Friday, April 19, 2013

Unit-3

Diversity of organisms


From the dawn of human civilization  people must have  began to identify  plants and animals and named them, because  their survival  was dependent on the use of plants and animals .

Species were identified  separately by their specific characters. 

Major groups of plants and animals  like grasses , fish , snakes  , birds were also identified  separately.

The names used were however varies depending on the language  of the people and the place . Biological study of organisms need a unified system of classification and nomenclature .

Aristotle was the first person who classified  organisms systematically .
Binomial nomenclature

With the advance of science and knowledge of biology different scientists, botanists and zoologists used different methods of naming and classification of organisms.Most often  polynomial system was used until eighteenth  century .

Carolous Linneus (1707-1778) proposed a binomial system of nomenclature of species which was accepted world wide.According to this name of an organism  has two parts .

First is the generic name and the second is specific epithet.

Generic name is usually a noun and specific epithet an adjective describing a particular feature.
Related species have the same generic name with different specific epithets.
Dipterocarpus  means fruit with two wings ,
zelanicus means endemic to Sri Lanka.

International codes of binomial nomenclature

Biologists have adopted sets of rules  or codes  of nomenclature.These codes are slightly  different for plants ,animals ,bacteria and viruses.Some of the important rules for naming plants ,fungi and animals are as follows.
  1. The species of organisms  cannot have the same name.
  2. Each species has a generic name and a specific name, both together  forming the species name or scientific name.
  3. Name should be made up of latinized words written in the Roman nscript.
  4. It should be underlined when hand written and italicized when printed.
  5. The first letter of the generic name must be capitalized and specific epithet must be in simple letters.
  6. A third word can be used to represent a subspecies or a variety.eg:Panthera pardus  kotiya -Sri Lankan leopard
  7. In scientific work  namr of the author who gave the name is indicated by  a capital letter, an abbreviation or full word at the end of the name , which is not latinised.eg; Cocus nucifera L  (L for Linnaeus}

Methods of natural and artificial classification

Arrangement of organisms into groups on the basis of the common characteristics  is called classification.Taxonomy is the science of classification.This includes  placing groups  of organisms in a hierarchichal order.

Two methods of classification

Artificial classification

Grouping is based on a few pre selected unifying characters .

The characters are selected first according to convenience and organisms are grouped based on the selected criteria.

Natural relationships are ignored

Only system used before eiteenth centuary.

Easy to used , easy to expand by adding more groups.

Natural Classification

Grouping is based on evolutionary relationships

Represents true natural relationships, based on phylogeny

Systems developed after study of evolution.

Based on many characters.

Characters used can be morphological ,anatomical, cytological or molecullar.

Most resently DNA and RNA sequences are being used .
Eg.Plants can be classified into Bryophyta, Lycophyta, pteridophyta,Coniferophyta, Anthophyta
Arthropods can be classified into Crustacea, Insecta, Chilopoda; Arachnida


Dichotomous key
A written dichotomous key presents the reader with two statements that describe certain characteristics. 

The statements should be mutually exclusive for the key to work efficiently. For example, 'it is either  or it isn't'.


 On selecting one, the reader is presented with the next couplet choice in the key and so on - to eventually arrive at an identification. .



How the key works[edit]

  1. Go to start
  2. Use choices given to arrive at the lowest possible level
  3. Organism is identified as much as possible

Example 1 :    Beetle, Honey Bee,  Butterfly, Ant 
               1.Possess wings .....................................2                                                                      Do not   possess wings .........................Ant 
        
              
               2.Having tranaparent wings...................3                                                                       Do not have   tranaparent wings .........Beetle                                            
              
               3.Possess hairs on appendages................Honey Bee
                  Do not possess hairs on appendages.....Butterfly        

Example2Snake  , Sea Anemone ,Butterfly, Earth worm ,Frog     

                1.Radially symetrical body ...........   Sea Anemone                                                      Not having symetrical body..........2
        
              
               2.Possess legs  ................... 3                                                                                         Donot possess legs.................  4                                                                         
              
               3.Havings wings...............Butterfly             
                  Do not have wings...............Frog

               4.Body covered by scales...............Snake
                   Body not covered by scales............Earth worm

Systems of classification

The early classification systems were all artificial systems.
 Mostly based on human uses.

Aristotle was the first to classify organisms scientifically. 

