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.

1. Classification of
Phylum
Arthropods
Report by:
Veronica Baje

2. Objectives
1. Identify Phylum Arthropoda and its sub-
classes.
2. Learn the general morphology of
arthropods.
3. Know the in-dept details about
Subphylum Trilobitomorpha, Chelicerata,
and Crustacea.
4. Understand the role of arthropods in
disease transmission.

3. Phylum
Arthropoda
• Arthropoda /ärˈTHräpədə/ came
from the Greek words arthron which
means joint and podos which means
leg.
• Arthropoda dominate the animal
kingdom with an estimated 85% of
known species and many which are
yet to be documented.
• Phylum Arthropoda includes
animals that have been successful in
colonizing terrestrial, aquatic, and
aerial habitats.

4. Characteristics of
Arthropods

5. • The body structure shows
bilateral symmetry.
• They are tripoblastic.
• They can be found in all types of
habitats.
• They have jointed limbs.
• The body is segmented into
three regions—head, thorax,
and abdomen.
• The exoskeleton is hardened
and is made of chitin.

6. • They have a well-developed central nervous
system.
• The head is well developed and bears the
sensory organs and brain.
• They have compound eyes and mosaic vision.
• The body cavity is filled with blood and is
called the haemocoel. The blood is white in
color.
• The digestive tract is complete with the mouth
and anus at opposite ends of the body.

7. • They have an open circulatory
system with dorsal heart and
arteries.
• Respiration is through the
general body surface or by
gills in aquatic forms and
through trachea or book lungs
in terrestrial forms.
• Sexes are separate and sexual
dimorphism is exhibited.

8. Life Cycle of
Arthropods

9. • Arthropods reproduce sexually. Male
and female adults produce gametes.
If fertilization occurs, eggs hatch into
offspring.
• After hatching, most arthropods go
through one or more larval stages
before reaching adulthood. The
larvae may look very different from
the adults.
• They change into the adult form in a
process called metamorphosis.
During metamorphosis, the
arthropod is called a pupa. It may or
may not spend this stage inside a
special container called a cocoon.

11. • In some arthropods, newly
hatched offspring look like
small adults. These
arthropods don’t go
through larval stages. They
just grow larger until they
reach adult size. This type
of life cycle is called
incomplete
metamorphosis.

12. Respiration

13. Aquatic Arthropods
• Possess gills for
respiration. Although
they vary in structure
and location, the gills
are always outgrowths
of the integument (skin)
and are therefore
covered by the
exoskeleton, which is
thin in this area and not
a barrier to the
exchange of gases.

14. Terrestrial Arthropods
• Posses tracheae and
book lungs as respiratory
organs. In some
arthropods the tracheal
tubes are bathed by
blood, but in insects the
minute terminal endings
(tracheoles) are
embedded in the tissues,
even within muscle cells.
The tracheal tubes (but
not the tracheoles) are
molted along with the
rest of the exoskeleton.

15. Digestive System and
Feeding

16. • Arthropods exhibit every type of
feeding mode. They include
carnivores, herbivores, detritus
feeders, filter feeders, and
parasites, and there are
specializations within these
major categories.
• Typically, paired appendages
around the mouth are used for
collecting and handling food and
are usually specialized in
accordance with the particular
diet of the animal.

17. • The front and back parts of the digestive tract (foregut and hindgut) are
lined with the same skeletal material that is found on the outside of the
body and that is molted with the rest of the skeleton.
• Only the relatively small middle section (midgut) lacks a chitinous lining.
• In general, however, the midgut region is the principal site of enzyme
production and absorption of digested food.

18. Circulatory System

19. • Arthropods possess an open
circulatory system consisting
of a dorsal heart and a
system of arteries that may
be very limited (as in insects)
or extensive (as in crabs).
• The arteries deliver blood
into tissue spaces
(hemocoels), from which it
eventually drains back to a
large pericardial sinus
surrounding the heart.
• A varying number of paired
openings (ostia) are located
along the length of the heart
and permit blood to flow in
when the valves are open.

20. Excretory System

21. • Crustaceans and arachnids
possess paired excretory organs
(maxillary, antennal, or coxal
glands) that open at the bases of
certain appendages.
• Myriapods, insects, and some
arachnids, such as spiders and
mites, possess another type of
excretory organ, Malpighian
tubules, which open into the
intestine. Thus in these animals
both excretory and digestive
wastes exit from the anus.

22. Nervous System and
Organs of Sensation

23. • The arthropod nervous system consists
of a dorsal brain and a ventral,
ganglionated longitudinal nerve cord
(primitively paired) from which lateral
nerves extend in each segment.
• The sense organs (sensilla) on the body
surface involve some specialization of
the exoskeleton barrier.
• The sensory nerve endings are lodged in
cuticular hairs (setae), peglike
projections, cones, pits, or slits, which
may occur in large numbers on antennae,
mouthparts, joints, and leg tips.
• Changes in the tension of the
surrounding cuticle stimulate the nerve
endings.

24. • Most arthropods possess eyes, but in most
species they function only to detect the intensity
of light and the direction of the light source. The
ability to detect objects is more restricted.
• Among arthropods the greatest visual acuity is
found in the predaceous mantis shrimp, some
crabs, and many insects, all of which possess
compound eyes.
• Compound eyes are extremely effective in
detecting motion.

