1. Annelids and arthropods are two major invertebrate phyla. Annelids include segmented worms like earthworms and leeches, while arthropods include insects, spiders, and crustaceans.
2. Both phyla exhibit bilateral symmetry and segmentation of the body. In annelids, segments contain redundant organs, while in arthropods segments are specialized and contain jointed appendages.
3. Arthropods have an exoskeleton made of chitin, segmented bodies, and jointed appendages adapted for different functions. They dominate terrestrial habitats due to key adaptations like the exoskeleton and tracheal breathing system.
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
Insects, spiders, crabs, shrimp, millipedes, and centipedes are all arthropods. Arthropods have jointed feet, a segmented body, and an exoskeleton, a cuticle on the outside of their body. Arthropods have by far the greatest number of species of any animal group, at around 900,000 species
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
Insects, spiders, crabs, shrimp, millipedes, and centipedes are all arthropods. Arthropods have jointed feet, a segmented body, and an exoskeleton, a cuticle on the outside of their body. Arthropods have by far the greatest number of species of any animal group, at around 900,000 species
Unicellular aquatic Eukaryota organism that do photosynthesize. Plant-like protist. This presentation provides a generalize idea of protist focusing specifically on some characteristics of protist as well as their division.
There are main 5 classes of living echinoderms:
crinoids (sea lilies and feather stars); asteroids (STARFISH); ophiuroids (brittle stars); echinoids (SEA URCHINS, etc); and holothuroids (sea cucumbers).
Echinoderms have been well preserved as FOSSILS; all existing classes and several others now extinct were present in the Ordovician (505-438 million years ago). They may have originated in the Precambrian (over 570 million years ago).
Common name : sea lilies, Sea Stars(STARFISH), sea urchins, sea cucumbers, and brittle stars.
Habitat
Echinoderms occupy all habitats including coral reefs, mangroves, seagrass and soft-bottom areas.
Except for a few species which inhabit brackish waters, all echinoderms are benthic organisms found in marine environments. Echinoderms inhabit depths ranging from shallow waters at tide lines to the deep sea.(Barnes, 1987; Brusca and Brusca, 2003; University of Alabama Center for Communication and Educational Technology, 2000; Waggoner, 1999)
Habitat Regions
• temperate
• tropical
• polar
• saltwater or marine
Aquatic Biomes
• brackish water
Other Habitat Features
• intertidal or littoral
GeoGraphy and eco-system
Geographic Range
Mainly a marine group, echinoderms are found in all the oceans. (Brusca and Brusca, 2003)
BIOGEOGRAPHIC REGIONS
• arctic ocean
• indian ocean
• atlantic ocean
• pacific ocean
• mediterranean sea
Eco-system
Sea urchins are among the main herbivores on reefs and there is usually a fine balance between the urchins and the kelp and other algae on which they graze. A diminution of the numbers of predators (otters, lobsters and fish) can result in an increase in urchin numbers causing overgrazing of kelp forests with the result that an alga-denuded "urchin barren" forms.
Work cited:
Lawrence, J. M. (1975). "On the relationships between marine plants and sea urchins". Oceanographic Marine Biological Annual Review 13: 213–286.
Ecosystem Roles
Echinoderms are usually intricate parts of their ecosystems. Many asteroids are keystone species. Sea urchins, if not controlled by predators, may overgraze their habitat. Asteroids have several commensals, including polychaetes that feed on leftovers from the sea star's prey items. (Barnes, 1987; Brusca and Brusca, 2003)
Ecosystem Impact: keystone species
Unicellular aquatic Eukaryota organism that do photosynthesize. Plant-like protist. This presentation provides a generalize idea of protist focusing specifically on some characteristics of protist as well as their division.
There are main 5 classes of living echinoderms:
crinoids (sea lilies and feather stars); asteroids (STARFISH); ophiuroids (brittle stars); echinoids (SEA URCHINS, etc); and holothuroids (sea cucumbers).