He divided organisms into  
plants 
animals 

Animals were further classified according to criteria such as
 mode of locomotion
 reproduction
 presence or absence of red blood cells.

Aristotle' s pupil Theophrastus 
classified plants according to habit 
 eg: Trees, Shurbs, Herbs and 
according to lifespaneg:annuals, biennials, perennials
 Upto the time of Linnaeus , scientists used many different methods.

Carolus Linnaeus (1753), Swedish botanist ,
 introduced binomial nomenclature and 

classified 6000 plants into a hierarchical order of taxa 
eg;    species
          genus
          order
          class

Classification of flowering plants  was based on the
number of stamens and 
styles of flowers

He identified two kingdoms  of organisms 
plants
animals

With the discovery of micro organisms ,

the scientists understood that there were organisms which could not be assigned into either plants or animals.

To get over this difficulty ,

Ernest Haeckel (1866) introduced a third  kingdom 
Protista

He also introduce the taxon phylum and
classified many organisms

With the discovery of electron microscope, 

Biologists identified two cellular organization,

 Prokaryotic

 Eukaryotic

Five kingdom  system of biological classification  was introduced by  
                                                Robert H.Whittaker-          
                                             
                                                   Monera
                                                   Protista
                                                   Fungi
                                                   Plantae
                                                   Animalia
His classification was based on the three criteria
1.cellular organization
2.unicellular or multi cellular nature
3.mode of nutrition

With the acceptance of Darwin's theory on evolution and 
unitary origin of life,

Taxonomists began to use of molecular methods in studying evolutionary relationships it became apparent that in the very early evolution, organisms had seperate into three stocks which are now called Domains

Carl Woese (1977)
classified organisms into three domains at a higher level over the kinhdoms 
Archaea
Bacteria
Eukarya

Hierarchy of taxa  from domain to species

In taxonomy each level of taxonomical hierarchy  is called a taxon  and each taxon has a rank and a name.
 eg: rank    name.
       class-  reptilia

Under the hierarchical system there are levels  of taxa.

Each domain divided into kingdoms

Kingdom is divided into phyla 

Phylum is divided into classes

Many of these categories may also be sbdivided

eg: sub family. sub species

From domain to species , the number of shared characters among the members in the taxa increases

From species to domain , the number of individuals  in the taxon increases 
                                     
                                 

Present system of classification and its basis

With the rapid advance  of molecular  biology new information on the evolutionary relationships  of organisms  are being collected rapidly.


  •  The sequance of bases of DNA   of important genes 
          DNA of mitochondria

          The base sequance of ribosomal RNA

          The sequance of amino acids in common proteins 

         Molecular structure of cellular components 
are used as important taxonomoic criteria in modern systematics.

As a result classification systems are changing rapidly.

The three Domain classification  suggested by Woese  is adapted here for the convenience.

It is very clear however Kingdom protista is not a natural group.

It is an artificial group including organisms which have different evolutionary origins

Viruses do not have cellular organization , therefore does not belong to any of the kingdoms.

It is also an artificial group considered seperately

 
Domain- Bacteria
                Archaea               
                Eukarya

                Kingdom  - Protista
                                    Fungi
                                    Plantae
                                    Animalia

Domain  - Bacteria

Cellular organization prokaryotic

Cell wall component peptidoglycan

Lipids in cell membrane are not branched

Sensitive to antibiotics

Protein synthesis begins with formyl methionine

One kind of RNA polymerase enzyme

Lives in many habitats
eg: 


 
Cyanobacteria            Purple bacteria                    Green Sulphur Bacteria 

Domain-Archaea

Cellular organization prokaryotic

Cell wall component lacks peptidoglycan, contains proteins and polysaccharides

Lipids in cell membrane have branched and chained structure

Not sensitive to antibiotics kike streptomycin and chloromphenicol

Protein synthesis begins with methinine

Several kinds of RNA ploymerase enzymes 

Lives in extreme environmental conditions such as volcanic pits , hot springs,salt marshes,deep sea

                                                       Methanococcus 
 Holobacterium
                     Thermcoccus Methanobacterium

Domian - Eukarya
Cellular organization eukaryotic

Cell wall component lacks peptidoglycan, contains polysaccharides

Lipids in cell membrane are not branched

Not sensitive to antibiotics

Protein synthesis begins with methionine

Several kinds of RNA polymerase enzymes

Lives in many different environmental conditions

eg; protists, fungi,plants , animals

Viruses






Viruses are neither prokaryotes nor eukaryotes and donot show any cellular organization

They range in size from 20nm - 300nm and they can be observed only by the use of electron microscope

Viruses are composed of a central core of nucleic acid and surrounded by aprotein coat called the capsid, which is made up of a fixed number  of protein molecules  called capsomeres

The nucleic acid may be DNA  or  RNA depending on the type of virus 

Most viruses that infect plants  have RNA 

Very few also have DNA.

