Transcript Classifying living things

Classifying living things
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Scientists develop system for classifying
living things.
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Scientists classify millions of species
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400 years ago organisms were classified on their
appearance and behavior
The problem with this is scientists have realized that
appearances can suggest false connections.
Many things helped change these classifications
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Observing
Collecting samples
The microscope
Classifying living things
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Classification and
Taxonomy
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Classification is the process
of arranging organisms into
groups based on similarities
Taxonomy is the science of
naming and classifying
organisms.
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A good system allows one to
organize a large amount of
information
so it is easy to find and
understand.
Classifying living things
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Using Classification
– Similarities and differences among
species are used
– Sometimes easy to see like fur, feathers,
or scales
– Others more detailed and require DNA
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Taxonomists study Biological
relationships
» The Greek word, taxis means
arrangement.
» Taxonomists are scientists who
classify and name organisms based
on their similarities and differences.
Classifying living things
– A Taxon is a group of organisms that share certain
traits.
– Taxons can be broad like animals and plants
– More specific like cats and roses.
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Taxonomists try to discover how one species
evolved as compared with another species.
Species sharing an ancestor are group together.
Classifying living things
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To determine how to classify, scientists compare
a variety of characteristics or traits
– A trait is a characteristic or behavior that can be used to
tell two species apart.
– IF two organisms share a trait, taxonomists try to
determine if they share the trait because they share an
ancestor.
Classifying living things
– Physical Evidence
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All physical evidence helps scientists see that all
living organisms are related by evolution
Primary tools used
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Color
Size
Weight
How group of organisms obtain energy.
The internal structure
And outward appearance
Comparing skeletons, and fossilized parts
Classifying living things
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Genetic Evidence
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In the mid 1950’s DNA
helped further classify
Genetic evidence
usually support
physical evidence, but
not always
Best example is the
red panda and Panda
bear
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Both ate bamboo,
Both look alike
except for size
DNA proved that the
red panda is more
related to the
raccoon family
Pandas more closely
to bears
Classifying living things
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Biologists use seven
levels of classification
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Carolus Linnaeus
developed both a naming
system and how to
organize them.
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Used appearance to group
This was called the
binomial nomenclature.
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Binomial means two
names
Nomenclature means list
of names
Most of these names are
Latin
Classifying living things
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Using scientific names
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He used both a genus and
species.
Certain rules for scientific
names must be followed
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First letter of the genus (which
comes first) is capitalized
Species’ first letter is
lowercase
Both written in italics
These two names are part of a
classification system that
contains several larger parts.
BINOMIAL NOMENCLATURE
• Uses two names
• A GENUS and A SPECIES
– Haliaeetus leucocephalus
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Genus is always CAPITALIZED
Species is always lower case
BOTH ARE IN ITALICS OR UNDERLINED
Just like us, each animal was given 2 names
Latin Binomials
• Canis latrans
– Coyote
• Canis lupis
– Timber Wolf
• Canis familiaris
– Domesticated Dog
Panthera leo
– Lion
• Panthera onca
– Jaguar
Classifying living things
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Classified into 7 groups
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Each group gets narrower
or specific then that last.
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Kingdom (most general)
(Animalia- the animals)
Phylum (Chordataanimals with a backbone)
Class ( Mammaliamammals or furry animals
that nurse their young.)
Classifying living things
– Order ( Carnivora- carnivores, or animals that kill and
each other animals)
– Family (Felidae- cat family)
– Genus( Felis housecats, cougars, and many others
– Species (catus- all housecats regardless of breed)
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Scientists can compare very broad categories,
As they go down the classification level, you get
more specific, eliminating organism that are not
longer similar.
Classifying living things
– Dichotomous keys and field guides help
identify
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A series of questions that can be answered in
only 2 ways
Your answer to each question leads to another
question with only 2 choices
The questions gradually narrow down the list of
possible organisms.
Field guides also help identify based on physical
characteristics.
Classifying living things
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Classification systems change as more
is learned.
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Taxonomy changes as discoveries are
made
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First there were 2 groups
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Plants
» Green
» Non-moving
Animals
Classifying living things
– Three Domains
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Grouping before placing
organism into Kingdoms
– Cells containing a nucleus are
called eukaryotic cells
– Cells with no nucleus called
prokaryotic cells
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The domain Bacteria and
Archae include ONLY
prokaryotic cells
Eukarya contain organisms
with eukaryotic.
Classifying living things
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Bacteria- class smaller then
Eukarya and have no nucleus
Archaea- Cells have a
distinctive chemistry and can
survive extreme environments.
Eukarya- larger and contain
more complex structures
Classifying living things
– Six Kingdoms
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After domains, all
organisms fall into one of
six kingdoms
– Plantae (includes plants,
trees, grass, and moss)
– Animalia (animals from lions
to bugs to Multicellular
microbes)
– Protista ( organisms that don’t
fit easily into animals, plant,
or fungi. Either unicellular or
have a simple Multicellular
structure)
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Fungi (mushrooms, molds and
yeasts)
Archaea ( organisms that are
similar to bacteria but have a
cell structure so different they
must fit in own kingdom)
Bacteria (unicellular with no
nucleus)
Changed around 1990 from 5
kingdoms.
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Chemical differences between
cells
Protista should be arranged into
smaller kingdoms because of
the many differences among its
species.
Classifying living things
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Two most familiar kingdoms
are plants and animals.
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Plantae
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250,000 plant species known on
Earth.
Tiny moss to giant kelp
All plants multicellular
All plants can make their own
food via photosynthesis
Can not move from place to
place
Can turn to face the sun or light
Grow upward
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Classifying living things
Animalia
– Already a million
species in the
kingdom
– More then 90 percent
are insects
– All animals get
energy from other
organisms
– Most have some type
of mouth and
– A nervous system
– Has no cell wall like
plants
Classifying living things
– Other organisms in
remaining 4 kingdoms
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Protista
– Has a wide variety of organism
– Most unicellular
– Have large complex cells with
true nucleus (eukaryote)
– Some eat other organisms
– Some can photosynthesize
– Do not have specialized cells
like plants, animals, or fungi
– Most live in fresh or salt water
Euglena sp.
Classifying living things
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Some organisms,
like seaweed are
also classified as
Protista
Fungi
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Composed of
molds, yeasts,
mushrooms
Take in nutrients
from their
surrounding
Remain rooted in
one place
Many fungi act as
decomposers
Don’t
photosynthesize
Classifying living things
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Archaea
– Mid 1990’s changed
classification of bacteria
– Do not have a nuclei
– But cell structure is different
from that of bacteria
– Live in water environments
– Live in extreme environments
like boiling mud near geysers,
Hot vents, bottom of oceans,
salt ponds, deep in sand
Classifying living things
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Bacteria
– Live just about
everywhere.
– Most are helpful
– Some harmful
– All unicellular
– Have small cells without a
nucleus
– Have a cell wall but not
the same as plants