Echinoderms have been well preserved as FOSSILS; all existing classes and several others now extinct were present in the Ordovician (505-438 million years ago). They may have originated in the Precambrian (over 570 million years ago).
Common name : sea lilies, Sea Stars(STARFISH), sea urchins, sea cucumbers, and brittle stars.
Habitat
Echinoderms occupy all habitats including coral reefs, mangroves, seagrass and soft-bottom areas.
Except for a few species which inhabit brackish waters, all echinoderms are benthic organisms found in marine environments. Echinoderms inhabit depths ranging from shallow waters at tide lines to the deep sea.(Barnes, 1987; Brusca and Brusca, 2003; University of Alabama Center for Communication and Educational Technology, 2000; Waggoner, 1999)
Habitat Regions
• temperate
• tropical
• polar
• saltwater or marine
Aquatic Biomes
• brackish water
Other Habitat Features
• intertidal or littoral
GeoGraphy and eco-system
Geographic Range
Mainly a marine group, echinoderms are found in all the oceans. (Brusca and Brusca, 2003)
BIOGEOGRAPHIC REGIONS
• arctic ocean
• indian ocean
• atlantic ocean
• pacific ocean
• mediterranean sea
Eco-system
Sea urchins are among the main herbivores on reefs and there is usually a fine balance between the urchins and the kelp and other algae on which they graze. A diminution of the numbers of predators (otters, lobsters and fish) can result in an increase in urchin numbers causing overgrazing of kelp forests with the result that an alga-denuded "urchin barren" forms.
Work cited:
Lawrence, J. M. (1975). "On the relationships between marine plants and sea urchins". Oceanographic Marine Biological Annual Review 13: 213–286.
Ecosystem Roles
Echinoderms are usually intricate parts of their ecosystems. Many asteroids are keystone species. Sea urchins, if not controlled by predators, may overgraze their habitat. Asteroids have several commensals, including polychaetes that feed on leftovers from the sea star's prey items. (Barnes, 1987; Brusca and Brusca, 2003)
Ecosystem Impact: keystone species
Scolopendra is the common centipede.
Nocturnal, predatory carnivore, found in tropical and sub-tropical countries.
Commonly lives in soil and beneath stones bark and logs in moist and damp areas and human dwellings.
Scolopendra gigantica is the largest of all living centipedes (grows up to a length of 30cm).
A presentation about Arthropods, its general morphology, life cycle, and habitat. This presentation also covers the first three subphyla which are Trilobitomorpha, Chelicerata, and Crustacea. The role of arthropods in disease transmission is also covered in the slides.
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.
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.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
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.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
3. Annelida - Systems
• Integument - epidermis is one cell layer with mucous
gland that secrete a moist cuticle.
• Skeletal - hydrostatic (using coelom).
• Muscle - longitudinal and circular muscles.
• Each segments muscles are independent of the other
segments.
• Digestive - complete, complex, with typhlosole for
absorption and chloragogen cells acting as digestive
gland and excretory cells.
4. Annelida - Systems
• Excretory - a pair of nephridia per segment.
• Respiratory - through skin, some through parapodia;
tubeworms have gills.
• Circulatory - closed system (5 hearts), use hemoglobin as
oxygen carrier.
• Nervous - dorsal brain; ventral, double, solid nerve cord,
with ganglia in each segment.
• Endocrine - hormones secreted by nervous system.
• Reproductive -
• Dioecious in Polychaeta; no special organs, posterior
end becomes gonads.
• Monoecious in Oligochaeta and Hirudinea; Clitellium.
6. Class Polychaeta
• Class: Class Polychaeta (mostly Marine)
• Have many setae/bristles.
• Highly specialised head regions.
i Antennae.
ii Sensory palps.
iii Feeding appendages.
• Paired extensions of body (parapodia).
• Often tube-dwelling.
• Burrow into substrate and secrete mucus
materials.
10. Class Oligochaeta
• Lack parapodia and have few setae.
• Lack the distinctive head region of polychaetes and
have no eyes.
• Scavengers that consume soil that contains organic
matter.