Animal viruses include DNA - Herpes simplex or RNA - influensa
                                                                                              rabies virus
                                                                                              retro virus - HIV
Bacterial virus either include DNA or RNA

Protein coats of the viruses give them a characteristic symmetry. 

Onthis basis two morphological types are recognized

They are Icosa hedral  and
                      Helical


                
Some viruses have pollyphospholipid coats

eg: Retro virus

      Viruse' s posses an enzyme called reverse transcriptase which                     transcribes their RNA to  DNA  eg; HIV


Many viruses  cntain within the capsid one or more enzymes that are released  into the host cell  after the virus is uncoated

The most common enzymes are polymerases and they help in the replication of nucleic acids of viruses

A wide variety of of lipid components  have also been  found in viruses 
eg: phospholipids , glycolipids and fatty acids

Some viral envelopes contain with spikes made up of glycoprotein


Nature of viruses

Viruses are obligate parasites

They can live and reproduce only wth in  a metabolizing  host cell using protein synthesizing and energy generating  system of the cell

Viruses are widely distributed  in nature and also they can  infect other micro organisms

Since viruses are obligate parasites , cultivation of viruses  requires living cells eg; chick embryo

Sruses have complex structures
eg: bacterio phage


Reproduction of virus

The life cycle of bacterio phage

The life cycle of  plant viruses or animal viruses  are similar

Plant viruses enter plant  cells through surface wounds  or insects feeding on plant sap 






Characteristic features of bacteria
Prokaryotic organisms

Photoautotrophic, Chemoautotrophic or heterotrophic

Motile or non motile

Uni cellular or colony forming

Cell division is by transverse binary fission

Plasma membranes are made of different kinds of lipids

The cell walls are composed of peptidoglycan (carbohydrate + protein complex)

Ribosomal proteins and RNA polymerase are different  from those of eukaryotes

eg Coccus, Bacillus

Characteristic features of Cyanobacteria

Prokaryotic organisms

Photosynthetic

Most are unicellular. But some are linked to form filaments ,sheathed in mucous

Photosynthetic pigments are chlorophyll a, phycocyanin, Blue green in colour

Some have the ability of fixing nitrogen

eg: Lyngbia                                                                                  
  

Main characteristic features of  kingdom protista

Eukaryotic

Unicellular or multi cellular or colonial form

Photoautotrophic or heterotrophic

If cell wall is present it is made up of cellulose

Flagella, cilia or pseudopodia may be present

Phyla of kingdom protista

Ciliophora
Rhizopoda
Chrysophyta
Phaephyta
Rhodophyta
Chlorophyta

Characteristic features of phyla of kingdom protista

Ciliophora

Unicellular

Heterotrophic

Cilia as the locomotory organ

No cell wall

                                                                                                                                                                                                                                               Paramecium

Rhizopoda

Uni cellular

Heterotrophic

Pseudopodia for the locomotion

No cell wall

                                                                                                                                                                                                                                                                                                                                                    Amoeba
Chrysophyta

Uni cellular

Photoautotrophic.Ch a, Carotine, Fucoxanthin are the photosynthetic pigments

Reproductive cells have single flagella

Cell wall is made up of cellulose, pectin, mainly silica

Storage is chrysolaminarin                                                                                                        Diotoms                                                                                                                                                                                                                                                                                                                  

Phaeophyta

Multi cellular

Photoautotrophic.Ch. a,c, carotine, Fucoxanthin as photosynthetic pigments

Reproductive cells have flagella

Ceii wall is made up of cellulose. alginic acid

Storage food is lamnarin and manitol                                                                                        
                                                                                   Sargasum

