ASSINGMENT
SUBJECT: ZOOLOGY
ROLL NO: 0082-BS-BIO-TECH-22
ASSIGNMENT TOPIC:
Homones with principal function each of Porifera, cnidarians, Platyhelminthes,
nemertean's, nematodes, mnolluscs, annelids. arthropods, and echinoderms,
invertebrates; an overview of the vertebrate endocrine.
SUBMITTED TO:
SIR AMIR ALI
SUBMITTED BY:
JAVERIA SHAHID
BS BIOTECNOLOGY ( 3RD SEMESTER )
1. Hormones in Porifera:
• Introduction to Porifera:
Porifera, commonly known as sponges, are simple multicellular organisms found
in aquatic environments. Unlike more complex animals, sponges lack tissues and
organs, making them the simplest animals.
• Hormones in Sponges:
Unlike higher animals, sponges do not have a well-defined endocrine system with
traditional hormones. Instead, they rely on chemical signals and interactions
between cells to coordinate various physiological processes.
• Chemical Signaling:
Sponges release chemical compounds, such as secondary metabolites, which
serve as signaling molecules. These chemical signals play a crucial role in
processes like larval settlement, metamorphosis, and defense mechanisms
against predators.
• Coordination and Communication:
While sponges lack classical hormonal systems, they exhibit coordination
and communication through a range of biochemical signals. These signals
influence the behavior and interactions of neighboring cells.
• Research Insights:
Studies on chemical ecology in sponges provide valuable insights into their
biological processes. Researchers investigate how chemical signaling contributes
to the overall functioning and adaptation of these simple yet ecologically
important organisms.
Percy, J. A. (1974).
2. Hormones in Cnidarians:
• Introduction to Cnidarians:
Cnidarians are a diverse group of animals that include jellyfish, corals, sea
anemones, and hydras. These simple organisms have a basic nervous system and
use a combination of neurotransmitters and peptide signals for communication.
While they do not have a complex endocrine system like higher animals, some
chemical signals play crucial roles in their physiology. Here's a simple explanation
of hormones and their principal functions in cnidarians:
•Neurotransmitters:
Cnidarians use neurotransmitters to transmit signals between nerve cells
(neurons) and muscles. Acetylcholine is a common neurotransmitter that plays a
role in muscle contraction.
• Peptide Signals:
Cnidarians produce and release peptide signals, short chains of amino acids, to
communicate important information within their bodies. These peptides may act
as local regulators influencing nearby cells.
• Nematocyst Discharge:
Cnidarians possess specialized cells called cnidocytes that contain stinging
structures called nematocysts. Hormonal signals trigger the discharge of
nematocysts, aiding in prey capture or defense.
• Metamorphosis:
Hormones play a role in the metamorphosis of certain cnidarian species. They
regulate the transformation from larval to adult forms, ensuring proper
development and survival.
• Feeding Response:
Chemical signals are involved in triggering feeding responses in cnidarians. These
signals may be released in response to the presence of prey, initiating the capture
and ingestion of food.
• Reproductive Signaling:
Cnidarians use chemical signals to coordinate reproductive processes. These
signals may influence the release of gametes (eggs and sperm) and the formation
of new colonies in colonial species.
• Environmental Sensing:
Hormonal responses in cnidarians can be triggered by environmental factors such
as changes in light, temperature, or nutrient availability. These responses help the
organism adapt to its surroundings.
• Stress Response:
Cnidarians may release chemical signals in response to stressors such as changes
in water quality or the presence of pollutants. These signals can induce protective
behaviors or physiological adjustments.
Understanding the hormonal and chemical signaling in cnidarians provides
insights into the basic mechanisms that govern their behaviors, responses to the
environment, and life cycle events. While the endocrine systems of cnidarians are
simpler compared to more complex animals, these signaling processes are
essential for their survival and adaptation.
3. Hormones in Platyhelminthes:
• Introduction to Platyhelminthes:
Platyhelminthes, commonly known as flatworms, are a phylum of simple
invertebrate animals. While they lack a complex endocrine system like higher
animals, they do exhibit some basic hormonal and chemical signaling
mechanisms. Here's a simple explanation of hormones and their principal
functions in platyhelminthes:
Overview of Hormones in Platyhelminthes:
Flatworms have a rudimentary nervous system and lack specialized endocrine
glands. However, they utilize simple chemical signals and neurotransmitters for
communication between cells.
Neuropeptides:
Platyhelminthes release neuropeptides, which are small protein-like molecules, to
transmit signals between nerve cells. Neuropeptides play a role in regulating basic
physiological processes, including movement and feeding.
