5.5 CLASSIFICATION
Ms. TRS
ANIMALIA ( multicellular
heterotrophs)
FUNGI –eukaryotic,
multicellular ( except
yeast), saprotrophs
PLANTAE
(eukaryotic,
multicellular
autotrophs)
PROKARYOTA
( bacteria –
unicelluar
prokaryotic
,auto- or
heterotrophic
forms)
PROTOCTISTA – unicellular eukaryotic
heterotrophs with a few exceptions
5.5.1: Binomial system of
nomenclature
• Designed by Carolus Linneaus in 18th century
• Every species has a Latin name, made up of two
parts
• First part is the name of the Genus
• Second part specifies the species
• Name should be printed in italics (underlined if
hand written) and first part capitalized
• Example
• Humans are Homo sapiens
BINOMIAL SYSTEM OF NOMENCLATURE:
Two
named
First name =
capital letter;
if typed always
in italics; if
handwritten
always
underlined
Naming system
Homo sapiens
Developed by Carl
Linnaeus – a
Swedish Bottanist
(1707 – 1778)
Exam question:
Outline the binomial
system of nomenclature
(4)
GENUS
SPECIES
Answer:
Called binomial because two names are used;
First name is genus, with first name being a capital;
Second name is species, with no capital;
Italics are used when the name is printed;
The name is underlined if it is handwritten;
Discuss the value of classifying organisms
[2]
Species Classification - It is easier to find out which species an organism belongs to
when you have other organisms to compare it to;
You can make assumptions about characteristics of a species in general;
Evolutionary links, you can make assumptions about traits of a common ancestor;
You can also predict how they evolved.
Which of these two reef sharks are most closely related and why?
Carcharhinus
Perezi
Carcharhinus
melanopterus
Same genus,
different species
Triaenodon
Obesus
5.5.2: Hierarchical system of
classification
•
•
•
The Hierarchical system has seven levels called
taxons (plural: taxa)
Each taxon can contain one or more of the sub-group
below it
The seven level hierarchies of taxa are:
1.
2.
3.
4.
5.
6.
7.
Kingdom
Phylum
Class
Order
Family
Genus
Species
• To remember the taxa in the correct order:
• King Philip Came Over For Good Spagetti
Kingdom Animalia Plantae
Phylum
Chordata
Angiospermae
Class
Mammalia
Dicotyledoneae
Order
Primate
Rosales
Family
Hominidae
Papilionaceae
Genus
Homo
Pisum
species
sapiens
sativum
5.5.3: Distinguish between
Plant Phyla
• Kingdom: Plantae
• Characteristics:
•
•
•
•
•
Photosynthetic
Chlorophyll
Cellulose cell wall
Permanent vacuoles
Stores starch
• Classification of the major plant phyla is based on
external observable structures
• Main points: 1.roots, leaves and stems;
•
2. vascular tissue;
•
3. reproduction
4 Major plant phyla
Bryophyta –
Filicinophyta Coniferophyta Angiospermophyta
–
-
PLANTAE
Bryophyta
(mosses)
No roots or stem
Small leaf like structures,
rhizoids for roots
No vascular tissue
Reproduce using spores
Spores are formed in
capsules
Filicinophyta
(ferns)
Roots, leaves and
short stems
Leaves divided into
sections and curled
Coniferophyta
(conifers)
Woody trees
Have narrow needles for
leaves with thick waxy
cuticle
Have vascular tissue
Have vascular tissue
Reproduce using seeds in
Reproduce using
cones, not enclosed in
spores produced
fruits
under leaves
Wind pollinated
Angiospermophyta
(flowering plants)
Roots, leaves and stems,
stem can be woody
Have vascular tissue
Produce flowers
Seeds are enclosed in
ovaries that form fruits
Seeds dispersed through
fruits
Division Bryophyta
•No true roots, stem
or leaves
•Have rhizoids
instead of roots
•No vascular tissue –
must absorb water
from surface instead
of absorbing from
roots
•Reproduce by spores
made in capsules
•Moss are
commonly found
in damp, shady
areas
Filicinophyta (ferns)
• Have true roots, stem and
leaves. Stem not woody in
most of the plants
• First group of vascular
plants:
– Xylem and phloem
transport resources
between distant organs.
Reproduce by spores made
in sporangia under leave
Seen in tropical and
temperate forests
Coniferophyta
• Includes ~ 550 species of large trees
with thick woody stem including
pines, firs, spruces, and redwoods
• Most conifers have needles or
narrow leaves modified to prevent
water loss and thick waxy cuticle
• Have vascular tissue
• All produce seeds in cones
• Seeds are not enclosed in ovary or
fruit.