Rhodophyta

Multi cellular

Photoautotrophic.Ch.a,d,Phycocyanin, Phycoerithrin as photosynthetic pigments

No flagella

Cell wall is made up of cellulose  and agar

Storage  is floridian starch                            Gelidium

Chlorophyta

Uni or multi cellular

Photoautotrophic

Vegetative cells and reproductive cells posses flagella

Cell wall is made up of cellulose and pectin

Storage  food is starch

                                                                                                           Chlamidomonas

Kingdom - Fungi

Eukaryotic

Unicellular or not

Truly multi cellular which form pypae

Saprophtic or parasitic or symbiotic

Cell wall is made up of chitin

Storage food is gycogen

A few are flagellated

Phyla of kingdom fungi

Chytridiomycota
Zygomycota
Ascomycota
Basidiomycota


Characteristic features of phyla of kingdom fungi

Chytridiomycota

  

Aquatic

Flagellated fungi, dichotomously branched hypae

Asexual reptoduction by zoospores

Sexual reproduction by motile male and female gametes
   eg: Allomyces

Zygomycota   


                                                                                            



Branched, multinucleated and aseptate mycelium

Asexual reproduction by spores within sporangium

Zygosporangium is produced in sexual reproduction

eg:Mucor



Ascomycota

  
    Branched, multinucleated and septate mycelium

Asexual reproduction by conidia , cut off by conidispores

Sexual reproduction by ascospores

eg:Aspergillus



Basidiomycota





Branched, monokaryotic or dikaryotic and septate mycelium

No. of sexual reproduction

Sexual reproduction by basidiospores

eg:Agaricus


Characteristic features of kingdom plantae

Eukaryotic

Multicellular

Photoautotrophic

Cell wall is mainly composed of cellulose

Main storage food is staech

Locomotory organ s absent but cilia or flagella may be found in gamates

Phyla of kingdom plantae

Bryophyta
Lycophyta
pterophyta
Cycadophyta
Coniferophyta
Anthophyta

Main characteristics of the phyla of kingdom plantae
Bryophyta

Especially common in moist places

No vascular tissue

Gametophytes are dominant and photosynthetic

Homosporous

 External water is necessary forfertilization

Seed plants

eg; Marchantia
       Mosses- Pogonatum

Lycophyta


Common in moist places

Sporophytesare dominant and gametophytes partially depend on sporophytes

Homosporous or heterosporous

External water is necessary for fertilization

Seed less plants

eg:Sellaginella

pterophyta

Terrestrial life adaptations are found

Vascular tissues are present

Sporophytes are dominant and photpsynthetic

Gametophytes depend on sporophytes

Heterosporous

External water is not necessary for fertilization

Seed bearing plants

Naked seed plants

eg; Nephrolepis
 Cycadophyta 

Terrestrial life adaptations are found

Vascular tissues are present

Sporophytes are dominant and photpsynthetic

Gametophytes depend on sporophytes

Heterosporous

External water is not necessary for fertilization

Seed bearing plants

Naked seed plants

eg: Cycas
Coniferophyta

Terrestrial life adaptations are found

Vascular tissues are present

Sporophytes are dominant and photpsynthetic

Gametophytes depend on sporophytes

Heterosporous

External water is not necessary for fertilization

Seed bearing plants

Naked seed plants

eg : Pinus
Anthophyta


Terrestrial life adaptations are found

Vascular tissues are present

Sporophytes are dominant and photpsynthetic

Gametophytes depend on sporophytes

Heterosporous

External water is not necessary for fertilization

Seed bearing plants

Seeds in fruits

Bear flowers as sexual reproducing unit

 eg: Flowering plants

Classes of phylum anthophyta

Monocotyledoneae
The embryo have only one cotyledonae

Fibrous root system

Parallel veins in leaves

Flower parts are trimerous

Perianth present in flowers( no distinct calyx/sepals and corolla/petals)

Number of xylem and phloem groups generally 12-20

Vacular bundles in the stem do not have cambia and are scattered
eg: grasses, coconut, paddy




Dicotyledonae

Embryo have two dicotyledonae

Tap root system

Reticulate veins in leaves

Flowers are pentamerous or tetramerous

Distinct calyx and corolla present in flowers

Number of xylem and phloem groups 5-6

Vascular bundles in the stem have cambia and arranged in a ring

eg: Rose, shoe flower




Characteristic features of kingdom Animalia

Eukaryotic

Multicellular

Heterotrophic

Cell wall absent

Special locomotory organs present such as cilia, flagella and contractile fibrils