• The ingested soil moves into a storage chamber
called the crop, then to an area called the gizzard,
where grinding action breaks down the soil
particles.
• Undigested material passes out the anus in a form
called castings, which are prized as soil fertilizer.
12. Class Hirudinea
• Most live in fresh bodies of water, but some live among moist
vegetation.
• Dorso-ventrally flattened.
• Suckers found on both ends.
• Unlike other annelids, its segments are not separated internally.
• Leeches lack both setae and parapodia.
• Most are predators or scavengers (detritus feeders).
• Very few are parasites.
• They secrete anticoagulants, hirudin, to keep blood from
clotting and anesthetic that prevents the host from feeling their
presence.
14. Importance of Annelids
• Earthworms eat decomposing organic material
and dig tunnels in the soil aerating the soil.
• They act as decomposers and as fertilizers too.
• Leeches suck blood and are parasitic but
medicinally this has been used in blood-letting
and reconstructive surgery of severed digits and
plastic surgery.
• The water based annelids bio-monitor the
marine environment.
17. AP Biology
Arthropod groups
insects
6 legs, 3 body parts
crustaceans
gills, 2 pairs antennae
crab, lobster, barnacles,
shrimp
arachnids
8 legs, 2 body parts
spiders, ticks, scorpions
18. Phylum Arthropoda
• includes spiders, scorpions, horseshoe crabs,
centipedes, crustaceans, insects.
• The largest and most diverse animal phylum.
19. Phylum Arthropoda
• Almost 2/3 of all species that have been
described are arthropods.
• There may be as many as 30,000,000 species
of insects alone.
• Abundant in all habitats, but dominate in
terrestrial habitats.
• Most arthropods are small, but a few may be
as large as 3.6 m.
20. Phylum Arthropoda
• Economical, environmental and health
importance:
• Pollination.
• Food source.
• Pests.
• Disease vectors.
21. Phylum Arthropoda
Taxonomy of Arthropods
• Arthropods divided into three
subphyla - based on appendages:
1. Chelicerata:
• first appendages are for feeding –
(chelicerae -fangs of spiders,
feeding appendages of horseshoe
crabs).
2. Mandibulata: Crustacea and
Uniramia (Tracheata):
• first appendages are antennae, first
feeding appendages are called
mandibles.
3. Trilobita:
• Extinct.
24. Mandibulates: Crustaceans and
Uniramians
• Mandibulates are divided into two major groups -
Crustaceans and Uniramians (Tracheata) - based on
appendages.
• Crustaceans have biramous (branched) appendages.
• Uniramians (insects, millipedes, centipedes) have
uniramous (unbranched) appendages.
25. Key Innovations of arthropods
• Jointed appendages - Arthropod (jointed feet).
• Jointed appendages are specialised for different functions:
legs, mouthparts, antennae.
• Joints in appendages make them highly functional for
walking, and grasping.
• Antennae are sensory - sounds and chemicals.
• Mouth parts specialised for different food sources.
• Exoskeleton, segmental body with specialisation of
body regions.
26. Arthropods – Breathing mechanisms
• Terrestrial Uniramians and some Chelicerates have trachea.
• Trachea are branched tubules that allow air to diffuse into the
body
• Smaller tracheoles bring air to individual cells.
• Air entry controlled through external spiracles and closing of
spiracles conserves water.
• Flow is mostly passive - muscular movements can increase
flow.
• Limits body size because all cells must be able receive oxygen.
27. Arthropod – Skeletal Support System
• Rigid exoskeleton, made of chitin and protein helps
to protect organism against predators.
• Reduces desiccation (water loss) - allows life in dry
environments.
• Skeleton functions as attachment for muscles.
• Exoskeleton limits arthropods maximum size
although chitin is tough, it is brittle and cannot
support great weight without increasing its thickness
greatly.
• Exoskeleton must be shed in order for increase in size.
28. Arthropod - Moulting
• Growth requires periodic moulting - liability.
