are worm-like parasites. The clinically relevant groups are separated according to their general external shape and the host organ they inhabit. There are both hermaphroditic and bisexual species.
The definitive classification is based on the external and internal morphology of egg, larval, and adult stages.
Helminth is a general term meaning worm. The helminths are invertebrates characterized by elongated, flat or round bodies.
In flatworms or platyhelminths (platy from the Greek root meaning “flat”) include flukes and tapeworms.
Roundworms are nematodes (nemato from the Greek root meaning “thread”).
ORIGIN OF CHORDATES
Animal kingdom is basically divided into two sub kingdoms:
Non-chordata- including animals without notochord.
Chordata- This comprising animals having notochord or chorda dorsalis.
Chordates were evolved sometime 500 million years ago during Cambrian period (invertebrates were also began to evolve in this period) .
Chamberlain (1900) pointed out that all modern chordates possess glomerular kidneys that are designed to remove excess water from body.
It is believed that Chordates have originated from invertebrates.
It is difficult to determine from which invertebrate group the chordates were developed.
Chordate ancestors were soft bodied animals. Hence they were not preserved as Fossils.
However, early fossils of chordates have all been recovered from marine sediments and even modern protochordates are all marine forms.
Also glomerular kidneys are also found in some marine forms such as myxinoids and sharks. That makes the marine origin of chordates more believable.
Chordates evolved from some deuterostome ancestor (echinoderms, hemichordates, pogonophorans etc.) as they have similarities in embryonic development, type of coelom and larval stages.
Many theories infers origin of chordates, hemichordates and echinoderms from a common ancestor.
are worm-like parasites. The clinically relevant groups are separated according to their general external shape and the host organ they inhabit. There are both hermaphroditic and bisexual species.
The definitive classification is based on the external and internal morphology of egg, larval, and adult stages.
Helminth is a general term meaning worm. The helminths are invertebrates characterized by elongated, flat or round bodies.
In flatworms or platyhelminths (platy from the Greek root meaning “flat”) include flukes and tapeworms.
Roundworms are nematodes (nemato from the Greek root meaning “thread”).
ORIGIN OF CHORDATES
Animal kingdom is basically divided into two sub kingdoms:
Non-chordata- including animals without notochord.
Chordata- This comprising animals having notochord or chorda dorsalis.
Chordates were evolved sometime 500 million years ago during Cambrian period (invertebrates were also began to evolve in this period) .
Chamberlain (1900) pointed out that all modern chordates possess glomerular kidneys that are designed to remove excess water from body.
It is believed that Chordates have originated from invertebrates.
It is difficult to determine from which invertebrate group the chordates were developed.
Chordate ancestors were soft bodied animals. Hence they were not preserved as Fossils.
However, early fossils of chordates have all been recovered from marine sediments and even modern protochordates are all marine forms.
Also glomerular kidneys are also found in some marine forms such as myxinoids and sharks. That makes the marine origin of chordates more believable.
Chordates evolved from some deuterostome ancestor (echinoderms, hemichordates, pogonophorans etc.) as they have similarities in embryonic development, type of coelom and larval stages.
Many theories infers origin of chordates, hemichordates and echinoderms from a common ancestor.
DENTITION IN MAMMALS
The study of arrangement structure and number of types of teeth collectively is called as dentition. Teeth are present in the foetal as well as in adults of mammals, based on the presence of teeth Mammals are two types.
Edentata : In some animals teeth are absent hence called as edentate. e.g., Echidna or spiny ant-eater (Tachyglossus) the teeth are absent in all stages of life.
Dentata : Teeth are present in all mammals though a secon¬dary toothless condition is found in some mammals. Modern turtles and birds lack teeth. The adult platypus (Ornithorhynchus) bears epidermal teeth but no true teeth are present. In platypus embryonic teeth are replaced by horny epidermal teeth in adult.
Classification According to the Shape and Size of the Teeth:
Homodont:
Homodont or Isodont type of teeth is a condition where the teeth are all alike in their shape and size in the toothed whales e.g., Pinnipedians. Fishes, amphibians, reptiles and in the extinct toothed birds.
Heterodont
Heterodont condition is the usual feature in mammals, i.e. the teeth are distinguished according to their shape, size and function. The function is also different at different parts of the tooth row.
According to the Mode of Attachment of Teeth:
Thecodont : The teeth are lodged in bony sockets or alveoli of the jaw bone and capillaries and nerves enter the pulp cavity through the open tips of the hollow roots e.g., mammals, crocodiles and in some fishes.
