Lecture 17 Protostome Animals Flashcards
1
Q
Mollusk anatomy
- What is the foot
- What are feet modified as in bivalves
- What about Cephalopods
A
- Large muscle located at the base of animals used for movement
- As digging appendages in bivalves
- Tentacles for crawling in cephlapods
2
Q
What do snails and chitons have in common
A
- Large, muscular foot which Works as a hydrostatic skeleton called muscular hydrostat. Waves of muscle contractions sweep backward or forward allows individuals to crawl
3
Q
Mollusk anatomy: Visceral mass
- What is visceral mass
- Is this the same from the muscular foot
- What does the viceral skeleton seperate internal organs from
- Do mollusks have coelum
A
- Region in all mollusks where organs and fluids are located and seperates foot from rest of body
- Not the same
- Seperates Internal Organs from the hydrostatic skeleton
- Mollusks coelum is highly reduced which just functions in reproduction and waste excretion. Organs occupy a hemocoel instead.
4
Q
The Radula is Unique to mollusks
- Radula.
- How does the radula move over a food source
- When did radula evolve
- When is the radula lost
- Where is it located in comparison the the visceral mass?
A
- Mouth has feeding structure called radula and functions like a rasp or file. Located at the anterior end of the visceral mass
- Moves radula back and forth over food source
- Evolved in molluscan evolution
- Lost in bivalves which acquire food by suspension feeding
5
Q
Mollusk anatomy: Mantle
- What is the mantle
- What does it secrete
- Explain the mollusk shells
A
- Mantle- outgrowth of body wall that covers visceral mass forming enclosure called mantle cavity
- Secretes a shell made of calcium carbonate
- Some mollusk species have sgells with 1,2, or 8 parts called valves and can hinge/close
6
Q
What are some adaptations of the mantle that allow diverse functions other than secreting shells
A
- terrestrial snails mantal forms an internal lung
- Bivalves mantle is lined with muscle and forms tubes called siphons
- Cephalopods mantle forms siphone that functiosn in jet propulsion
7
Q
- What is an arthopod
- How many years ago did it appear in fossil record
A
- Most important phylum within Ecdyszoa
- 520 million years ago and the most abundant animals observed in both aquatic and terrestrial
8
Q
Arthropod Diversity
A
- Myriapoda- millipides, centipedes
- Insecta- Insects
- Crustacea- Shrimp, lobsters, crabs etc
- Chelicerata- Spiders, scorpians
9
Q
Arthropods Body plan
3 Key Features
A
- Exoskeleton
- Segmented Body
- Joint appendages
10
Q
Segment specialization in arthropods
1.How are mollusk and arthropod bodies similar
2.What do studies of hox genes and other tool kit genes
3.What does variation in gene expression combined with ecological opportunity thru natural selection
A
- Both have compartemantilized and flexible in evolutionary terms
- Show that small changes in timing and location of gene expression can result in novel shapes and sizes
- Results in diversification of anthropod body segments/appendages
11
Q
Origin of the wing
- First animal
- How many times did wings evolve
- Did wings evolve from jointled limbs of anthropods?
- Have wings evolved over time?
A
- First animal to achieve powered flight to escape predators and sarch for new food resources are insects
- Wings evolved only once before adaptive radition of insects on land (no transitional wings!)
- They did not evolve from jointed limbs as wings occur as they are unjointed extensions of dorsal cuticle on 2nd and 3rd segments of insect thorax
- Yes! many wings differ
12
Q
Arthopod metamorphosis
What are the 2 types of metamorphosis
A
- Incomplete- Hemimetabolous
- Complete- Homometabulous
13
Q
- Incomplete Metamorphosis
- Complete Metamorphosis
Are mosquitos complete/incomplete forms of metamorphosis
A
- Incomplete- Form of direct development and juveniles form nymphs (small versions of adults)
- Complete- Form of indirect development. Pupas forms after they have grown sufficiently as the body is completely remodeled during pupation
Complete!
14
Q
Is metamorpohosis adaptive
- Which type is more common
- Why
- What is another hypothesis
A
- Complete is 10x more common than incomplete
- Because of feeding efficiency as they do not compete with each other for resources in complete metamorphosis
- Functional specialization leads to higher efficiency in feeding
15
Q
Lophotrochozoans: Flatworms
- What is a flatworms
- What is the hypothesis in which their body is an adaption
- Do they have coelum
A
- Names for broad flattened shape of their bodies
- Flat body provides large surface area for gas exchange and allows nutrients and gases to diffuse efficiently to cells with minimal expenditure. Also allows flatworms to live in aquatic or moist environment
- Lack coelum aka acoelumates