• New exoskeleton grows beneath old one
separated by a fluid that dissolves
components of old skeleton.
• Old skeleton cracks open and is shed.
• New skeleton is soft and must be expanded to
full size.
• Hardens with exposure to air or water.
29. Arthropods - Segmentation
• Segmental body plan clear in all forms.
• Segments fused to form specialised body regions.
• Insect: head, thorax, abdomen.
• Crustacean: cephalothorax, abdomen.
30. Arthropods - Eyes
• Ocelli are simple eyes with single lenses.
• Sometimes occur together with compound eyes.
• Function in distinguishing light and dark.
• Compound eyes: composed of many ommatidia.
• Each ommatidium receives its own image.
• it is connected to a nerve cell - entire image is integrated
in the brain.
31. Arthropod – Digestive system
• Gut is tubular and extends from mouth to
anus - with specialization: - crop, stomach
(midgut), hindgut, intestine, rectum.
32. Arthropod Circulatory system
• Circulatory system is open.
• Heart extends through thorax and abdomen.
• Contraction sends blood forward and
relaxation draws blood from tissues.
• One-way valves in heart allows blood to flow
forward only.
• Blood from anterior end flows through tissues
to posterior end.
33. Arthropods – Respiratory system
• Crustaceans have feathery gills under
carapace.
• Chelicerates have book gills and book lungs -
series of plates with thin respiratory
epithelium.
34. An efficient system that conserves water
- a good adaptation for terrestrial life
Arthropods - Excretion
• Several forms of excretory systems.
• Terrestrial Uniramians have Malpighian tubules.
• Slender tubular projections off the digestive tract at the junction of
the midgut and hindgut.
• Water and solutes pass through walls of tubules, nitrogenous
wastes are precipitated as uric acid.
• Fluid with waste is emptied into hindgut and eliminated.
• Most water and valuable solutes reabsorbed by hindgut.
35. Arthropods – Nervous System
• Double chain of ganglia runs along ventral surface.
• Three fused pairs of dorsal ganglia form the brain.
• Ventral ganglia control local activity of body regions.
• Many activities continue with brain removed.
• Some activities begin spontaneously when head is
removed.
36. Subphylum Chelicerata
Three Classes of Chelicerates
• Class Arachnida - spiders, scorpions, ticks
• Class Merostomata - horseshoe crabs
• Class Pycnogonida - sea spiders
37. Class Arachnida
• Spiders, daddy longlegs, scorpions, mites & ticks.
• All have a pair of chelicerae, pair of pedipalps, four pairs of
legs.
• Chelicerae are first appendages, fangs with poison glands.
• Pedipalps are next, similar to legs - rarely used for locomotion
often used for catching and handling prey.
• may also chew with basal portion.
• may function as copulatory organs or sensory organs.
• Scorpion pincers are pedipalps.
38. Class Arachnida
• Most are carnivorous, some mites are herbivorous.
• Most ingest only liquified foods, digestion begins externally.
• Most are terrestrial, direct transfer of sperm for reproduction.
• Respire with trachea, book lungs or both.
39. Class Merostomata
Horseshoe Crabs e.g.: Limulus sp, common on North Atlantic
coasts.
• Ancient group - Limulus fossils date to 220 million years old.
• Live in deep water, migrate to shallow coastal waters to
mate.
• Feed at night on molluscs and annelids.
• Shell-like carapace over cephalothorax protects most body
parts.
• Possess four pairs of walking legs, chelicerae and pedipalps.
• Respire via five pairs of book gills.
40. Class Pycnogonida
Sea Spiders.
• Common in marine habitats, especially
in cool waters.
• Rarely observed because of small size.
• Not closely related to spiders.
• Adults are parasites or predators on
other animals.
• Have sucking proboscis with terminal
mouth.
• Body consists mostly of cephalothorax,
no well-defined head.
• Possess four to six pairs of legs.
• Males exhibit parental care of young,
carry eggs on legs.
41. Subphylum Mandibulata
Class Crustacea – Crustaceans.