Serotonin and Dopamine:
Flatworms use neurotransmitters like serotonin and dopamine to regulate muscle
contractions and movement. These chemicals help coordinate various activities,
such as locomotion and response to environmental stimuli.
Reproductive Hormones:
Platyhelminthes often exhibit complex reproductive strategies. Hormones, though
not well-characterized in these organisms, likely play a role in regulating
reproductive processes such as sexual maturation and the development of
reproductive organs.
Regeneration and Growth:
Flatworms are known for their remarkable regenerative abilities. Hormonal
signals are likely involved in the control of cell division and tissue regeneration
after injury.
• Chemical Signaling in Behavior:
Chemical cues and signaling molecules are important for behaviors such as finding
a mate, responding to environmental cues, and locating food sources. These
chemical signals help flatworms navigate their surroundings.
• Response to Environmental Stimuli:
Hormonal responses in platyhelminthes aid in adapting to changes in the
environment, including variations in light, temperature, and nutrient availability.
• Mating and Sexual Behavior:
Chemical signals, possibly including pheromones, play a role in the mating
behaviors of flatworms. These signals help individuals locate suitable mates and
coordinate reproductive activities.
It's important to note that the study of hormones in platyhelminthes is an
ongoing area of research, and our understanding of their endocrine systems is still
developing. While they lack the complexity of endocrine systems in higher
animals, the basic principles of chemical signaling and coordination are evident in
these simple organisms.
4. Hormones in nemerteans:
• Introduction to Nemerteans:
Nemerteans, commonly known as ribbon worms, are marine invertebrates that
belong to the phylum Nemertea. While they are not as extensively studied as
some other phyla, there is limited information available regarding their hormonal
systems. The understanding of nemertean hormones is still an evolving area of
research. As of my last knowledge update in January 2022, specific information on
nemertean hormones and their functions might be limited. However, I can
provide a general overview based on what was known up to that point:
Neuropeptides:
Principal Function: Neuropeptides in nemerteans are believed to play a crucial
role in the regulation of various physiological processes, including muscle
contraction, feeding behavior, and reproductive activities.
Serotonin:
Principal Function: Serotonin, a neurotransmitter and hormone, is involved in the
modulation of muscular activity in nemerteans. It likely plays a role in regulating
the contractions of the body wall muscles.
Neurotransmitters:
Principal Function: Neurotransmitters, such as acetylcholine, are involved in
mediating signals between nerve cells and muscle cells, contributing to the
coordination of movement and responses to environmental stimuli.
Peptide Hormones:
Principal Function: Peptide hormones may be involved in the regulation of
reproductive processes, including gamete production and release. These
hormones play a role in coordinating reproductive activities.
5. Hormones in Nematodes:
• Introduction:
Nematodes, also known as roundworms, are a diverse group of worms that play
essential roles in various ecosystems. Hormones in nematodes serve crucial
functions in regulating various physiological processes.
Here are some of the key hormones found in nematodes and their principal
functions:
• Ecdysteroids: Molting and Development
Function: Ecdysteroids are involved in regulating the molting process in
nematodes. Molting is the shedding of the old cuticle and the synthesis of a new
one, allowing for growth and development.
• Juvenile Hormones: Developmental Control
Function: Juvenile hormones play a role in regulating the transition from larval to
adult stages. They influence the development and maturation of nematodes.
• Insulin-like Peptides (ILPs): Growth and Reproduction
Function: ILPs in nematodes play a role in regulating growth, development, and
reproduction. They are involved in signaling pathways that respond to nutritional
conditions and influence reproductive decisions.
Morphology of nematodes
• Neuropeptides: Neural Signaling:
• Function: Neuropeptides function as signaling molecules in the nervous
system of nematodes. They play a role in neurotransmission and can affect
various physiological processes, including locomotion and feeding.
• Serotonin: Neurotransmission and Behavior
Function: Serotonin is a neurotransmitter that plays a role in modulating behavior
and neural activity in nematodes. It is involved in regulating processes such as
feeding, locomotion, and egg laying.
• Dopamine: Neurotransmission and Behavior
Function: Dopamine is another neurotransmitter in nematodes that influences
behavior and neural function. It can affect aspects of locomotion and response to
environmental stimuli.
Parasitic Nematode
•Oxytocin/Vasopressin-like Peptides: Reproduction and Social Behavior:
Function: Nematodes release oxytocin/vasopressin-like peptides that play a role
in reproductive behavior and social interactions. These peptides may influence
mate recognition and other aspects of reproductive behavior.
• Gonadotropins: Reproductive Regulation
Function: Gonadotropins in nematodes regulate the activity of the gonads and
influence reproductive processes. They play a crucial role in controlling the
production and maturation of gametes.