Invertebrate phyla of kingdom animalia

Coelenterata
Platyhelminthes
Nematoda
Annelida
Mollusca
Arthropoda
Echnodermata

Main characteristics of the invertebrate phyla of kingdom animalia        
                

Coelenterata 

                  
1.Marine and fresh water                                                                           

2.Radial symetry   

                                   
3.Diploblastic                     



4.Mesoglia present                                                                                                       

5.Two types of body form
   Tube like polyps and  

   Umbrella shaped medusa

6.No segmentation

7.Cephalization absent

8.Nematocyst present in cell layer,
    No cuticle

9.Only corals posses exoskeleton, limy or horny

                                     
10.Incomplete alimentary canal, only mouth,                              
no anus
11.No circulatory system                                                          



12.No respiratory system


13.No excretory system     

14.Nerve net

15.Some with eyespots or statocyst as sensory organs

16.Simple reproductive system and  no  ducts

17.Asexual reproduction by budding or
      regeneration


18.Unisexual/bisexual

19.External fertilization

20.Planula larvae  can be seen  in the life cycle






Platyhelminthes


Free living forms inhabit warer or moist soil.Prasites live inside the host body

Bilateral symetry

Triptoblastic

No body cavity

Dorsoventrally flattened body

No segmentation

Shows a degree of cephalization

Epidermis soft and ciliated or covered by cuticle and with external suckers or hooks or both

Incomplete alimentary canal, only mouth, no anus


No circulatory system

No respiratory system

Flame cells  and ducts with  excretory system 





prence of a pair of anterior ganglia and longitudinal  nerve cords (1-3)



 Free living forms have eye spots /eyes

Some have chemoreceptors  in head as sensory receptors                                       
                                                       

         
Reproductive system with ducts and aditional organs



Asexual reproduction  in some forms by fragmentation

Usually bisexual

Internal fertilization

Many larval stages in parasitic forms .No larval stages in free living forms
 in the life cycle




Nematoda




Found everywhere in soil, water and as parasites

Bilateral symetry

Triploblastic

Pseudocoelomate



Slender, Cylindrical tapered end body.No segmentation 

Shows a degree of cephalization


Extra cellular  tough cuticle is present

Hydrostatic skeleton of pseudocoelomic  fluid

Lack cilia at any stage

Complete alimentary canal. Only mouth , no anus.

No circulatory system

No respiratory organs

Prence of simple excretory system with ducts

Prence of paired anterior ganglia  and a pair of lateral longitudinal  nerve cords

mainly papillae as sensory organs

A few have  paired reproductive system

No asexual reproduction or regeneration

Unisexual


Internal fertilization

Larval  parasites, larval stages in free living forms in the life cycle

Annelida


Found in world wide- marine, fresh water  or on/in soil

Bi lateral symmetry

Triloblastic

Well developed coelom

Cylindrical worm like body, internal and external segmentation

Advanced cephalization

Definite cuticle and chetae of chitin, arranged segmentally

Hydrostatic skeleton of coelomic fluid

Complete alimentary  having mouth and anus

Closed circulatory system with lateral hearts

Some have external gills

Excretory structures are nephridia

One pair of cerebral ganglia and  double, solid ventral nerve cord

Simple forms of eye

Asexual reproduction in some by budding or regeneration

 Reproductive system with sexual organs and ducts 

Unisexual or bisexual

External fertilization

Trochophore larvae  can be seen  in the life cycle

Mollusca




Mostly marine or fresh water, some are terrestrial

Bilateral symmetry

Triploblastic

Haemocoel

A little trace of segmentation 

Show a clear cephalization ,body  is divided into head, muscular foot, visceral mass

Body covering is soft and it forms a mantle

Many have exo skeleton.In some have endoskeleton

Complete alimentary canal having mouth and anus

Radulla in mouthOpen circulatory system with dorsal heart              

Gills or ctenidia in the mantle cavity for respiration

Excretory structures are nephridia

Nerve ring with ganglia and  two pairs of nerve cords

Sensory organs are eyes , tentacles, some have eye spots or statocysts 

Reproductive organs with ducts

Usually unisexual

External or internal fertilization

Trochophore or veliger larvae can be seen in the life cycle







Arthropoda









Lives in terretrial or aquatic environments


Bilateral symmetry

Triploblastic

Coelom greatly reduced and presence of  haemocoel

Externally jointed, segmented body.Each segment typically bears a pair of jointed appendages.

Distinct cephalization can be seen.Parts of body are head, thorax and abdomen.

