Parazoa
Eumetazoa
Bilateria
Onychophora
Protostomia
Tardigrada
Nemerteans
Coelomates
Pseudocoelomates
Nematoda
Ctenophora
Porifera
Cnidaria
Acoelomates
Rotifera
Platyhelminthes
Radiata
The Animal Kingdom:
The Protostomes
(Part Deux)
Deuterostomia
Cephalization
• Evolution of a head
– concentration of sense organs and nerve cells
(simple brain) at anterior end
Segmentation
Segmentation
Pseudocoelom
Deuterostome
development
Chapter 30
• Increases effectiveness of bilateral animal
– to actively find food, shelter, mates
– to detect enemies
True coelom
Radial
symmetry
Protostome development
Three tissue layers (mesoderm)
Bilateral symmetry
Tissues (ectoderm and endoderm)
Choanoflagellate Multicellularity
ancestor
Fig. 29-7, p. 627
Parazoa
Eumetazoa
Bilateria
Coelomates
Onychophora
Pseudocoelomates
Deuterostomia
Arthropoda
Tardigrada
Protostomia
Rotifera
Nemerteans
Ctenophora
Porifera
Cnidaria
Acoelomates
Nematoda
Platyhelminthes
Radiata
Phylum: Arthropoda
- Most successful group of animals
- More than 1 million species described
Segmentation
Segmentation
Pseudocoelom
Deuterostome
development
- 2/3 of all classified species
True coelom
Radial
symmetry
Protostome development
Three tissue layers (mesoderm)
Bilateral symmetry
Tissues (ectoderm and endoderm)
Multicellularity
Choanoflagellate ancestor
Fig. 29-7, p. 627
1
Segmented bodies
Arthropod Characteristics
•
• Segmented animals with paired, jointed
appendages
Specialized respiratory systems
- aquatic critters have gills
- terrestrial critters have tracheae
- some have book lungs
• Armor-like exoskeleton of chitin
•
• Molting necessary for arthropod to grow
• Open circulation (hemolymph)
Nervous system
- paired ventral nerve cords w/ ganglia
- organs for hearing + touch
jointed appendages
bilateral symmetry
Antenna
exoskeleton
open circulatory system
Chelicerates: no antennae & no chewing
mandibles
Subphylum
Head
Phylum
Chelicerata (Chelicerates)
Head
Eye
Arthropoda
Gill
Crustacea
(Mandibulates)
Pedipalps
#2
Hexapoda
Lateral lobe
Myriapoda
Median lobe
Chelicerae
#1
(a) Dorsal view
Trilobites
500 mya – extinct for 250 my
(b) Ventral view.
Fig. 30-19ab, p. 658
2
Subphylum Myriapoda
Mandibulates
• 2 Classes
– Chilopoda (centipedes)
– Diplopoda (millipedes)
Antenna
(1 or 2)
Myriapods
Head
• Uniramous (unbranched) appendages
Mandibles (2 or 3)
• Single pair of antennae
Chelicerates
Subphylum: Chelicerata
Class: Arachnida (spiders, scorpions, mites)
65,000 spp.
- 4 pairs of legs , chelicerae, pedipalps
- Most are carnivorous
- gas exchange is by tracheae or book lungs
- poisonous
3
Subphylum Crustacea
•
•
•
•
•
•
Lobsters, crabs, shrimp, pill bugs, barnacles
2 sets of antennae
Body with cephalothorax and abdomen
Most have five pairs of walking legs
Green glands
Appendages are biramous
Crustaceans
Subphylum Hexapoda
• Includes class: Insecta
– articulated, tracheated hexapods
Head
Thorax
Abdomen
Forewing
Antenna
Simple eye
Compound eye
Sound receptor
Spiracles
Hindwing
(a) External structure. Note the three pairs of segmented legs.
4
Insects
•
•
•
•
•
Body with head, thorax, and abdomen
Uniramous appendages
Single pair of antennae
Tracheae for gas exchange
Malpighian tubules for excretion
Insect Adaptations
tracheae
•
•
•
•
•
Versatile exoskeleton
Segmentation
Specialized jointed appendages
Highly developed sense organs
Ability to fly
Insect Adaptations
• Insects have developed
– effective reproductive strategies
– effective mechanisms for defense, offense
– ability to communicate
spiracles
5
Insect Adaptations
• Metamorphosis: transition from one developmental
form to another
- reduces intraspecific competition
Egg
Incomplete metamorphosis
Complete metamorphosis (most insects)
egg
larva
Nymph
pupa
adult
Adult
Parazoa
Eumetazoa
Bilateria
Onychophora
Protostomia
Annilda
Deuterostomia
Arthropoda
Tardigrada
Nemerteans
Coelomates
Pseudocoelomates
Rotifera
1 1/2 teaspoon lemon juice
Ctenophora
2 cup low-fat cottage cheese
Porifera
Rootworm Beetle Dip
Cnidaria
Acoelomates
Nematoda
Platyhelminthes
Radiata
2 tablespoons skim milk
1/2 cup reduced calorie mayonnaise
Segmentation
Segmentation
Segmentation
1 tablespoon parsley, chopped
Pseudocoelom
1 tablespoon onion, chopped
1 1/2 tsp. dill weed
1 1/2 tsp. Beau Monde
1 cup dry-roasted rootworm beetles
Deuterostome
development
True coelom
Radial
symmetry
Protostome development
Three tissue layers (mesoderm)
Bilateral symmetry
Tissues (ectoderm and endoderm)
Multicellularity
Choanoflagellate ancestor
Fig. 29-7, p. 627
6
Phylum: Annelida (segmented worms)
• Metamerism (segmentation)
• Benefits?
- Segment damage not fatal
- Efficient locomotion
- Segmented parts can be specialized
• Closed circulatory system
- faster more efficient
• Metanephridia
Ganglia
Metanephridia
3 classes of Annelids
Class: Polychaeta
Class: Oligocheata
Marine worms
Parapodia
- Parapodia
- earthworms
- take in organic matter
- Distinct head
- Palolo
- Sexes separate
- Hermaphroditic but still crossbreed
7
Leeches
Class: Hirudinia
Leeches
- parasitic, scavengers, predators
- Used for medicinal purposes
8
Parazoa
Eumetazoa
Bilateria
Coelomates
Pseudocoelomates
Mollusca
Annilda
Deuterostomia
Arthropoda
Tardigrada
Onychophora
Protostomia
Rotifera
Nemerteans
Ctenophora
Porifera
Cnidaria
Acoelomates
Nematoda
Platyhelminthes
Radiata
Segmentation
Segmentation
Pseudocoelom
Deuterostome
development
True coelom
Radial
symmetry
Phylum: Mollusca (Chitons, snails, clams, slugs,
squids)
• 50,000 living species
- aquatic and terrestrial
• Important to us
- food
- jewelry
- hosts for parasitic worms
- Zebra mussels
Protostome development
Three tissue layers (mesoderm)
Bilateral symmetry
Tissues (ectoderm and endoderm)
Multicellularity
Visceral mass
Mantle
Radula
Separate sexes (most)
Choanoflagellate ancestor
Fig. 29-7, p. 627
Trochophore larva
Class: Polyplacophora (chitens)
Most mollusks
Metanephridia
Open circulatory system
- hemocoel
- hemolymph
Veliger larva
29.2
9
Class: Gastropoda (Snails and slugs)
Class: Bivalvia
10
Class: Cephalopoda
(Octopods, squids, nautilus)
Tentacles
(modified
foot)
Internal
shell
Digestive
tract
Class Cephalopoda
Fig. 30-6d, p. 647
11