Understanding the hormonal regulation in nematodes is essential for unraveling
their complex life cycles, reproductive strategies, and responses to environmental
cues. The study of nematode hormones provides insights into the biology of these
organisms and may offer potential targets for the development of pest control
strategies in agriculture or interventions in parasitic nematode infections.
Belbolla huanghaiensis Huang & Zhang, 2005 (Nematoda)
6. Hormones in Molluscs:
• Introduction to molluscs:
Molluscs are a diverse group of invertebrate animals that includes snails, clams,
octopuses, and squid. While molluscs do not have a comprehensive endocrine
system like vertebrates, they do possess some hormones that play important
roles in regulating various physiological processes. Here are some hormones
found in molluscs along with their principal functions:
• Pedal Peptide (PP):
Principal Function: Involved in the control of locomotion and muscular activity,
particularly in the foot, which is a characteristic locomotory organ in many
molluscs. Peptide hormones play a crucial role in controlling feeding behavior and
the release of digestive enzymes in molluscs. They help in the assimilation of
nutrients from the environment.
Form and Function of Mollucus
• Egg-Laying Hormone (ELH):
Principal Function: Regulates reproductive processes, especially the release of
eggs. ELH is important in the context of reproductive behavior and fertility in
certain molluscs. ELH is a neuropeptide that induces the release of eggs from the
female reproductive system. It is crucial for the regulation of reproductive events
in molluscs, particularly in species where egg-laying is a complex and coordinated
process.
• Ovipostatin:
Principal Function: Inhibits egg-laying and is involved in the regulation of
reproductive processes. It plays a role in controlling the timing of egg-laying
events.
• Neuropeptide Y (NPY):
Principal Function: Plays a role in the regulation of feeding behavior and energy
metabolism. It is involved in the control of food intake and digestion. NPY-like
peptides play a role in the modulation of feeding behavior and digestive
processes in molluscs. They can influence the contraction of the gut and regulate
the release of digestive enzymes.
• Cerebral Peptide 1 (CP1):
Principal Function: Associated with the central nervous system, CP1 is involved in
the regulation of feeding behavior and other aspects of neural control. CP1 is a
neuropeptide found in the cerebral ganglia of molluscs. It plays a role in the
control of reproductive behaviors, including the release of eggs and sperm, as
well as other aspects of reproductive physiology.
• FMRFamide (Phe-Met-Arg-Phe-amide):
Principal Function: Acts as a neurotransmitter and neuromodulator, playing a role
in the modulation of neural circuits controlling various physiological processes,
including feeding and locomotion. FMRFamide is a neuropeptide that is widely
distributed in the nervous system of molluscs. It is involved in the regulation of
feeding behavior, modulation of sensory responses, and control of rhythmic
motor activities.
• Gonadotropin-Releasing Hormone (GnRH)-Like Molecule:
Principal Function: Regulates reproductive processes by influencing the release of
gonadotropins, which in turn affect the activity of gonads in molluscs. GnRH-like
peptides are crucial for the regulation of reproductive processes in molluscs. They
control the release of gonadotropins, influencing gamete production and
maturation.
It's important to note that the specific hormones and their functions can vary
among different species of molluscs. Additionally, our understanding of molluscan
endocrinology is still developing, and more research is needed to fully elucidate
the roles of various hormones in these fascinating creatures.
Sinentomon Yin, 1965 (Protura)
7. Hormones in Annelids :
• Introduction to Annelids:
Annelids are a diverse group of segmented worms that exhibit a wide range of
physiological and reproductive characteristics. While they do not have a
specialized endocrine system comparable to vertebrates, they do possess certain
hormones and chemical signaling mechanisms that regulate various physiological
processes. Here are some of the hormones found in annelids and their principle
functions:
• Ecdysteroids: Molting and Growth
Annelids produce ecdysteroids, which play a crucial role in the molting process
(ecdysis) and overall growth.
Ecdysteroids are responsible for initiating the shedding of the outer cuticular layer
during molting, allowing the worm to grow and develop.
• Juvenile Hormones: Reproductive Maturation
Some annelids, particularly those with complex life cycles, may produce juvenile
hormones that influence the timing of reproductive maturation.
These hormones play a role in regulating the transition from juvenile to adult
stages, affecting sexual development and reproduction.
• Neuropeptides: Nervous System Regulation
Annelids utilize neuropeptides as signaling molecules that regulate various
physiological processes, including muscle contractions, feeding behavior, and
reproductive activities.
Neuropeptides function as neurotransmitters and neuromodulators, transmitting
signals within the nervous system.