• Most use wind pollination for
reproduction.
• Almost all conifers are evergreens
Angiospemophyta
• True flowering plants
• Angion means “container,” –
seeds are enclosed in fruits.
During development, the
ovule becomes seed and
the ovary becomes fruit.
• Includes ~ 235,000 species
of flowering plants
• May rely on wind, birds,
insects, and even mammals
for pollination and
reproduction.
• Have vascular tissue
IB exam questions
Plants are a diverse group of eukaryotic organisms.
Describe the different characteristics of the
bryophyta, filicinophyta, coniferophyta and
angiospermophyta.
9 marks
Outline the structural differences that characterize
bryophytes, filicinophytes, coniferophytes and
angiospermophytes.
9 marks
Bryophyta:
No roots, have rhizoids, simple stem and leaves
Non vascular
Produce spores in capsule
Filicinophyta:
Have roots, stems and leaves, leaves are large and divided into sections
Have primitive vascular tissue
Reproduce by making spores in sporangia on the underside of leaves
Coniferophyta:
Have woody stem, narrow needle like leaves with thick waxy cuticle
Have well developed vascular tissue
Produce seeds in cones
Seeds are not enclosed in fruits
Angiospermophyta:
Produce flowers
Flowers have ovules in ovaries
Seeds are enclosed in fruits.( ovules form seeds and ovary forms fruit)
5.5.4 Distinguish between the major
invertebrate phyla using external features
Features of invertebrate phyla
Phylum
Porifera
Example:
Cnidaria
Example:
Platyhelminthes
Example
Annelida
Example:
Mollusca
Example:
Arthropoda
Example:
Symmetry
Digestive tract
Segmentation
Other features
Porifera
(sponges)
ANIMALIA
Invertebrates
Cnidaria
(jellyfish/coral
polyps)
Platyhelminths
(flatworms)
No symmetry
No mouth or anus
No segmentation
Water flows in and out of body through pores
Radial symmetry
Tentacles/ One opening to gut
No segmentation
Stinging cells - nematocysts
Bilateral symmetry
One opening to gut
No segmentation
Gas exchange over large surface area
Annelida
(segmented
worms)
Mollusca
Bilateral symmetry
D.T:With Mouth and anus
Very segmented
Bristles on body/
(snails/clams/
Usually bilateral/ no segmentation
octopuses)
DT: with Mouth and anus
Arthropoda
(insects/spiders/cru
staceans,
millipedes)
Most of them have a calcium shell
covering soft body
Bilateral symmetry
D.T : with Mouth and anus
segmented
Jointed legs + exoskeleton of chitin
Phylum Porifera
• Includes sponges
• Characteristics: no body symmetry, no tissues, no organs;
hermaphrodites; filter feeders; water moves in and out of the
body through pores; sessile
5.5.4
Phylum Cnidaria
• Includes corals, jellyfish, and sea anemone
• Characteristics: stinging cells for food and protection; one-way
digestive tract; radial symmetry; no segmentation drifters or
sessile
5.5.4
Phylum Platyhelminthes
• Includes flatworms like planaria, flukes, and
tapeworms.
• Characteristics: distinct head region (cephalization);
bilateral symmetry; most are parasites; one-way
digestive tract; no heart or lungs; flat shape - why?
5.5.4
Phylum Annelida
• Includes earthworms, marine worms, and leeches.
• Characteristics: segmented; bilaterally symmetrical;
well developed nervous, digestive, and circulatory
systems; two-way digestive system.
5.5.4
Phylum Mollusca
• Includes snails, clams, octopus and squids.
• Characteristics: bilateral symmetry; two-way digestive
tract; exoskeleton (shells) of calcium carbonate; soft
bodies; most are aquatic
5.5.4
Phylum Arthropoda
• Includes insects,
arachnids (spiders), and
crustaceans
• Characteristics of all
arthropods: exoskeleton
made of chitin; jointed
appendages; segmented
body; bilateral symmetry,
open circulatory system
• Molting – process of
shedding and
exoskeleton and growing
a new one to grow larger.
Dichotomous Key
• A dichotomous key is a method used to identify
organisms according to their physical traits based
on a system of answering yes or no questions
about an organism. Through a process of
elimination the organism is identified.
• Visible features are used
• Questions should be unambiguous
• Each question should divide the organisms into
two distinct groups
•
Identification game: http://www.scenicoregon.com/webanic/pages/animals.html
IB exam questions
• Which phylum does sponges belong to?
• What is the important feature of flat worms?