Acrodont: The teeth are fused to the surface of the underlying jawbone. They have no roots and are attached to the edge of the jawbone by fibrous membrane e.g., fishes, amphibians and some reptiles.
Pleurodont:
The teeth are attached to the inner-side of the jawbone. The tooth touches the bone only with the outer surface of its root. In acrodont and pleurodont types of dentition, there are no roots, and nerves and blood vessels do not enter the pulp cavity at the base, e.g., Necturus (Amphibia) and some reptiles.
According to the Succession or Replace¬ment of Teeth:
It discusses basic information regarding a hemichordate animal called Balanoglossus or Acorn worm, which is also a good connecting link between the non-chordates and chordates.
Sponges,are pore bearing,multicellular,diploblastic animals that belong to phylum Porifera
Body of all sponges is perforated by large number of pores called ostia through which water enters Inside body and flows through a system of criss-crossing canals known as canal system
Three main types of canal systems in the order of increasing complexity are Asconoid, Syconoid and Leuconoid type.
paramecium is a microscopic organism. it is an protozoan that comes under ciliates. they are even visible under naked eyes. Paramecium are unicellular organism they lives in aquatic environment. they are used as live feed for fishes.
Chordata is the last phylum of kingdom Animalia.
Which is further subdivided into subphylums, divisions and classes.
The Slides shows the classification of the phylum along with the basis on which it is classified.
(includes examples along with pictures for easy understanding and memorizing)
DENTITION IN MAMMALS
The study of arrangement structure and number of types of teeth collectively is called as dentition. Teeth are present in the foetal as well as in adults of mammals, based on the presence of teeth Mammals are two types.
Edentata : In some animals teeth are absent hence called as edentate. e.g., Echidna or spiny ant-eater (Tachyglossus) the teeth are absent in all stages of life.
Dentata : Teeth are present in all mammals though a secon¬dary toothless condition is found in some mammals. Modern turtles and birds lack teeth. The adult platypus (Ornithorhynchus) bears epidermal teeth but no true teeth are present. In platypus embryonic teeth are replaced by horny epidermal teeth in adult.
Classification According to the Shape and Size of the Teeth:
Homodont:
Homodont or Isodont type of teeth is a condition where the teeth are all alike in their shape and size in the toothed whales e.g., Pinnipedians. Fishes, amphibians, reptiles and in the extinct toothed birds.
Heterodont
Heterodont condition is the usual feature in mammals, i.e. the teeth are distinguished according to their shape, size and function. The function is also different at different parts of the tooth row.
According to the Mode of Attachment of Teeth:
Thecodont : The teeth are lodged in bony sockets or alveoli of the jaw bone and capillaries and nerves enter the pulp cavity through the open tips of the hollow roots e.g., mammals, crocodiles and in some fishes.
Acrodont: The teeth are fused to the surface of the underlying jawbone. They have no roots and are attached to the edge of the jawbone by fibrous membrane e.g., fishes, amphibians and some reptiles.
Pleurodont:
The teeth are attached to the inner-side of the jawbone. The tooth touches the bone only with the outer surface of its root. In acrodont and pleurodont types of dentition, there are no roots, and nerves and blood vessels do not enter the pulp cavity at the base, e.g., Necturus (Amphibia) and some reptiles.
According to the Succession or Replace¬ment of Teeth:
It discusses basic information regarding a hemichordate animal called Balanoglossus or Acorn worm, which is also a good connecting link between the non-chordates and chordates.
Sponges,are pore bearing,multicellular,diploblastic animals that belong to phylum Porifera
Body of all sponges is perforated by large number of pores called ostia through which water enters Inside body and flows through a system of criss-crossing canals known as canal system
Three main types of canal systems in the order of increasing complexity are Asconoid, Syconoid and Leuconoid type.
paramecium is a microscopic organism. it is an protozoan that comes under ciliates. they are even visible under naked eyes. Paramecium are unicellular organism they lives in aquatic environment. they are used as live feed for fishes.
Chordata is the last phylum of kingdom Animalia.
Which is further subdivided into subphylums, divisions and classes.
The Slides shows the classification of the phylum along with the basis on which it is classified.
(includes examples along with pictures for easy understanding and memorizing)
A presentation for BSC biology semester 1 students. This rich presentation is about major phylum in animal kingdom, each phylum is explained in detail with their general characterstics. Can be used for presenting in college or school, teaching, learning, etc.