• Serotonin: Neural and Behavioral Functions
Serotonin is a neurotransmitter in annelids that modulates neural and behavioral
functions.
It plays a role in regulating muscle contractions, feeding behavior, and responses
to environmental stimuli.
• Prostaglandins: Inflammation and Reproduction
Annelids produce prostaglandins, which serve as signaling molecules involved in
inflammation and reproduction.
Prostaglandins may play a role in regulating smooth muscle contractions, immune
responses, and aspects of reproductive physiology.
It's important to note that the study of hormones in annelids is an evolving field,
and the understanding of specific hormones and their functions may vary among
different species. Additionally, some annelids may exhibit variations in hormonal
regulation based on their ecological niche and life history strategies.
(Holthuis & Menon, 2014)
8. Hormones in Arthropods:
• Introduction of Arthropods:
Arthropods are a diverse group of invertebrates that includes insects, arachnids,
crustaceans, and myriapods. Hormones play a crucial role in regulating various
physiological processes in arthropods. Here are some key hormones with their
principal functions in arthropods:
• Ecdysteroids: Molting Hormones
Principal Function: Regulate molting and metamorphosis.
Description: Ecdysteroids are responsible for initiating the process of molting,
during which arthropods shed their exoskeleton to grow. They also play a role in
the transformation from larval to pupal and pupal to adult stages.
• Juvenile Hormones (JH): Growth and Reproduction Regulators
Principal Function: Control growth, development, and reproductive processes.
Description: Juvenile hormones prevent the premature development of adult
characteristics in larvae. They also influence reproductive maturation and are
involved in the regulation of caste determination in social insects like ants and
bees.
• Insulin-Like Peptides (ILPs): Growth and Nutrient Sensing
Principal Function: Regulate growth and nutrient utilization.
Description: ILPs play a role in coordinating growth with nutrient availability. They
are involved in signaling pathways that influence the development and size of
arthropods.
• Neuropeptides: Neurotransmitters and Neuromodulators
Principal Function: Transmit nerve signals and modulate physiological processes.
Description: Neuropeptides act as neurotransmitters and neuromodulators in the
nervous system of arthropods. They play a crucial role in regulating various
physiological functions, including behavior, feeding, and reproduction.
• Methoprene: Insect Growth Regulator
Principal Function: Acts as a juvenile hormone analog.
Description: Methoprene is a synthetic compound that mimics the action of
juvenile hormones. It is often used as an insect growth regulator in pest control to
disrupt the normal development of insects.
• Allatostatins: Inhibitors of Juvenile Hormone Synthesis
Principal Function: Suppress the production of juvenile hormones.
Description: Allatostatins act to inhibit the synthesis of juvenile hormones,
thereby regulating the balance between juvenile and adult forms during
development.
Understanding the roles of these hormones provides insights into the complex
regulatory networks that govern the growth, development, and reproduction of
arthropods.
(Denholm, Devine & Williamson, 2002)
9. Hormones in Echinoderms:
Introduction to Echinoderms:
Echinoderms are marine animals belonging to the phylum Echinodermata, and
they include familiar organisms such as sea stars, sea urchins, and sea
cucumbers. While echinoderms do not have traditional endocrine systems like
vertebrates, they do exhibit hormonal control through various chemical
messengers that regulate physiological processes. Here are some of the key
hormones found in echinoderms and their principal functions:
• Steroids:
Principal Function: Steroids play a role in regulating growth, development,
and reproduction in echinoderms.
• Ecdysteroids:
Principal Function: Ecdysteroids are involved in molting, the process of
shedding the outer exoskeleton during growth and development.
• Peptides:
Principal Function: Peptide hormones regulate various physiological
processes, including muscle contractions, response to environmental
stimuli, and reproduction.
• Insulin-like Growth Factor (IGF):
Principal Function: IGF is involved in growth regulation, promoting cell
division and overall development.
• Neuropeptides:
Principal Function: Neuropeptides serve as neurotransmitters and
neuromodulators, playing a role in the nervous system and behavioral
responses.
• Prostaglandins:
• Principal Function: Prostaglandins are involved in inflammation and
immune responses, contributing to the overall maintenance of
homeostasis.
• Gonad-Stimulating Hormone (GSH):
Principal Function: GSH regulates the activity of gonads, influencing
reproductive processes such as gamete production and release.
• Serotonin:
Principal Function: Serotonin acts as a neurotransmitter and is involved in
various physiological processes, including muscle contraction, feeding
behavior, and mood regulation.
• Melatonin:
Principal Function: Melatonin may play a role in circadian rhythm
regulation and response to environmental light conditions.
