1. Review - Can you name and give an example of each invertebrate phyla?
Ancestral protists

2. Porifera
Platyhelminthes
Mollusca
Arthropoda
Chordata
Cnidaria
Nematoda
Annelida
Echinodermata
Pseudocoelom
PROTOSTOMES Coelom from cell masses
DEUTEROSTOMES Coelom from digestive tube
Review - Can you complete the missing invertebrate evolutionary features?
Bilateral symmetry
No true tissues
Ancestral protists

3. Chordates
The proper name for vertebrates is chordates. All chordates share three features at some stage in their life:
Dorsal nerve cord – a main nerve for the body from which other nerves branch off
Notochord – a rod of cartilage along the back of the body, often found only in the embryo
Gill slits – in the pharnyx or throat. In terrestrial animals this is only seen in the embyro.

4. Chordates

5. In human embryos the part that develops into gills in fish become pharyngeal arches. The first arch becomes the jawbone, others parts of the ear and head.

6. Invertebrate Chordates !!
There are two unusual groups in the chordate family, tunicates (sea squirts) and lancelets.
They have no head and lack a brain but they do have all 3 features of chordates.
Head
NOTOCHORD
DORSAL,
HOLLOW NERVE CORD
Mouth
Pharynx
PHARYNGEAL SLITS
Digestive tract
Water exit
Anus
POST-
ANAL TAIL

7. Vertebrate Chordates The vertebrates are divided into two groups:
Agnathans or jawless fish which are the oldest chordates in the oceans. Examples include lampreys and hagfish.

8. Vertebrate Chordates
Gnathostomata or jawed animals. The jaw is an evolutionary trait that increased the range of food choices. Jawed fish are divided into:
the ancient cartilaginous fish like sharks and rays
The bony fish like salmon
Jaw bones evolved
by the modification
of skeletal supports
of the gill slits.

9. Evolution of
marine chordate animals. E
Fish phylogeny

10. Evolution of
land chordate animals.

11. Land Chordates On land the four phyla of vertebrates are:
Amphibians – cold blooded animals, adults have 4 limbs, start life in water, adults live on land
Reptiles – cold blooded animals, have developed an amnion or sac to protect the eggs laid on land
Birds – warm blooded animals that have developed a beak, and feathers for flying
Mammals – warm blooded animals, have hair and feed their young milk from mammary glands. Some mammals have moved from land back into water like seals, otters, dolphins and whales.
Homework – Read p 504 – 508
Complete the worksheet