Cnidaria is a phylum containing over 9,000 species found only in aquatic and mostly marine environments. All cnidarians have radial symmetrical. There are two major body forms among the Cnidaria - the polyp and the medusa. Sea anemones and corals have the polyp form, while jellyfish are typical medusae.
Biological Classification
This ppt shows the details of biological classification. it gives a brief idea about the five kingdom classification with a detailed description of kingdoms monera, protista and fungi. a detailed description of viruses, viroids, prions and lichens have also been given....
For more details visit my youtube channel: (VIHIRA ACADEMY)
https://www.youtube.com/channel/UCxo06Nj-QWo_7SNvMyDnJCQ?view_as=subscriber
In this presentation, Phylum Cnidaria, Coelenterata is described. After watching this you will learn the characteristics of Phylum Cnidaria, Coelenterata, The Body Wall and Nematocysts, Alternation of Generations, Maintenance of Functions, Reproduction, Class Hydrozoa, Class Staurozoa, Class Scyphozoa, Class Cubozoa, Class Anthozoa, locomotion, Digestion, Nutrition,Exchanges with the Environment, Nervous and Sensory Functions, Reproduction and Development, cnidocytes, alternation of generations, polyps, medusa, dactylozooids gastrozooid, gonozoid, obelia, aurelia Jelly fish, coral reef, Hydra, Gonionemus, siphonophora, example and taxonomy of Phylum Cnidaria. It is part of BS Zoology Course Animal diversity.
1) Strategies and structuresIn Protozoans the method of movement .pdfaptelecom16999
1) Strategies and structures:
In Protozoans the method of movement is determined by the type of organism and the
surrounding environment. Protozoans mainly move by cell extension, flagella or pseudopodia
and cilia, the movement as per the presence of structure can be classified as ciliary, flagellar and
amoeboid movement.
Ciliates : Ciliates form the largest group of protozoa. These organisms vary in size and often live
in watery environments, including oceans, marshes, bays and streams. Ciliates move using tiny
cilia, which are hair-like strands that act as sensors and tiny limbs.
Flagella are longer and less numerous that cilia, they use their long tail like flagella to move.
Amoebas : In these two cytoskeleton get polymerized . This creates a vacancy and cytoplasmice
material flow to cover the vacancy created. When amoeba moves cytoplasm moves to the arm
like extension called pseudopodium. This pseudopodium extends and enlarge and hence this
push the animal body towards that respective direction.
2) A) Flagellates can live as single cells, in colonies, or as parasites.
Commonly live in niche\'s of water.
They conduct photosynthesis and have a cell wall.
They contain flagella for propulsion or to create a current to bring in food.
They can inhabit the reproductive tract, alimentary canal, tissue sites and also the blood stream,
lymph vessels and cerebrospinal canal.
B) Pseudopods : Also called as false feet , are projections that can appear and disappear from the
organism\'s body. These are used for movement and to engulf prey and digest them using
enzymes.
C) Apicomplexa : Unicellular and spore forming, most of them possess a unique form of
organelle that comprises a type of plastid called an apicoplast, and an apical complex structure.
They have apicoplast(non photosynthetic plastid) , mitochondria and nuclear genomes.
Lack of cilia, sexual reproduction, use micropores for feeding, and the production of oocysts
containing sporozoites as the infective form.
They have unique gliding capability which enables them to cross through tissues and enter and
leave their host cells. This gliding ability is made possible by the use of adhesions and small
static myosin motors.
3) Key characteristics of fungi :
Fungi are unicellular or multicellular.
Most of the fungi grow as tubular filaments called hyphae
They are haploid.
Fungus are heterotrophs (they can obtain nutrients by absorption) . They absorb food and secrete
enzymes to digest complex molecules
Propogate by spores
Asexual or sexual reproduction
They can be multinucleated
Fungi are achlorophyllous (lack of cholorphyll pigment)
Both Fungi and protists belong to same kingdom but fungi is different from protist, protists are
able to live in an anaerobic environment without oxygen but fungi need aerobic respiration to
survive.
Protists are unicellular but fungi are multicellular. Protists are autotrophic (make their own
energy) and heterotrophic (rely on outside source to get energy), but fungi a.
The determination of the sex in an animal is the complex system for deciding the sex of organism. it is depends on the chromosomes present in the animals. some animals determine the sex of an animal by external environmental factors.