Exoskeleton of chitin secreted by epidermis

Exoskeleton

Lacks cilia in any stage

Complete alimentory canal having mouth and anus

Mouth parts in mouth

Open circulatory system with dorsal heart


Gills or book lungs or  trachea as respiratory structures

Green glands or malphigian tubules  can be seen as excretory structures

Paired dorsal central ganglia and double  solid ventral  nerve cord

 Sensory organs are antennae,statocyst, sensory hairs, simple/ compound eyes

Reproductive system with reproductive organs and ducts

Asexual reproduction take place by parthenogenesis in some insects and crustaceans

Uni sexual

Mostly internal fertilization can be seen

One or more larval stages can be seen in the life cycle



Echinodermata




Exclusively marine

Adults are penta radial symmetry and larvae are bilateral symetry

Large coelom .It is developed as a water vascular system with associated tube feet

Cylindrical, star or flower form.No segmentation

No cephalization .Body is arranged in oral and aboral axis

Body covered by delicate epidermis often with spines

Prence of endoskeleton

Complete alimentary tract in some , some lack anus

Reduced circulatory system

Respiration by skin gills or papillae or tube feet or cloacal respiratory tree.

No excretory system

Radial nervous system present

Most donot have sensory organs.Some have tube feet for touch or sensivity. Some have eye spots or sensory tentacles as sensory organs

Have large reproductive  organs.

Uni sexual

External fertilization can be seen

Bipinnaria or dipleurula larvae  can be seen in the life cycle.




Vertebrates


Chordata



  • A rod like dorsal notochord present some developmental stge at least during part of the life cycle.
  • A single, dorsal hollow nverve cord  present some developmental stage  at least during part of the life cycle
  • Pharyn gill slits are present  at some developmental stage
  • Poat anal tail is present at least during the embryonic developmental stage
  • Closed circulatory system with a ventral heart.
  • Coelom well developed.
  • Sleleton if present, as an endoskeleton formed by mesoderm.
  • Sexes usually seperate , oviporous or viviporous









External features of organisms to identify their classes

Classes of phylum Coelenterata 

Hydrozoa
Dominant stage polyp which is solitary or colonial 
Medusa is small and free swimming

Radial symmetry

A circle of tentacles around mouth

eg:Hydra   




Obelia    


Soft coral

http://www.google.lk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&docid=LbBU2OOCiF4TtM&tbnid=wJ5tOvxTZJY0YM:&ved=0CAQQjB0&url=http%3A%2F%2Fwww.noaanews.noaa.gov%2Fstories2006%2Fs2652.htm&ei=qH41UuGeJIn7rAfU54CoDg&bvm=bv.52164340,d.bmk&psig=AFQjCNF1wPlZQFKvvi1kg9GrYN4EMsMDtg&ust=1379323130207017

Scyphozoa 

Dominant stage medusa which is free swimming ,                 
polyp stage is minute or lacking.                                         
                                  
Radadial symmetry

Four oral arms around mouth and tentacles like gastric filaments on the edge
eg: Aurelia              
              
                  
Anthozoa
Poplp stage only, which is solitary or colonial and no medusa.

Biradial symetry

Many tentacles around mouth in many rings

eg: Sea anemone
       




True coral



http://www.okc.cc.ok.us/biologylabs/Documents/Porifera_Cnidaria/Cnidaria.htm


Classes of phylum platihelminthes


Turbellaria

Free living

Leaf like body with head

Ventral mouth with reversible pharynx, no suckers

Ciliated epithelium with mucous glands

eg:Planaria,      

Dipalium



Trematoda

Endoparasite

Leaf like body without head

Ventral suckers on ventral side and anterior sucker surrounds mouth

Cuticle with spines

eg: Fasciola - liver flukes
Cestoda

Endoparasite

Slender, elongated, flat body divided into scolex and proglotids

Suckers and hooks on scolex

No mouth

Cuticle with microvilli

eg:Taenia - tape worm




Classes of phylum annelida



http://bio.rutgers.edu/~gb102/lab_2/301am-platyhel.html

Polychaeta         
Distinct head with eyes and tentacles
Presence of parapodia
Numerous setae
No clitellum

eg:Nereis

Oligochaeta

No distinct head
No parapodia
Fewer numbr of setae
Clitellium present

eg: earth worm

Hirudinea
No distinct head having anterior  and posteriot suckersNo parapodia
No setae
No clitelum

 eg:Leech

Classes of phylum Mollusca


Polyplachophora


Dorsal shell formed by 8 overlapping plates
Radula present
Large flat foot
Head is present without eyes or tentacles
Eye spots in some

eg:Chiton                                                 


Bivalvia
Shell of two lateral valves
No radula
Hatcher shaped foot
No head
No eyes
No tentacles
eg:Mussels                      

