CLASSIFICATION
CHAPTER (15-4)
SC.912.L.15.4 : Describe how and why
organisms are hierarchically classified and
based on evolutionary relationship…HIGH
SC.912.L15.5 : Explain the reasons for changes
in how organisms are classified….HIGH
SC.912.L15.6 : Discuss distinguishing
characteristics of the domains and kingdoms of
living organisms…..MEDIUM
A. DOMAINS AND KINGDOMS
• A domain is a taxonomic category above the kingdom
level. It’s a new scheme that recognizes 3 domains: 2
domains of prokaryotes and 1 of eukaryotes.
• PROKARYOTES: 1.bacteria: differ from archea in cell
structure and chemical make up. Figure 16-8 p.361
• 2. archea: from Greek meaning “ancient”. Live in
xtreme environments, may resemble conditions in
early earth. Thermophiles, halophiles. Etc. p.361.
• EUKARYOTES: fungi, plants, animals, protozoans.
• 6 kingdoms vs. 5(old system) DRAW fig. 15-32. p.348
• 1. SYSTEM OF CLASSIFICATION: What is
taxonomy?? It is a branch of biology that
involves the naming and classification of
species. Assigning scientific names to species
is an important part of studying the history of
life. WHY?? Because common names can
cause confusions. Also, scientists around the
world can speak the same language and
understand each other.
2. REVIEW OF LINNAEAN SYSTEM OF CLASSIFICATION
AND BINOMIAL NOMENCLATURE.
• The system most widely used dates back to Swedish
Botanist Carolus Linnaeus (1707-1778). The system has
a 2 part Latin name ( BINOMIAL) for each species:
genus and species.
• The first part of the binomial name is the genus (plural
genera) to which species belong.
• The second part refers to ONE species within the
genus.
• Ex. Panthera pardus (leopard) Only the first letter of
the genus is capitalized and the whole binomial is
italicized
• Panthera leo ( Lion). Taxonomist place same genera
into families, similar families into orders, orders, etc
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Taxonomic classification of humans
Kingdom….Animalia
Phylum……Chordata
Sub-phylum…..Vertebrata
Class……Mammalia
Order…..Primates
Family…..Hominidae
Genus …..Homo
Species…..sapiens
DRAW FIGURE 15-24 PAGE 342
(you don’t have to draw the animal if you don’t want
to, but write the name instead)
• B. HIERARCHICAL CLASSIFICATION
• 1. CLASSIFICATION AND EVOLUTION. Darwin viewed
Linneaus’s system of classification in the context of
evolution. He wanted to show the relationship
between classification and evolution. A diagram that
reflects the hypothesis of evolutionary relationships
has a branching pattern called a PHYLOGENETIC
TREE. (phylogeny means evolutionary history).
• The greater the number of homologous structures 2
species have the more closely the species are
thought to be related.
• Example: The skull of chimpanzees and humans are
not single bones but a fusion of many bones. The 2
skulls match almost perfectly bone for bone. P.344
• DRAW FIGURE 15-25
• 2. MOLECULAR DATA AS A TAXONOMIC TOOL
• Relatedness of species can be measured by
comparing their genes and gene products (proteins).
The more the sequences math up the more closely
the species are related. A strong support for such
hypothesis is when the molecular data agrees with
other source such anatomy. Example; fossils and
molecular data coincide in explaining the relatedness
between hippos, cows, deer, whales and pigs.
• READ FIGURE 15-27
3. CLADISTICS
• Cladistics is the scientific search for ancestral
relationships between species and how they are
classified to demonstrate evolutionary commonship.
(clade = branch)
• Example: figure 15-28 (DRAW IT PLEASE). It shows
two simple cladograms which are phylogenetic trees.
IDENTIFYING CLADES
1. Each branch is a clade. It is like a taxonomic level in
classification and can exist within larger clades.
2. Example: figure 15-29..draw it plse!! Species B
through H are members of on clade (yellow).
Species I through K (orange). They are part of a
larger clade (blue). Species A is the ancestral
species.
• DERIVED CHARACTERS
• All of the organisms in particular clade share derived
characters (homologous characteristics that unite the
organisms as a group). DRAW FIGURE 15-30.
• Examples: HAIR: the horse, wolf, leopard, house cat.
• TEETH ADAPTED FOR EATING MEAT: wolf, leopard,
and the house cat.
• ABILITY TO RETRACT THEIR CLAWS: leopard and
house cat.
• C. WHY THESE CLASSIFICATIONS CHANGE?? P.346
REVIEW OF ANIMALS
A. Characteristics of Animals
• 1. Multicellular organisms: made of 2 or more cells. Ex.
Animals, plants, fungi and some protists.
• 2.Heterotrophic : organisms that do not make their own
food.
• 3. Eukaryotic: cells that have a membrane bound
nucleus. EX: Fungi, animals, plants, and protozoans.
• 4. Homeostasis: Read p.593. The ability of our bodies to
buffer changes in the external environment providing a
relative internal environment. This internal stability is
called homeostasis. Crucial due to our narrow range of
conditions. (CH27 SEC.3)
• Set points for example are normal levels at which our
bodies operate.
• The brain turns switches on and off that will maintain
homeostasis. Ex :shivering and sweating. Muscles
release heat when you are cold and sweating cools
the body.
• Also, hormones are released to help maintain
homeostasis.
• Excretion of body waste.
• ACTIVITY 27-3..IMPORTANT!!!
B. Evolutionary Body Plans**
• 1. Symmetry: a. radial symmetry, can be divided in
many planes ex. Hydra. (b). Asymmetry: sponges,
sessile organisms(not moving) no symmetry or
irregular shape. (c) bilateral symmetry: can be
divided down its length into similar right and left
halves. Can only be divided along one plain.
• 2. Germ layers: ectoderm, endoderm, mesoderm.
• From zygote to embryo (once cell division has
started) and in the early stages forms a blastula (5
days in humans) then a gastrula. Layers of cells lining
the outside are called ECTODERM cells. They develop
into the skin, and nervous tissue of the animal.
• ENDODERM cells will develop into the lining of the
digestive tract and organs associated with digestion.
. THE MESODERM cells is the third layer found between
the endoderm and ectoderm and they will develop into the
muscles, circulatory system, excretory system and in some
animals the respiratory system.
• 3. Body Cavity : fluid filled spaces inside their bodies in
which internal organs are found. It allowed animals to
grow larger because supports organ systems
• 4. Segmentation: is found in segmented worms.
Important adaptation for movement because every
segment has its own muscles allowing movement.
• 5. Cephalization: ex. Squid and actopi
• 6. Limbs: tetrapods, arthropods.
• C. Evolutionary Diversity
• 1. Invertebrates : Animals without a backbone. They
make up app. 95% of the different kinds of animals
on earth. Most live in aquatic or moist terrestrial
habitats. Most of the aquatic species live in marine
waters. Ex: sea stars, jellyfish, snails, clams, insects
and worms.
• 2. Vertebrates : animals with backbones, are well
represented in terrestrial habitats, but also live in
marine and freshwater. Ex. Fishes, frogs, snakes dogs,
ryan, michael, sarah, etc.
• DRAW FIGURE 17-20 PAGE 397. CHAPTER 17
SECTION 5
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