Faculty of Science, School of
Sciences, Natabua Campus
Lautoka
BIO509: Botany Introductory
Lecture: The Classification of
Plants and Other Organisms
LECTURER AND COURSE
COORDINATOR
Professor Anand Tyagi
Email:
[email protected]
Phone: 6667533 Ext 7020
LEARNING OBJECTIVE 1
•
Define taxonomy
•
Explain why the assignment of
a scientific name to each
species is important for
biologists
KEY TERMS
•
TAXONOMY
•
Science of describing,
naming, and classifying
organisms
Describing
Plants
Scientific Names
•
Biologists use scientific names
to precisely identify organisms
•
Each organism has only one
scientific name
• Avoids confusion of many
common names
LEARNING OBJECTIVE 2
•
Identify the biologist who
originated the binomial system
of nomenclature
•
Describe the general scheme of
the system
KEY TERMS
•
BINOMIAL NOMENCLATURE
• System for giving each
organism a two-word
scientific name
• First used consistently by
Carolus Linnaeus
Linnaeus
Binomial Nomenclature
Species
• The basic unit of
classification
• The scientific name of each
species has two parts:
• generic name (genus)
• specific epithet
•
Tradescantia virginiana
Species and Subspecies
A species is commonly
defined as the largest
group within which
interbreeding produces
viable offspring.
A sub-species is a
subgroup below the level
of a species. One definition
is a group which can
interbreed successfully
with other subspecies, but
does not do so in practice
(e.g. due to geographical
isolation).
Gilia latiflora
Gilia tenuiflora
subsp. excellens
subsp. davyi
subsp. latiflora
Fig. 18-4, p. 355
LEARNING OBJECTIVE 3
•
List and describe the
hierarchical groupings of
classification
Classification
•
Hierarchical groups (most to least inclusive)
• domain
• kingdom
• phylum
• class
• order
• family
• genus
• species
Classification of Ginger
Domain
Eukarya
Kingdom
Plantae
5 other
kingdoms
Phylum
Anthophyta
9 other phyla
Class
Monocotyledones
1 other main
class
Order
Zingiberales
18 other
orders
Family
Zingiberaceae
4 other
families
Zingiber
(ginger genus)
48 other
genera
Genus
Each taxonomic
level is more
inclusive than the
one below it. For
example, the
order
Zingiberales
consists
of 5 families. The
family
Zingiberaceae
contains 49
genera and a total
of about 1300
species.
A Dichotomous Key
A dichotomous key is a tool that allows the user to
determine the identity of items in the natural world, such
as trees, wildflowers.
Keys consist of a series of choices that lead the user to
the correct name of a given item.
LEARNING OBJECTIVE 4
•
Define systematics
•
Describe the cladistic
approach to systematics
KEY TERMS
•
SYSTEMATICS
•
•
Scientific study of the diversity
of organisms and their natural
(evolutionary) relationships
A systematist seeks to
reconstruct phylogeny
KEY TERMS
•
PHYLOGENY
•
•
Evolutionary history of a species
or other taxonomic group
MONOPHYLETIC
•
Said of a group consisting of
organisms that evolved from a
common ancestor
KEY TERMS
•
CLADISTICS
•
Classification of organisms
based on recency of common
ancestry rather than degree of
structural similarity
Cladistics
•
Cladists emphasize phylogeny by
focusing on when evolutionary
lineages (lines of descent) divide
into two branches
•
Cladists develop cladograms
KEY TERMS
•
CLADOGRAM
•
A diagram that illustrates
evolutionary relationships
based on the principles of
cladistics
Building a Cladogram
Characters
TAXON
VASCULAR TISSUES
SEEDS
FLOWERS
Moss
A
A
A
Fern
P
A
A
Pine
P
P
A
Daisy
P
P
P
Daisy
Pine
Moss
Fern
Node
1
Common ancestor
with vascular tissues
Common plant
ancestor
(a) All of the plant groups shown here except mosses
have vascular
Daisy
Pine
Moss
Fern
Node
2
Node
1
Common ancestor
with vascular tissues
Common plant
ancestor
(b) Seeds are a shared character for all plant groups
shown here except mosses and ferns.
Daisy
Pine
Moss
Fern
Node
3
Common
seedproducing
ancestor
Node
2
Node
1
Common ancestor
with vascular tissues
Common plant
ancestor
(c) Of the plant groups shown here, only the daisy
produces flowers.
Fig. 18-7c, p. 358
LEARNING OBJECTIVE 5
•
List and briefly describe the three
domains and six kingdoms recognized
by many biologists
KEY TERMS
•
DOMAIN BACTERIA
•
Domain of metabolically diverse, unicellular,
prokaryotic organisms
KEY TERMS
•
DOMAIN ARCHAEA
•
Domain of unicellular, prokaryotic organisms
adapted to extreme conditions (such as very
hot or very salty environments)
KEY TERMS
•
DOMAIN EUKARYA
•
Includes all eukaryotic organisms (protists,
plants, fungi, and animals)
The Three Domains
Domain
Bacteria
Domain
Archaea
Domain
Eukarya
Common ancestor
of all living organisms
Fig. 18-9, p. 360
Six-Kingdom Classification
•
•
•
•
•
•
Kingdom Bacteria (domain Bacteria)
Kingdom Archaea (domain Archaea)
Kingdom Protista (domain Eukarya)
Kingdom Fungi (domain Eukarya)
Kingdom Plantae (domain Eukarya)
Kingdom Animalia (domain Eukarya)
The Six Kingdoms
Bacteria
Archaea
Protista
Plantae
Protista
Animalia
Fungi
Common ancestor
of all eukaryotes
Common ancestor
of all living organisms
LEARNING OBJECTIVE 6
•
Summarize the scientific
limitations of the kingdom
Protista
KEY TERMS
•
PARAPHYLETIC
•
Said of a group consisting of
a common ancestor and
some, but not all, of its
descendants
Kingdom Protista
•
Ideally, all members of a kingdom
should have a common ancestor
•
Members of kingdom Protista are
paraphyletic
•
Some biologists think protists
should not be grouped in a single
kingdom
Animation: Constructing a
Cladogram
CLICK
TO PLAY
Courtesy: Thomson Higher education@2007
Questions are welcome?