Topic 4 Biodiversity

� INTRODUCTION

There are various ways of dividing the living world into kingdoms. According to the five kingdoms recommended by the Institute of Biology UK, these five kingdoms are prokaryotae, protoctista, fungi, animalia and plantae. As the living organisms are diverse, a systematic classification is needed. This is based on the Linnaeus taxonomic hierarchy. Taxonomy is a hierarchical system for classifying and identifying organisms.

TTooppiicc

44 � Biodiversity

By the end of this topic, you should be able to:

1. Describe the classification of organisms according to LinnaeusÊbinomial system;

2. Explain the variety of living things and their characteristics in theanimal kingdom;

3. Identify the types of plants in the plant kingdom; and

4. Discuss the classifications of microorganism.

List three different organisms that you think would fairly represent each of the five kingdoms.

ACTIVITY 4.1

LEARNING OUTCOMES

� TOPIC 4 BIODIVERSITY 86

CLASSIFICATION OF ORGANISMS, ACCORDING TO LINNAEUS’ BINOMIAL SYSTEM

As there are enormous varieties of individual living things, biologists believe that classification is essential for our survival. The most popular classification is the bbinomial system devised by CCarolus Linnaeus. Each type of organism is given a name consisting of two words. The first word is the genus name, while the second is the species name. For example, the scientific name of paddy is Oryza sativa. Oryza is the genus name, while sativa is the species name. What is the importance of classification in biology? The importance can be explained as follows:

(a) To allow biologists to arrange massive data in a managed system;

(b) To assign unidentified organisms rapidly into the current system;

(c) To discover natural relationships among all classified organisms;

(d) To support the organic evolutionary theory of living organisms;

(e) To expand other related fields such as morphology, anatomy and physiology. Characteristics are derived from these fields in taxonomic works;

(f) To enrich the current taxonomic system. This is possible when new species are found;

(g) To prepare a systematic methodology for global living classification; and

(h) To aid ecologists in studying interactions among organisms efficiently. In addition to naming species, Linnaeus also grouped species into a hierarchy of categories. The base of the hierarchy is species. Species can be defined as a group of organisms that are morphologically and anatomically similar. In addition, they should be able to produce fit offspring. A few related species with close morphological and anatomical characters are grouped under the same genus. Likewise, a few related genera are to be grouped under a family. Following this, a few related families come under the same order and related orders under similar class. Next, phylum consists of a few related classes and related phyla are to be put under a kingdom. See Figure 4.1 on how a grizzly bear is classified.

4.1

TOPIC 4 BIODIVERSITY � 87

Figure 4.1: Hierarchical classification of the grizzly bear

Source: http://www.goldiesroom.org

In understanding the taxonomic hierarchy, the term „taxon‰ should be well-understood.

A ttaxon is a name for an organism in any level of the Linnaeus hierarchy system.


Category or hierarchy refers to each level of the hierarchical scheme. Examples of taxa are shown in Table 4.1.

Table 4.1: Taxonomy of Maize and Rat

Category or hierarchy Taxon

Maize Rat

Kingdom Plantae Animalia

Phylum Tracheophyta (Angiospermophyta)

Chordata

Class Angiospermae (Monocotyledoneae)

Mammalia

Order Glumiflorae Rodentia

Family Maydeae Muroideae

Genus Zea Rattus

Species Mays Rattus

From�Table�4.1,�we�can�extract�and�say�that�the�family�taxon�for�rat�is�Muroideae�and�Zea�is�the�genus�taxon�for�maize.��

ANIMAL KINGDOM

We have gone through how animals are classified, and learned how to recognise their taxonomy. Let us now continue our topic with the study of the aanimal kingdom, or kingdom Animalia (also known as Metazoa). See Figure 4.2 for some of the animals in this kingdom.

4.2

Referring to the Internet, answer the questions below. 1. Why do we need to put the binomial naming system or scientific

names in the italic form? 2. Instead of the italic form, is there any other way to represent those

words in the binomial naming system?

