertebrates: only about 5% of animals.
• Fish: live in water; use gills for oxygen
• Amphibians: live part of their life in water and
part on land; they have smooth skin
• Reptiles: scaly skin; most live on land, some live
in water.
• Mammals: hair or fur covers body; drink milk
from mother
• Birds: most can fly; have feathers and wings.
Domain: Eukarya
Kingdom: Animalia
Domain: Eukarya
Kingdom: Animalia
• Invertebrates: about 95% of animals
• Sponges (Porifera), Jellyfish (Cnidarians), and
Earthworms (Annelida) are very simple.
• Mollusks: most have shells, but not all do; squid
and octopi are examples
• Echinoderms: live in salt water, body parts in
multiples of 5; sea stars
• Arthropods: segmented bodies; insects,
crustaceans, etc.
Domain: Eukarya
Kingdom: Animalia
Domain: Eukarya
Kingdom: Fungi
• Decomposers – feed on dead of decayed
materials.
• Yeasts, mushrooms, and mold are examples.
• Can be unicellular or multicellular
• Classified based on their size, shape, and how
they reproduce.
Domain: Eukarya
Kingdom: Protists
• Most diverse group in this domain.
• Most are unicellular, but some live in colonies
• Can take on characteristics of plants, animals, or
fungi.
• Plant-like use the sun for energy
• Animal-like are able to move and capture prey
• Fungus-like are decomposers
Domain: Eukarya
Kingdom: Protists
• Some don’t move at all; those that move do so in
a variety of ways, such as a whip-like tail
(flagella) or cilia
• Examples include Euglena, paramecium,
amoeba, and algae.