Transcript Classification Notes

CLASSIFICATION
Why Do We Classify?
• We classify in order to
organize.
• We classify to
recognize
relationships among
organisms.
• We classify to study
the evolutionary
history of organisms
(phylogeny).
History of Classification
• Aristotle was a Greek
philosopher and
scholar.
• Divided organisms
into 2 groups - plants
and animals.
– Divided animals into
groups based on
number of legs.
– Divided animals into 3
groups according to
how they moved walking, flying, or
swimming (land, air, or
water)
History of Classification
• Carolus Linnaeus was a
Swedish scientist, who like
Aristotle, based his groupings
on similarities in appearance.
• Divided living things into one
of two "kingdoms" – Plant or
Animal.
• Divided each of the kingdoms
into smaller groups called
genera or “genus”.
• Divided each genus into
smaller groups called
"species“.
The Evolution of Our
Classification System
• The Linnaean System is used by scientists all over
the world, but has been expanded to include new
and different living things as they are discovered.
It will continue to grow as human knowledge
grows.
Classification Terminology
• CLASSIFICATION –
• Grouping things based on
their similarities.
• TAXONOMY –
• The science of classifying
organisms.
• ORGANISM –
• Any living thing.
• BINOMIAL
NOMENCLATURE –
• A two-part scientific name
(Genus species).
• EVOLUTION –
• Species change gradually
over time.
Our Current
Classification System
• The classification
system in use
today places each
living thing into a
series of specific
groups based on
similarities and
differences in body
structure, color,
behavior, etc.
Our Current
Classification System
• The largest group
into which any
living thing can be
classified is its
kingdom.
• This is followed by
its phylum, then its
class, order, family,
genus, and finally
its species.
The Kingdoms
• Most biologists use
a classification
system based on
five kingdoms.
The Kingdom Debate
• The number of
kingdoms is often
under debate,
depending on how
scientists interpret
current research.
• For example, some
scientists separate
the Moneran into
two kingdoms.
Our Hierarchical System
• Taxonomists divide
organisms into a
series of groups
(divisions) that get
more and more
specific.
• The most general
division of life is a
kingdom.
• The most specific
division of life is a
species.
Our Hierarchical System
• Within each kingdom, there
are groups, increasing in
commonality and
evolutionary relationships,
but decreasing in size (fewer
numbers).
• For example, two organisms
in the same order have more
in common than two
organisms in the same class.
Moneran Kingdom
• Bacteria are among the oldest living organisms
on Earth, and are very small.
• Bacteria can only be seen through a microscope.
• Bacteria are unicellular prokaryotes.
• Bacteria is commonly found in the ground, water
and in other living organisms.
• Most bacteria are
heterotrophs but some
are autotrophs.
Moneran Kingdom
• While some types
of bacteria can
cause diseases and
become harmful to
the environment,
animals and
humans, others
offer benefits that
we likely could not
live without.
Harmful Bacteria
• Some types of
bacteria can attack
plants, causing
diseases like leaf
spot and fire
blight.
Harmful Bacteria
• In human hosts, certain
types of bacteria can
cause diseases and
illnesses.
• Humans can be treated
with antibiotics, which
kill bacteria or at least
hamper their growth.
• Antiseptics, sterilization
and disinfectants can
help prevent
contamination and risk of
infection from bacteria.
Helpful Bacteria
• The term “friendly
bacteria” is used to
describe the types of
bacteria that offer some
benefit.
• Not only does bacteria
help produce the food we
eat and keeps the soil
fertile, it also helps us
digest our food.
• Bacteria in our digestive
system help to break
down protein and inhibit
the growth of potentially
harmful bacteria.
Archaebacteria vs. Eubacteria
• Archaebacteria
– “ancient bacteria”
– They survive in very
harsh environments
such as sea vents, hot
springs or boiling mud
around volcanoes.
– “extremophiles”
– All forms of
archaebacteria are nonpathogenic.
• Eubacteria
– “true bacteria”
– Most bacteria are in this
kingdom.
– They are the kinds
found everywhere and
the ones people are
most familiar with.
Archaebacteria vs. Eubacteria
Protozoan Kingdom
• This is sometimes called
the “odds and ends”
kingdom.
• unicellular
• Can be heterotrophic or
autotrophic.
• Most live in water
• ALL are eukaryotic
(have a nucleus).
Classification of Protists
• How they obtain nutrition
• How they move
• Animal-like Protists - protozoa
- heterotrophs
• Plantlike Protists - algae
autotrophs
• Fungus-like Protists –
heterotrophs & decomposers
Fungi Kingdom
• Mushrooms
• Molds
• Yeasts
• Mildews
Fungi Kingdom
• Most fungi are
multicellular (yeast
is unicellular).
• All fungi are
eukaryotic
heterotrophs.
• Fungi can be found
almost everywhere
on land, but only a
few live in fresh
water.
The Importance of Fungi
• Decomposers - breaking down dead
organic material cycling of
nutrients through the
environment.
• Provide numerous drugs (such as
penicillin)
• Food source - mushrooms, truffles
and morels
• Fermentation - cause the bubbles in
bread, champagne, and beer
• Yeasts, are important "model
organisms" for studying problems
in genetics and biology.
Bad Fungi?
• Humans
– ringworm
– athlete's foot
• Plants
– rusts
– Smuts
– leaf, root, and stem
rots
– damage to crops
Plant Kingdom
Plant Kingdom
• Plants are
multicellular
eukaryotes.
• Plants are autotrophs
and make their own
food through the
process of
photosynthesis.
• Plants feed almost all
of the heterotrophs on
Earth.
Animal Kingdom
Animal Kingdom
• All animals are
multicellular
eukaryotes.
• All animals are
heterotrophs.
• Animals have
adaptations that
allow them to find
food and digest it.
• Members of the
animal kingdom are
found in diverse
environments on
earth.
Invertebrates
Vertebrates
The Evolution of the
Animal Kingdom
The Organization of Life . . .
. . . ever changing!