                                   
                                                      Oyster

Gastropoda

Univalved shell usually coiled.Sometimes shells are reduced.
Radula present.
Largely developed foot
Gead is present with tentacles and eyes .
Eyes onone pair of tentacles.

eg: Slug                       snail


Cephalopoda

External or internal shell  present or none
Radula present
foot is modofied into arms and siphon
Head is present conpicuous
Eyes and 8-10 arms or many tentecles and siphon are present.

eg: squid
            octopus                    


Classes of phylum Arthropoda
                                                                
                                       

Crustacea

Body is divided into cephalothorax and abdomen
One pair of appendages
Two pairs of antenna

eg:     prawn


                                                                                                                                                                                                          
         crab                                                                                                              
                                                                        

 Insecta

Head thorax and abdomen distinct
Three pairs of legs on thorax and two pairs of wings
One pair of antenna

eg:cockroach , any insect


Chilopoda

Head followed by numerous segments of body
One pair of legs per somite
One pair of antenna

eg: Centiped



Diplopoda
Head , short thorax and abdomen
Two pairs of legs per somite
One pair of antenna

eg: Millipeds



Arachnida
Prosoma -cephalothorax and abdomen - ophisthosoma
Four pairs of legs on cephalothorax
No antennae

eg:Scorpion, Spider,Ticks ,Mites
Classes of phylum Echinodermata

Asteroidea                                  
Consists of acentral disc and five tapering arms or ends
On the upper surface there are many blunt calcareous spines and pedicellaria
Mouth is locate in the lower surface- oral surface and arms are in the upper surface - aboral surface

eg:Star fish

                                            

Ophiuroidea                                

Small rounded disc wth five distinct arms which are long and fragile 
Long arms are jointed .
No pedicellaria.
Spines in lateral side of arm
Mouth is centered Mouth is centered.orally and no anus
Tube feet in two rows and no suckers

eg: Britle star
                                            
Echinoidea

No anus. Rounded or flat body
Skeleton eith movable spines and pedicellaria present
Mouth or anus either central or lateral
Slender tube feet with suckers

eg: sea urchin, sand dollar
         
                                           

      


  Holpthuroidea  

Elongated slender body
No spines or pedicellaria
Mouth anterior
Anus posterior
Tube feet usually present

eg: sea cucumber


Crinoidea
Bodi is a small cup shaped calyx of limy plates to which are attached five flexible arms.Some have stalks
Bearing many slender lateral pinnules
No spines
Mouth and anus on oral surface
Tentacles like tube feet

eg: Sea Lily


Classes of phylum chordata
Chondrichthyes                                                                                        


1.Spindle shaped body divided into head, trunk and tail

2.Skin with placoid scales

3.Paired pectoral and pelvic fins.Heterocercal caudal fin

4.Ventral mouth with emamelcapped teeth

5.Inner ear only,no middle or external ear

6.Cartilaginous skeleton 

7.Eyes ususlly well develloped without lids

8.Two chambered heart

9.Respiration by gills,several gill slits ,no opperculum

10.Excretion by metanephric kidney.

11.Major nitrogenous waste is urea

12.Body temperature ectothermal

13.Brain with ten pairs of cranial nerves

14.No larval stage,eggs produced, ovoparou or oviviviporous

15.Internal fertilization

eg:shark,skate

Osteichthyes

1.Spindle shaped  body divided into head , trunk and tail

2.Skin eith cycloid or ctenoid scales

3.Paired pectoral pelvic fin

4.Homocercal caudal fin

5.Usually terminal mouth with teeth which are bony

6.Inner ear only. no middle or external ear

7.Bony skeleton

8.Eyes normally well developed without lids

9.Two chambered heart

10.Four paired gill openings covered with opperculum

11.Major nitrogenous waste is ammonia

12.Body temperature ectothermal

13.Brain with ten pairs of cranial nerves

14.Larval stage may be present.Eggs produced usually oviporous

eg:    
    
Mullet   Carangids 
                           
Tuna





1.Body comprises head ,trunk and tail.

2.Soft skin with gland.

3.Paired pentadactyl limbs.