ACTIVITY 4.2


There are ttwo ttypes of animals, iinvertebrates and vvertebrates. Scientists estimated that 95% of the animal species found on this earth are invertebrates. Members of the animal kingdom have the following characteristics:

(a) Multicellular;

(b) Non-photosynthetic, feeding heterotrophically;

(c) Storage of excess carbohydrates as glycogen;

(d) Eukaryotic with no cell wall;

(e) Specialised tissues for movement and responses

(f) Most are sexually reproduced; and

(g) Nervous coordination, except for sponges.

Figure 4.2: Kingdom of Animalia Source: http://www.docstoc.com

We can discover a variety of living things in the animal kingdom – ranging from small to large animals. Listed below are some phyla to be introduced with examples in English and Malay language.

(a) Mollusca – Octopus (sotong kurita);

(b) Cnidaria – Jellyfish (obor-obor);

(c) Platyhelminthes – Tapeworm (cacing pita);

(d) Nematoda – Ringworm (cacing gelang);

(e) Annelida – Earthworm (cacing tanah);


(f) Arthropoda – Scorpion (kala jengking); includes insects, spider, crustaceans and mites;

(g) Echinodermata – Starfish (tapak sulaiman); and

(h) Chordata – Orang utan (orang utan); includes fish, amphibians, reptiles, birds and mammals.

�

PLANT KINGDOM

All the plants that grow around us are under the same kingdom, the pplant kingdom (or kkingdom Plantae). We are living in a tropical country and are surrounded by trees and grasses. See Figure 4.3 for some of the plants in this kingdom. There are ffour general characteristics of a plant:

(a) Eukaryotic;

(b) Cellulose cell walls;

(c) Multicellular; and

(d) Autotrophic (some cells contain chloroplasts and they feed by photosynthesis).

4.3

Look at the list below: Spider, butterfly, grasshopper and dragonfly. Which one do you think is not an insect?

SELF-CHECK 4.1


�Figure 4.3: Kingdom of Plantae

Source: http://www.docstoc.com

�In understanding plant biodiversity, you need to know that there are four phyla:

(a) Bryophyt – Mosses;

(b) Filicinophyta – Ferns (see Figure 4.4);

(c) Coniferophyta – Conifers; and

(d) Angiospermophyta – Flowering plants.

�Figure 4.4: Asexual non-motile spores underside of fern leaves


Table 4.2 shows some characteristics of the plant kingdom.

Table 4.2: Characteristics of Plants

Common Name Characteristic features

Mosses � Have no true stems or leaves, lack xylem and phloem; and

� The body is anchored in the substrate by rhizoids, not roots and have motile male gametes.

Ferns � The body has true leaves, stems and roots with an elaborate vascular system of xylem and phloem, small structure gamethophyte called prothallus;

� Coiled young leaves known as fiddleheads; and

� Produce asexual non-motile spores underside of leaves (see Figure 4.4) but can also reproduce sexually.

Conifers � Cone-bearing plants, no flowers and no fruits.

� Have needle-like leaves which are protected by a waxy cuticle; and

� Produce pollen for reproduction.

Flowering plants � True flowers, seed-bearing plants;

� Reproductive structures are carried within the flowers; and

� Fruits protect the seeds and help to disperse them efficiently.

�Some 250,000 species are Angiospermophyta phylla. It includes a wide variety of plants such as grasses, flowering shrubs and flowering trees. This phylla is so large that plants in it are divided into two classes:

(a) Monocotyledoneae (i.e. maize); and

(b) Dicotyledoneae (i.e. rose). Table 4.3 shows the different features of monocotyledoneae and dicotyledoneae.

Table 4.3: Features of Monocotyledoneae and Dicotyledoneae

Features Class Monocotyledoneae Class Dicotyledoneae

Embryo One cotyledon Two cotyledons

Leaf veins Usually parallel Branching

Flower parts Often in three Often five, four or more

Secondary growth

Never woody Woody


MICROORGANISM

Microorganism can be classified into five categories (see Figure 4.5).

