Podcast
Questions and Answers
Which characteristic distinguishes coelomates from pseudocoelomates?
Which characteristic distinguishes coelomates from pseudocoelomates?
- Coelomates have a body cavity not lined by mesoderm, while pseudocoelomates have a body cavity lined by mesoderm.
- Coelomates lack a body cavity, while pseudocoelomates have a body cavity lined by endoderm.
- Coelomates possess a body cavity lined by mesoderm, while pseudocoelomates have a body cavity not fully lined by mesoderm. (correct)
- Coelomates feature a body cavity between the ectoderm and endoderm; pseudocoelomates do not.
What is the key feature of metameric segmentation?
What is the key feature of metameric segmentation?
- External and internal division of the body into serially repeated segments. (correct)
- The absence of internal divisions corresponding to external segments.
- A single, undivided body cavity that enhances hydrostatic movement.
- A body plan where organs are arranged randomly without repetition.
Which of the following describes the origin and role of the notochord?
Which of the following describes the origin and role of the notochord?
- Endodermally derived, functioning in digestive processes in chordates.
- Mesodermally derived, serving as an early embryonic support structure in chordates. (correct)
- Ectodermally derived, providing structural support in non-chordates.
- Mesodermally derived, forming the primary excretory system in vertebrates.
How would you classify an animal that lacks a body cavity?
How would you classify an animal that lacks a body cavity?
What is the primary distinction between animals classified as chordates and non-chordates?
What is the primary distinction between animals classified as chordates and non-chordates?
Which of the following is a consequence of metamerism in annelids?
Which of the following is a consequence of metamerism in annelids?
An animal is described as triploblastic. What does this imply about its embryonic development?
An animal is described as triploblastic. What does this imply about its embryonic development?
How does the presence or absence of a coelom impact an animal's body plan?
How does the presence or absence of a coelom impact an animal's body plan?
Which of the following animals is classified as an acoelomate?
Which of the following animals is classified as an acoelomate?
Among the following animal groups, which one exhibits metamerism?
Among the following animal groups, which one exhibits metamerism?
Flashcards
Coelom
Coelom
Presence of a cavity between the body wall and gut wall is very important in classification. The body cavity which is lined by mesoderm is called coelom.
Metamerism
Metamerism
In some animals, the body is externally and internally divided into segments with a serial repetition of at least some organs. For example, in earthworm, the body shows this pattern called metameric segmentation and phenomenon is known as metamerism.
Notochord
Notochord
A mesodermally derived rod-like structure formed on the dorsal side during embryonic development in some animals.
Pseudocoelom
Pseudocoelom
Signup and view all the flashcards
Coelomates
Coelomates
Signup and view all the flashcards
Pseudocoelomates
Pseudocoelomates
Signup and view all the flashcards
Acoelomates
Acoelomates
Signup and view all the flashcards
Study Notes
- Animals with a third germinal layer, mesoderm, in between the ectoderm and endoderm are triploblastic (platyhelminthes to chordates).
Coelom
- Coelom is the presence or absence of a cavity existing between the body wall and the gut wall.
- Body cavity is very important in classification, is lined by mesoderm, and is called coelom.
- Animals possessing a coelom are coelomates, such as annelids, molluscs, arthropods, echinoderms, hemichordates, and chordates (Figure 4.3a).
- In some animals, the mesoderm is present as scattered pouches in between the ectoderm and endoderm.
- A body cavity that is not lined by mesoderm is called pseudocoelom.
- Animals possessing a pseudocoelom are pseudocoelomates, such as aschelminthes (Figure 4.3b).
- Animals without a body cavity are acoelomates, such as platyhelminthes (Figure 4.3c).
Segmentation
- In some animals, the body is both externally and internally segmented a serial repetition of some organs.
- In earthworms, the body shows a pattern known as metameric segmentation (or metamerism).
Notochord
- Notochord is a mesodermally derived rod-like structure formed on the dorsal side during embryonic development in some animals.
- Animals with a notochord are chordates, and those animals which do not form this structure are called non-chordates, such as porifera to echinoderms.
Classification of Animals
- Classification of Animalia based on common fundamental features is given in Figure 4.4.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