4.Some adults have tail.All larval forms have tails.

5.Ventral mouth.If teeth are present they are fasterned to the surface of bones.

6.Inner and middle ear only. No external ear.

7.Largely bony skeleton.

8.Eyes oftenly with movable lids and nictitating membrane.

 9.Three chambered heart.

10.Respiration by gills, lungs and  skin or mouth lining.

11.Excretion by metanephric kidney.Major nitrogenous waste is urea.

12.Body temperature ectothermal.

13.Brain  with ten pairs of cranial nerves.

14.Larval stage usually present.Eggs produced.( oviparous).

15.External or Internal fertilization.

eg: Toad, Frog,Salamander, Ichthyopus

Reptelia


1.Body is composed of head , neck  trunk and tail

2.Skin dry with horny scales and horny plates. 

3.Paired pentadactyl limbs.

4.Post anal tail covered with scales.

5.Long mouth margined with teeth in sockets in some reptiles.

6.No external ear. Inner and middle ear only. 

7.Well ossified skeleton.

8.Large  lateral eyes with eye lids  and with nictitating membrane.

9.Four chambered heart.

10.Respiration by lungs.

11.Excretion by metanephric kidney.

12.Excretion by metanephric kidney.Major nitrogenous waste is urea or   uric acid.

13.Body temperature ectothermal.

14.Brain with 12 pairs of cranial nerves.

15. No larval tage . Oviparous or ovoviviparous. Yolky eggs in shells.

16.Internal fertilization.

eg: lizard
       cobra
       crocodile
                                                                                                                             

                                                      
Aves

                                

 1. Stream lined body divided into head, neck trunk and tail.

2.Skin bears feathers .Legs have scales

3.Paired pentadactyl limbs.

4.Ventral mouth with teeth in sockets.

5.Absence of external ear,Presence of middle and internal ear. 
   .

6.Endo skeleton light,strong,fully ossified with air cavities.

7.Large and lateral eyes with eye lids and nictitating membrane.

8.Four chambered heart.

9.Respiration by lungs.

10.Excretion by metanephric kidnry,major nitrogenous waste is urea or uric acid.

11.Body temperature endothermal.

12.Brain with12 pairs of cranial nerves.

13.No larval stage.Yolky eggs in calcareous shells oviparous.

14.Internal fertilization.               

eg:parrot, crow
                                                                                              

Mammalia

1.Body with head,neck, trunk and tail. Differ in forms.

2.Skin bears hairs and glands.

3.Paired pentadactyl limbs.

4.Tails are of diverse forms.

5.Ventral mouth with teeth in sockets.

6.Presence of external, middle and inner ear.Presence of pinna. 

7.Skeleton largely of bone with cartilage over surfaces of joints.

8.Eyes with movable lids.Some have nictitating membrane.

9.Four chambered heart.

10.Respiration by lungs

11.Excretion by metanephric kidney.Major nitrogenous waste is urea or uric acid.

12.Body temperature endothermal.

13.Brain with 12 pairs of cranial nerves.

14.No larnal stage.Eggs develop within mother.(viviparous or oviparous.

15.Internal fertilization.

eg:Rat.Man
                                         
                                                                                             Photo by Dr. Lloyd Glenn Ingles © 2001 California Academy of Science 
quagga                                                                     
  Echidna.
             


                                     long-beaked echidnas                                     (short-beaked echidna)     
         Echidna
                                                                                                   . Photo by Dr. Lloyd Glenn Ingles © 2001 California Academy of Scienc                                                                                                                
                                                duck-billed platypus  

 spiny anteater 

                                                                               pouched-mammals                                                      

Red Kangaroo. Photo by Gerald and Buff Corsi, © 2002 California Academy of Sciences. <

                Red-necked Wallaby. Photo by Gerald and Buff Corsi, © 2002 California Academy of Sciences.

 

       Wombat. Photo © 2005 Sharon Chester.

 
 Koala.
Photo by Gerald and Buff Corsi, © 2002 California Academy of Sciences. <
                                                 Thylacinus, an extinct marsupial wolf.
   

                                                  


The bat
 Eptesicus fuscus. Dr. Lloyd Glenn Ingles, © 1999 California Academy of Sciences



                                                                                   Black Rat.
                                                                              Photo © 2004 Larry Jon Friesen. <


http://visual.merriam-webster.com/animal-kingdom/insectivorous-mammals.php

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