Classification tree Phyla

Question 1

Phylum Porifera

Answer 1

• Parazoa (no true tissue/organs)
  -ex: Sponges
• No nerve or muscles
• Suspension feeders (filter feeder):
  Choanocytes (collar cells)
  
  • inner layer of flagellated cells
  • move water and food into sponge
  • food phagocytosed
• skeleton composed of spicules

Question 2

Phylum Cnidaria

Answer 2

• Radiata (Radial symmetry)
• Ex: Jellyfish, Coral, Anemones, Hydra
• Diploblastic
• Body plan: Sac with a central digestive compartment
  -Gastrovascular cavity
  
  • Two way with one opening: function as both mouth and
    anus
• 2 types of body plan;
  Sessile polyps:
  Cylindrical form: adheres to substrate
  Medusa:
  bell shaped form, oral opening down: moves freely in water by passive drift
  Some exhibit only one, others both (Obelia)
• Carnivorous organisms:
  tentacles around mouth/anus to capture prey
  push them into their gastrovascular cavity
  cnidocytes are the stinging cells

Question 3

Phylum Platyhelminthes

Answer 3

• Bilateria (first) -> bilateral symmetry
• Acoelomateb (no body cavity)
  -Ex: Flatworm: Planaria , Fluke, Tapeworm
  -Triploblastic
• moderate cephalization and muscle tissue
• Gastrovascular cavity: 2-way one opening
  Exception: Tapeworm(parasitic)
• absorbs pre digested food from host’s intestine through its surface
• lack coelom

Question 4

Phylum Nematoda

Answer 4

• Pseudocoelomate
  Ex: unsegmented Roundworms
• composed

Question 5

Phylum Annelida

Answer 5

• Protostomes
  -Ex: Segmented worms(earthworm, sandworm, leech)
  1. Segmentation:
  regional specialization
  groups of segment modified for different functions
  2. Coelom
  Serves as a hydrostatic skeleton
  3. Complete digestive system:
  mouth/pharynx, esophagus, crop (store food), gizzard (grind food), intestine
  4. Closed circulatory system:
• hemoglobin is present in blood cells
• five main pumping vessels
  5. Excretion:
• Metanephridia:
  excretory tubes found in each segment
  remove waste from blood and coelomic fluid
• waste exit through pores
  6. Lack circulatory system:
• Absorb O2 through its surface
• Sandworm uses parapodia (little projection) for resp and movement

Question 6

Phylum Arthropoda

Answer 6

• Protostomes

- Ex: Insects, Spiders, Crayfish

Question 7

Phylum Mollusca

Answer 7

• Protostomes

- Ex: Snails, Clams, Squid

Question 8

Phylum Echinodermata

Answer 8

• Deuterostomes

- Ex: Starfish, sea urchins

Question 9

Phylum Chordata

Answer 9

• Deuterostomes

Ex; Vertebrates

Question 10

Planaria(flatworm)

Answer 10

• Platyhelminthes
• lack specialized organs for gas exchange:
  gas exchange by diffusion
  all cells are close to water (flat)
• fine digestive system distribute food throughout animal
  Osmotic balance:
  ciliated cells called flame cells
  excretory system called protonephridia
• nitrogenous waste diffuses directly from cells to water
• eyespot which detect light

Question 11

Fluke

Answer 11

• platyhelminthes
• parasitic
• suckers for attachment to host

Question 12

tapeworm

Answer 12

• platyhelminthes
• parasitic
• uses digestive system of vertebrates
• absorbs its nutrients from host
• Scolex(head) contains suckers and hooks
• posterior to scolex: long ribbon of proglottids:
  filled with reproductive organs (hermaphroditic)