�Figure 4.5: Categories of microorganisms

Each of these categories has its own features based on shape, size, reproduction, nutrition and habitat. (a) Bacteria Bacteria are small unicellular organisms. They are named by their shapes as

shown in Figure 4.6.

�Figure 4.6: Names of bacteria

�

4.4

List the differences between monocotyledoneae and dicotyledoneae.

SELF-CHECK 4.2


Table 4.4 gives you a list of bacteriaÊs features and their explanation. �

Table 4.4: Features of Bacteria

Feature Explanation

Shape � Different organisation cell: singular, pairs, bunches or chains;

� Motile with flagella (see Figure 4.7);

� No real nucleus, spread DNA within cytoplasm without enclosed membrane;

� Peptidoglican cell wall; and

� Some has thick outer cell wall called capsule.

Figure 4.7: Bacteria with flagella

Size � 0.1 �m to 10 �m.

Reproduction � Normally, asexual by binary fission. Offspring produced have same genetic materials (see Figure 4.8).

Figure 4.8: Asexual reproduction of bacteria


� Sexual reproduction is through conjugation in extreme environment (see Figure 4.9). However, it is continued by binary fission but the offspring have different genetic materials.

Figure 4.9: Sexual reproduction of bacteria (conjugation) Source: www.personal.psu.edu

Nutrition � Autotroph with chlorophyll can make their own food;

� Saprophyte find their food by decomposing dead organism; and

� Parasite get their food from living host.

Habitat � Almost everywhere.

(b) Fungi Fungi or moulds are multicellular microorganisms that produce spores (see

Figure 4.10).


�Figure 4.10: Moulds on bread

For further explanation on the features of fungi, letÊs take a look at Table 4.5.

Table 4.5: Features of Fungi

Feature Explanation

Shape � Various structures. Yeast is unicellular, while mushroom is multicellular;

� No chlorophyll, they feed saprotrophically; and

� Chitin cell wall.

Size � 10 �m to 100 �m.

Reproduction � Asexual (sometimes sexual) production of very large numbers of mini reproductive spores.

Nutrition � Thread-like structure; hyphae lie on or in the substrate for nutrient source.

Habitat � Soil, water, rotten fruit/vegetables and overdue bread.

For further reading on fungi, you can visit this website:

http://leavingbio.net/FUNGUS/Fungi2.htm. (c) Protozoa Most protozoa are motile unicellular microorganisms. Take a look at Figure

4.11 for examples of how protozoa looks like.


�� Figure 4.11: Protozoa

Table 4.6 offers explanations on the features of protozoa.

Table 4.6: Features of Protozoa

Feature Explanation

Shape � Constantly changing;

� Paramecium species move using cilia, euglena move using flagella, while ameoba move using their „fake‰ foot, pseudopodia. Plasmodium is an example of non-motile protozoa;

� Some protozoa have contractile vacuole for osmoregulation;

� Flexible thin cell membrane; and

� No cell wall.

Size � 5 �m to 250 �m.

Reproduction � Mostly asexual through binary fission or spores; and

� Some reproduce sexually through conjugation where meiosis took place (see Figure 4.12).


(d) VVirus Virus infects every type of living organism. Viruses by themselves are not

alive. They cannot grow or multiply on their own and need to enter living cells and take over the cells to help them multiply.

Figure 4.12: Conjugation of Paramecium caudatum

Nutrition � Protozoa with chlorophyll produce their own food, while the other with flagella, cilia or pesudopodia swim for their food (see Figure 4.13).

Figure 4.13: Phagocytosis process of feeding amoeba Source: www.britannica.com

Habitat � Watery area such as pond, river, intestine and blood vessel.


Bacteriophage virus (Figure 4.14) is not covered by membrane envelope, while influenza virus (Figure 4.15) is enclosed with envelope. Nucleic acid of bacteriophage contains DNA, while influenza virus contains RNA.

