lecture 3 Flashcards
what are the characteristic features of the different lineages of Mollusca and Annelida?
Annelida are segmented.
Mollusca are not segmented
what do Mollusca and Annelida have in common, and how do they differ?
In common:
coelom, closed circulatory system, excretory system, completely digestive system, a brain, sensory organs for detecting light, gills
Differ:
Mollusks- mantle & radula
Annelids-segmented
what anatomical structures and physiological systems allow squids and other cephalopods to be much more active than other types of mollusks?
3 main and then just read info under
4 and 5 is ones i would include
Squids and other cephalopods have a
- closed circulatory system,
- complex nervous system with giant nerve fibers. Giant nerve fibers connect the brain with muscles in the mantle, enabling quick responses to food/danger
- Many cephalopods use their excurrent siphon to move via jet propulsion, allowing them to move rapidly through the environment.
4-cephalopods have a much larger and more complex brains= highly intelligent
5-image forming eyes are similar to vertebrates
- foot and head fused
- tentacles catch prey
- radula forms beak to bite or press prey finely
what are the advantages of segmentation?
Aid in locomotion.
More efficient body movement through use of localized muscle contractions as part of the muscular system
4 lineages of mollusca and examples of each
- polyplacophora (chitons)
- Gastropoda (snails and slugs)
- Bivalvia (clams, scallops, oysters, muscles)
- Cephalopoda (octopuses, squids, nautiluses)
what is a radula
feeding structure of mollusca
name of excretory gland found in annelida and how many does it have per segment?
metanephridium
2
what are the 3 lineages of annelida
- polychaeta
- oligochaeta
- hirudinea (leeches)
what are the advantage to being triploblastic over diploblastic? 2
Has mesoderm
- faciliates development of true organs
- triploblastic includes the mesoderm which eventually develop into muscle and bone tissue
what are the advantage to having a true coelom over none or a pseudocoelom? 4
1- true coelom has a peritoneum acts as a shock acceptor, fluid protects
2- internal organs are bathed within fluid of the body cavity which acts as a shock absorber
3- organs can function independently of the movements of the body wall. This is not possible in acoelomate animals where internal organs are fixed within blocks of mesoderm
4-in a true coelom the organs are also surrounded by the mesenteries that extensions of the peritoneum. This means the organs are not just floating around randomly within the body cavity
how do you expect the arrangement of muscles in the body walls of annelids to affect locomotion
more controlled and efficient movements
Enables peristaltic movement- the circular and longitudinal muscles contract alternately, making the animal longer/shorter
which other structures do annelids have which further improve locomotion over platyhelminthes and nematodes
- Chaetae
2. segmented
Nematoda
- external covering
- circulatory system
- arrangement of mesoderm
- type of muscle
- chaetae?
- locomotion
Nematoda:
- smooth unsegmented cuticle
- open circulatory system
- pseudocoelomate (no peritoneum)
- longitudinal
- no chaetae
- whip-like contraction of longitudinal muscles
Annelida
- external covering
- circulatory system
- arrangement of mesoderm
- type of muscle
- chaetae?
- locomotion
- segmented
- closed circulatory system
- coelomate
- longitudinal and circular muscles
- chaetae
- peristaltic
which organ systems exhibits segmentation in most annelida (6)
respiratory surfaces; parts of the nervous, circulatory and excretory systems and the body wall and coelom
