Animal Phyla

3. Phylum Porifera
•Sessile
•Feed by filtering food particles
from water that passes through
pores in their body
•Sponges
•Simplest animals
•Lack true tissues and
organs
•Asymmetrical

5. Phylum Cnidaria
•Jellyfish, Sea Anemone, Coral
•Tentacles with stinging cells
•Sessile or slow-moving
•Tentacles move food into the
mouth, then into a digestive sac
called the gastrovascular cavity
•Undigested food and wastes exit
back through the mouth
•Radial symmetry

7. Phylum Platyhelminthes
•Flatworms
•Mobile
•Most are free-living carnivores
-Muscular tube projects through the mouth and sucks in food
-Food is then transported to the gastrovascular cavity
-Undigested food and wastes exit through the mouth
•But some are parasitic
that absorb digested
food from inside a host
-Flukes
-Tapeworms

9. Phylum Nematoda
•Roundworms
•Complete digestive tract  has two openings. a
mouth and an anus, at opposite ends of a continuous
tube
•Decomposers, parasitic,
or free-living
•Human parasitic examples:
pinworm & hookworm

11. Phylum Annelida
-segmented worms (earthworms, leeches)
-longitudinal and circular muscle
fibers surrounding body wall
-closed circulatory system:
blood remains contained within vessels

13. Phylum Mollusca
-snails, slugs,
oysters, clams,
octopuses, and
squids

14. Phylum Mollusca Anatomy
Foot – muscular mass of tissue that functions in locomotion (video clip)
Mantle – outgrowth of body surface that drapes over the animal
– produces the shell in certain mollusks
– functions in respiration, waste disposal, and sensory reception

15. Mollusks have an open circulatory system
– a heart pumps blood into vessels
– the vessels open into chambers where the organs are bathed
in blood

17. Phylum Echinodermata
-sea urchins, sea stars, sea cucumbers
-spines and plates under the skin make up the
endoskeleton (but with no central spine)
-the water vascular system is
a network of water-filled
canals that aid movement
-tube feet function in
locomotion, feeding,
and respiration

19. Phylum Arthropoda
Most numerous and diverse animals
•75% of animals belong to this phylum
•global population is 1 billion billion (10
18
)
1. crustaceans (lobsters, crabs, shrimp)
2. arachnids (spiders, scorpions, mites, ticks)
3. insects
4. centipedes and millipedes

20. General Characteristics of Phylum Arthropoda
Segmented body (different segments):
•head – sensory antennae, eyes, mouthparts
•thorax – midsection that bears jointed appendages
•abdomen – houses digestive and reproductive organs

21. General Characteristics of Phylum Arthropoda
-open circulatory system with a copper-based blood called
hemolyph
-unlike humans, arthropod blood does not carry oxygen

22. General Characteristics of Phylum Arthropoda
How do arthropods get oxygen to their tissues?
Aquatic arthropods have gills
Terrestrial arthropods have trachea – a system of air tubes

23. Exoskeleton – external skeleton that
consists of proteins mixed with
chitin
– protection, avoid dehydration
Must molt periodically
General Characteristics of Phylum Arthropoda

24. Crustaceans
Head and thorax is fused  cephalothorax
Have antennae; mostly aquatic
Copepods play an enormous role in the food chain of marine and
freshwater communities

25. Arachnids
Head and thorax is fused  cephalothorax
No antennae; mostly terrestrial
Two pairs of mouthparts:
1. Fanglike mouthparts used to paralyze prey with poison
2. Mouthparts used to manipulate prey once it is paralyzed

26. Insects – the most successful arthropods
Entomology – study of insects
Reasons for success:
-ability to fly
-diverse feeding habits
-ability to metamorphasize

27. Many arthropods, including insects, have compound eyes
Compound eyes consist of many eyes (can be over 1,000!)
Excellent in detecting motion, however, poor image resolution

28. Metamorphosis
Metamorphosis – a process in which body form changes from the
sexually immature to the sexually mature stage
Incomplete metamorphosis:
-change is not dramatic
-molting causes insect to grow
Complete metamorphosis:
-larval stage function in eating and growing
-adult stage functions in moving and reproducing

29. Phylum Chordata

30. Notochord – flexible rod that extends down the length of the body
Invertebrate chordates – notochord becomes skeleton
Vertebrate chordates – notochord disintegrates
Chordates are named
after a structure that
is found in all
chordate embryos