The powerpoint presentation on blood pressure covers all the aspects of blood pressure, measurement of blood pressure and factors affecting blood pressure. it also explained the Hypertension and Hypotension in detail.
The dynamics of movement of xenobiotics in the living system from its penetration into the blood to its final elimination from the body is termed translocation. Translocation of the toxicants is completed by absorption, distribution, biotransformation and excretion.
Classical and molecular taxonomic parameters, species concept, systematic gradation of animals, nomenclature, modern scheme of animal classification into sub-Kingdom, division, section, phyla and minor phyla
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
2. • The occurrence of more than one type of structurally and
functionally different individuals within a population is called
polymorphism.
• The class Hydrozoa of phylum Coelenterata includes a large
number of colonial species that contain more than one form of
individuals which are called zooids Coelenterates have two basic
zooids, polyp and medusa.
• All other types of zooids are modifications of these two types of
zooids.
3. • Polyp has a tubular body with a mouth surrounded by tentacles
at one end. Other end is blind and usually attached by a pedal
disc to the substratum. Polyps are concerned with feeding,
protection and asexual reproduction.
• Medusa has a bowl or umbrella shaped body with marginal
tentacles and mouth is centrally located in a projection called
manubrium on the ventral concave surface. Medusae are
generally motile and concerned with sexual reproduction.
4. Modifications of Polyp
• Gastrozooids or feeding
zooids are typical polyps
with a mouth and
surrounding tentacles.
• Dactylozooids which are
used for defence are polyps
without mouth and usually
with a long basal tentacle.
• Gonozooids are
reproductive zooids derived
from polyp, which produce
sexual medusae or
gonophores.
5. Modifications of Medusa
Nectophore or nectocalyx or
swimming bell is a medusa
modified for sexual
reproduction.
Pneumatophore or float is a
bladder-like modified medusa
filled with mixture of gases
and helping the colony to float
on the surface.
Phyllozooids are leaf like Bract,
studded with nematocysts and
serving to protect the colony.
Gonophores bears gonads,
dioecious and produce germ
cells for reproduction.
6. TYPES OF POLYMORPHISM
A few coelenterates, such as Hydra and sea anemone are
monomorphic in which only polyp stage is found but other
coelenterates exhibit polymorphism.
Dimorphism: Many hydrozoan colonies like Tubularia and
Campanularia have only two types of zooids, the feeding zooids
or gastrozooids and medusae or nectophores that bud off from
the stem or gastrozooids.
Trimorphism: Some species like Obelia and Plumularia are
trimorphic because besides gastrozooids and medusa, they also
have medusa-producing gonozooids or blastostyle.
7. Polymorphism: In order Siphonophora, such as Diphyes,
Halistemmia, Stephalia and Physalia, zooids are so much modified
that they appear like organs of a single body rather than
individuals of a colony.
In Physalia, zooids are in units, which bear gastrozooids, small and
large dactylozooids with long and short tentacles and branched
gonozooid with gonophores.
In Velella and Porpita, there is a single large central gastrozooid with
a mouth, around which are arranged concentric rows of
gonozooids and dactylozooids. The whole colony looks like a
single individual.
8. ORIGIN OF POLYMORPHISM
There are two theories to explain the origin of polymorphism in
coelenterates.
Polyorgan theory: This theory was proposed by Huxley (1859),
Eschscholtz (1829), E. Metschnikoff (1874) and Muller (1871),
according to which individuals of a colony are actually organs of a
medusoid individual, which have multiplied and migrated from
their primitive positions to the current evolved positions.
Polyperson theory: This theory was first proposed by Leuckart
(1851), Vogt (1848), Gegenbaur (1854), Kolliker (1853), Claus
(1863) and later strongly supported by E. Haeckel (1888), Balfour
(1885) and Sedgewick (1888). According to this theory colony is
not a single individual but various parts of the colony are
modified individuals which have changed their structure due to
division of labour. They have all modified from the primitive zooid
which was a polyp.
9. SIGNIFICANCE OF POLYMORPHISM
• The phenomenon of polymorphism is essentially one of division
of labour in which specific functions are assigned to different
individuals.
• Thus, polyps are modified for feeding, protection and asexual
reproduction, while medusae are concerned with sexual
reproduction.
• This distribution of functions among diversified individuals and
their subsequent modifications in coelenterates may have
resulted from their initial simple organization and lack of organ
specialization.
• Polymorphism gave the colonies competitive edge in protection
and food gathering and eventual survival.