25. Reproductive System

26. • With few exceptions, the sexes are separate in arthropods.
• Arthropods reproduce sexually. Male and female adults
produce gametes. If fertilization occurs, eggs hatch into
offspring.

27. Classification of
Arthropoda

28. Annotated
Classification

29. Subphylum
Trilobitomorpha

30. Subphylum Trilobitomorpha
• Trilobites first appeared some 570 million
years ago, and were abundant during the early
part of the Paleozoic Era.
• They are the extinct forms of arthropods.
• Body is divided into three lobes, hence the
name trilobitomorpha.

31. General
Characteristics of
Trilobitomorpha
• Body is divided into a
median and two lateral
lobes by a longitudinal
axial furrow.
• Body division: head,
abdomen, and pygidium.
• Head bears a pair of
antenna and eyes.
• Eyes are compound.

32. Subphylum
Chelicerata

33. Subphylum Chelicerata
• There area about 77,000 living species of
chelicerates.
• The word Chelicerata from Greek words, khēlē
claw, chela and κέρας, kéras which means
horn.
• Chelicerates are an ancient group of
arthropods that first evolved about 500 million
years ago.

34. General Characteristics of
Chelicerata
• Chelicerates have two body segments (tagmenta)
and six pairs of appendages.
• Four pairs of appendages are used for walking
and two (the chelicerae and the pedipalps) are
used as mouthparts.
• Chelicerates have no mandibles and no antennae.
• Many chelicerates are unable to eat solid food
due to their narrow gut. Instead, they muThe
prey liquifies and they can then ingest the food.st
expel digestive enzymes onto their prey.

35. General Characteristics of Chelicerata
• The exoskeleton of a chelicerate is
a hard external structure made of
chitin that protects the arthropod,
prevents desiccation, and
provides structural support.
• Because of the rigid exoskeleton,
the animal molts periodically to
allow for increase in size.
• New exoskeleton is secreted by
the epidermis after molting.

36. Three Classes of
Chelicerata
• Xiphosura – Horseshoe crabs
• Pycnogonida – Sea spiders
• Arachnida – spiders, scorpions,
whip scorpions, ticks, mites,
pseudoscorpions, and
harvestmen
• Eurypterida – Sea scorpions
(Extinct)

37. Subphylum Crustacea

38. Subphylum Crustacea
• The term crustacean derives from the
Latin word crusta, meaning crust or
hard shell.
• Most of the 44,000 species of
crustaceans live in saltwater or
freshwater.
• A small number of crustaceans live on
land.

39. General Characteristics of Crustacea
• Thoracic and abdominal
appendages are biramous.
• Respiration is through gills.
• Excretion is through green
glands or antennal glands.
• Sense organs are antennae,
statocysts, and eyes.
• Eyes are compound.
• Has paired gonopores.

40. General
Characteristics of
Crustacea
• Their head and thorax fused
to form cephalothorax.
• Cephalothorax is usually
covered by single large
carapace.
• Has two pairs of antennae.
• Has five pairs of cephalic
appendages: first pair,
antennules; second pair,
antennae; third pair,
mandibles; fourth pair, first
maxillae; and fifth pair,
second maxillae.

41. 10 Classes of Subphylum
Crustacea
• Class Cephalocarida – horseshow shrimps
• Class Branchiopoda – tadpole, fairy, and brine shrimps
• Class Ostracoda – ostracods, seed shrimp
• Class Copepoda – copepods, fish lice
• Class Mystacocarida – mustache shrimp
• Class Remipedia – cave-dwelling blind shrimps
• Class Tantulocarida – parasitic crustaceans
• Class Branchiura -
• Class Cirripedia - barnacles
• Class Malacostraca – lobsters, crayfish, crabs, shrimps,
amphipods, isopods (including pillbugs and sowbugs), ad
mantis shrimps

42. Arthropods and their Role
in Disease Transmission

43. Role of Arthropods in
Disease Transmission
• Arthropod-borne diseases are
transmitted by arthropods which
includes insects, spiders, and
crustaceans.
• Mosquitoes, fleas, ticks, lice, and flies
are the arthropods that usually act as
vectors for various pathogens
including bacteria, viruses,
helminths, and protozoa.

44. Common Arthropod-borne
diseases
• Malaria
• Yellow Fever
• Changas Disease
• Dengue Fever
• Lyme Disease

45. Types of Arthropod-borne
Disease Transmission
• Mechanical Transmission
• Arthropod deposits pathogens
onto a surface from which a host
either absorbs or ingests them.
• Biological Transmission
• The arthropod injects the
pathogens directly into the body
of the host.

46. References:
• https://courses.lumenlearning.com/wm-biology2/chapter/phylum-
arthropoda/
• https://www.toppr.com/guides/biology/animal-kingdom/phylum-
arthropoda/
• https://www.britannica.com/animal/arthropod/Digestive-system-and-
feeding
• https://www.ck12.org/section/Insects-and-Other-Arthropods-::of::-MS-
Other-Invertebrates-::of::-CK-12-Life-Science-For-Middle-School/
• https://www.easybiologyclass.com/trilobitomorpha-trilobites-general-
characters-phylum-arthropoda/
• https://www.thoughtco.com/chelicerates-arthropods-129497
• https://www.encyclopedia.com/media/educational-magazines/arthropod-
borne-disease