It's important to note that echinoderms have decentralized nervous and
hormonal systems, and their hormonal control is not as well-studied as in
vertebrates. Additionally, the specific hormones and their functions may
vary among different echinoderm species.
(Liu et al., 2013)
OVERVIEW OF VERTEBRATE ENDOCRINE:
The vertebrate endocrine system is a regulatory network of glands and organs
that produce hormones, chemical messengers that control various physiological
processes. Key components include the hypothalamus, pituitary gland, thyroid
gland, adrenal glands, pancreas, ovaries (in females), and testes (in males).
Hormones travel through the bloodstream, binding to specific receptors on target
cells or organs to regulate functions like metabolism, growth, and reproduction.
The endocrine system works in tandem with the nervous system, using feedback
mechanisms to maintain internal balance. Disorders in this system can lead to
conditions such as diabetes and thyroid disorders. Overall, the endocrine system
plays a crucial role in coordinating and maintaining the body's essential functions.
Here's an overview of the key components and functions of the vertebrate
endocrine system:
•
•
•
•
•
•
1. Endocrine Glands:
Pineal Gland: Produces melatonin, a hormone that regulates sleep-wake
cycles.
Hypothalamus: Acts as a link between the nervous and endocrine systems,
producing releasing and inhibiting hormones that control the pituitary
gland.
Pituitary Gland (Master Gland): Produces and releases a variety of
hormones that regulate other endocrine glands, including growth
hormone, thyroid-stimulating hormone, and adrenocorticotropic hormone.
Thyroid Gland: Produces thyroid hormones that regulate metabolism and
influence growth and development.
Parathyroid Glands: Produce parathyroid hormone, which regulates
calcium and phosphorus levels in the blood.
Thymus: Produces hormones that play a role in the development of the
immune system, particularly T lymphocytes.
• Adrenal Glands: Produce hormones such as cortisol (regulates stress
response), aldosterone (regulates salt balance), and adrenaline (involved in
the fight-or-flight response).
• Pancreas: Produces insulin and glucagon, which regulate blood sugar
levels.
• Ovaries (in females): Produce estrogen and progesterone, which regulate
the menstrual cycle and contribute to female secondary sexual
characteristics.
• Testes (in males): Produce testosterone, which regulates sperm production
and contributes to male secondary sexual characteristics.
2. Hormones:
Hormones are chemical messengers produced by endocrine glands and released
into the bloodstream. They travel to target cells or organs, where they exert their
effects by binding to specific receptors.
3. Feedback Mechanisms:
The endocrine system operates through feedback mechanisms to maintain
balance in the body. Negative feedback loops help regulate hormone levels. For
example, when blood glucose levels rise, insulin is released to lower them, and
vice versa.
4. Integration with the Nervous System:
The endocrine system and nervous system often work together to coordinate
physiological responses. The hypothalamus and pituitary gland, in particular, play
crucial roles in integrating signals from the nervous system and regulating
hormone release.
5. Development and Reproduction:
Hormones play a crucial role in the development of an organism, influencing
growth, maturation, and the maintenance of homeostasis. Reproductive
hormones regulate the menstrual cycle, sperm production, and secondary sexual
characteristics.
6. Disorders:
Imbalances in hormone levels can lead to various disorders, such as diabetes,
thyroid disorders, and hormonal imbalances affecting growth and development.
Understanding the vertebrate endocrine system is essential for comprehending
how organisms regulate and maintain the diverse functions necessary for survival
and well-being.
Pipadentalium Yoo, 1988 (Scaphopoda)
REFRENCES
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internationales de la Nomenclature Zoologique adoptées par les Congrès
Internationaux de Zoologie. International Rules of Zoological Nomenclature.
Internationale Regeln der Zoologischen Nomenklatur. Paris (Rudeval)
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Bulletin of Zoological Nomenclature 31 (4): 206-208.
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• Book: "The Invertebrates: An Illustrated Glossary" by Ruppert, Fox, and
Barnes:
• Suggested journals include the "Journal of Endocrinology," "Endocrine
Reviews," and "Annual Review of Physiology
• " The Earthworm Book: How to Raise and Use Earthworms for Your Farm
and Garden" by Jerry Minnich
• The National Center for Biotechnology Information (NCBI) and PubMed
provide numerous research articles and reviews on endocrine physiology.
"Echinoderms: Durham" edited by M. Jangoux and J.M. Lawrence
• Animal Diversity Web (ADW):
• Website: https://animaldiversity.org/
• ADW is an online database that provides information on the biology of
animals, including descriptions, behavior, distribution, and classification.
• The World Register of Marine Species (WoRMS):
• Website: http://www.marinespecies.org/