Download Winter 2016 Bio 94 Activity- Week 6

Winter 2016 Bio 94 Activity- Week 6- KEY
Part I
Protostomes and deuterostomes are the two main groups of bilaterally-symmetric animals
with three germ cell layers. The two main differences between these groups are found in
the developmental stages: gastrulation and coelom formation.
1. Draw an example of any bilateral animal.
2. What are the three germ layers that form during development?
Endoderm, Mesoderm, Ectoderm
3. Draw gastrulation (formation of the gut and embryonic germ layers) in a protostome.
Be sure to clearly distinguish between layers and label what the pore becomes.
Pore becomes mouth first, only endoderm is formed
Pore becomes mouth first, only endoderm is formed
4. Now draw the formation of the coelom (body cavity lined with mesoderm).
5. Much like the green algae that eventually adapted to life on land, protostomes made
the transition from land to water multiple times as they diversified and faced the
following challenges:
Exchange gases, avoid drying out, hold up their bodies under their own weight
6. Think about protostomes such as annelids, mollusks, nematodes, and arthopods (e.g.
insects and crustaceans) and give two examples of animals and their adaptations to one of
the three challenges of living on land.
e.g. crab has an exoskeleton which helps support its weight and prevents dessication
e.g. insect with trachea to transport oxygen to its entire body
e.g. worms have high surface area to better exchange gases with the surrounding soil
Part 2
WORD BANK:
Lophotrochozoa
Lobster
Ecdysozoa
Coelom
Flatworm
Loss of Coelom
Earthworm
Protostome
Octopus
Pinworm
WORD BANK:
Lophotrochozoa
Lobster
Ecdysozoa
Coelom
Flatworm
Loss of Coelom
Earthworm
Protostome
Octopus
Pinworm
2. For each of the Species in question 1, state whether the animal is aquatic or terrestrial
Pinworm: aquatic and terrestrial
Earthworm: terrestrial
Lobster: aquatic (arthropods mainly terrestrial)
Flatworm: aquatic
Octopus: aquatic
3. Ecdysozoa are animals that shed a tough external coat (cuticle) called molting. Which
phylum in Ecdysozoa is characterized by animals that have a segmented body?
Arthropods
4. What is the difference between incomplete and complete metamorphosis?
Incomplete metamorphosis the young resemble the adults but are smaller, have different
body proportions, and lack wings. Insects with complete metamorphosis have larval
stages that specializes in eating and growing and are known as grub, caterpillar or
maggot. The larval stage looks completely different from the adult.