�Figure 4.14: Bacteriophage virus

�

Figure 4.15: Influenza virus

�


Table 4.7 explains the features of virus. �

Table 4.7: Features of Virus

�You can visit this website to see an animation of the HIV virus: http://www.sumanasinc.com/webcontent/animations/content/lifecyclehiv.html

Feature Explanation

Shape � Various shape;

� Tiny bundle of genetic material, either DNA or RNA, carried in a shell called the viral coat (capsid), which is made up of bits of protein. Some viruses have an additional layer around this coat called an envelope; and

� Lipid membrane covers the capsid. Many viruses do not have this envelope and are called naked viruses.

Size � 0.0006 �m to 0.4 �m (can only be seen through electron microscope).

Reproduction � The first step in a viral infection is the binding of a bacteriophage to a host protein. After binding, the chromosomes are fused within the host cell membrane and spread into the host cytoplasm. They will then replicate. When the host dies, the progeny bacteriophages are released (see Figure 4.16).

Figure 4.16: Bacteriophage life cycle

Nutrition � Parasite, get food from host.

Habitat � Living medium only.


(e) AAlgae � Algae�are�photosynthetic�organisms�that�occur�in�most�habitats.� Refer to Table 4.8 on features of algae.

Table 4.8: Features of Algae

Feature Explanation

Shape � Various shape; � Phytoplankton is unicellular while seaweed is multicellular; � Multicellular algae do not have true part like stem, leaves and root; � Presence of chlorophyll (green pigment) in green algae as well as

red and brown pigments in different algae (see Figure 4.17). � Motile algae glides or moves using their flagella � Cellulosed cell wall, slimy algae has pectin cell wall

Figure 4.17: Red, brown and green algae

Size � 1 �m to 60 m.

Reproduction � Depends on the surroundings. Normally, asexual through binary fission (see an example in Figure 4.18). In extreme surroundings, it mates sexually.

Figure 4.18: Spirogira elongated through binary fission

Nutrition � Autotroph because they have chlorophyll.

Habitat � Almost everywhere especially damp sites.


��

• The Linnaeus taxonomic hierarchy is used by taxonomists to organise organisms. The hierarchy goes down from kingdom to phylum, class, order, family, genus and lastly, to species.

1. In the table below, place a (�) if the feature is present or a (X) if the feature is absent for flagella, chlorophyll and spores.

Flagella Chlorophyll Spores

Bacteria

Viruses

Algae

Fungi

Protozoa

2. Look at the three pictures below and answer the questions that

follow. A B C

(a) Identify each type of bacterium from its shape.

(b) Which bacteria is motile? Give your reason.

(c) Give one way in which a bacterial cell wall differs from a plant cell wall.

(d) Which type of bacteria is used for making probiotic drinks like Vitagen and Nutrigen?

SELF-CHECK 4.3


• The five kingdoms of living things according to the Institute of Biology UK are prokaryotae, protoctista, animalia, plantae and fungi. Each kingdom has its own features or characteristics.

• Animals are divided into inveterbrates and veterbrates. • There are four general characteristics of plants: eukaryotic, cellulose cell

walls, multicellular and autotrophic. • Microorganisms can be classified into bacteria, protozoa, fungi, algae and

virus.

Algae

Angiospermophyta

Animalia

Annelida

Arthropoda

Autotroph

Bacteria

Bryophyta

Chlorophyll

Chordata

Cnidaria

Coniferophyta

Dicotyledoneae

Echinodermata

Filicinophyta

Fungi

Genus

Heterotroph

Kingdom

Linnaeus binomial system

Mollusca

Monocotyledoneae

Multicellular

Nematoda

Phylum/Phyla

Plantae

Platyhelminthes

Prokaryotae

Protoctista

Protozoa

Saprophytic

Species

Taxon

Unicellular

Virus


Brock, T. D., Brock, K. M., & Ward, D. M. (1989). Asas mikrobiologi dan penggunaannya. Kuala Lumpur: Dewan Bahasa dan Pustaka.

Kent, M. (2000). Advanced biology. New York: Oxford.

Lee Soon Ching & Liew Shee Leong. (2000). Biologi STPM Jilid 1. Kuala Lumpur: Penerbit Fajar Bakti Sdn Bhd.

Documents

Topic 4 Biodiversity