• Includes shrimp, crabs, crawfish, lobsters,
pillbugs, copepods, brine shrimp and
barnacles.
• Have biramous (two branch) appendages.
• Have two pairs of antennae.
• 3 pairs of feeding appendages.
• Larger forms have feathery gills near base of
legs.
42. Class Crustacea
• Have legs on thorax and abdomen like millipedes and
centipedes.
• Unlike insects crustaceans have two pairs of
antennae.
• Many have compound eyes.
• Have tactile (touch sensitive) hairs over whole body.
• Excretion of nitrogen wastes occurs mostly across
surface of cuticle.
• Variety of sexual styles and care of young.
43. Crustacean Diversity
• Decapod ("ten-footed") Crustaceans -
• includes lobsters, shrimp, crabs, crawfish.
• Exoskeleton reinforced with calcium carbonate.
• Anterior segments fused into cephalothorax, covered by
carapace.
• Crushing pincers common, used to obtain food and in
defence.
• Swimmerets used in reproduction and locomotion.
• Snapping of telson and uropods causes forceful, rapid
movement to the rear.
44. Crustacean Diversity
• Terrestrial forms - pillbugs, sowbugs, isopods.
• Amphipods are both terrestrial and aquatic.
Planktonic crustaceans:
• Subclass: Copepods (Copepoda).
• Subclass: Water fleas (Cladocera).
• Subclass: Ostracods (Ostracoda).
• Fairy shrimp and brine shrimp (Anostracoda).
45. Subphylum Uniramia
Uniramia (or Tracheata) - has three classes:
• Class Chilopoda – centipedes.
• Class Diplopoda – millipedes.
• Class Insecta – insects.
• Well adapted to terrestrial life.
• Respire with trachea.
• Malpighian tubules for excretion.
• Waxy cuticle on exoskeleton.
46. Classes Chilopoda and Diplopoda
Centipedes and Millipedes - both have head
tagmata followed by numerous repeating
segments - each with paired appendages.
• Centipedes (hundred legs) - have one pair of
legs per segment.
• Millipedes (thousand legs) - have two pairs of
legs per segment.
47. Class Chilopoda and Diplopoda
• Centipedes - carnivorous, most eat insects.
• Appendages of first body segment are poisonous
fangs.
• Millipedes - most are herbivorous.
• Can roll bodies into a flat coil.
• May secrete defensive fluids and cyanide gas.
• Reproduction similar in both groups.
• Sexes separate, fertilization is internal, copulate to
transfer sperm, all species lay eggs.
• Juveniles are similar to adults in appearance.
48. Class Insecta
Class Insecta – Insects.
• Largest group of organisms on earth - with
great diversity.
• Especially numerous in the tropics.
49.
50.
51. Class Insecta
• Most are terrestrial but many are aquatic in
freshwater.
• Have three body segments: Head, thorax,
abdomen.
• Have three pairs of legs, all attached to thorax.
• Have one pair of antennae.
• May have one or two pairs of wings.
• Sexes separate with internal fertilisation.
• Wings arise as sack-like outgrowths.
• Wings are solid except for veins.
52. Class Insecta
• Digestive tract is tubular and slightly coiled
digestion occurs within stomach or midgut.
• Excretion by Malpighian tubules.
• Respiration via trachea that extend
throughout body.
• Spiracles can be closed by muscles to retard
water loss.
53. Class Insecta
• Possess wide variety of sensory systems - in addition
to eyes.
• Sensory hairs located all over bodies especially on
legs and antennae.
• Sounds detected by tympanum.
• Sensory hairs may also detect sound waves.
• Produce sounds which may be inaudible to humans.
• Chemicals (pheromones) are also used to
communicate.
54. Class Insecta - Development
• Most insects hatch from laid eggs - rarely develop
within mother.
• After hatching young insects undergo development
through a series of instars.
• Often the larva is very different from the adult and
undergoes metamorphosis to become adult.
• Development is either through simple
metamorphosis or incomplete metamorphosis.