Which of the following statements about deuterostomes is false? Deuterostomes are a group of animals that exhibit unique developmental features, including radial cleavage, indeterminate fate of the blastopore, and enterocoely. They encompass a wide range of organisms, from sea stars and sea urchins to vertebrates like humans.
Understanding the characteristics and significance of deuterostomes is crucial for comprehending the diversity and evolution of the animal kingdom.
This article will delve into the defining traits of deuterostomes, identify and rectify an incorrect statement about them, and highlight their key differences from protostomes. Furthermore, we will explore the evolutionary significance of deuterostomes and their contribution to the intricate tapestry of life on Earth.
Characteristics of Deuterostomes
Deuterostomes are a group of bilaterally symmetric animals that share unique developmental features. Their name derives from the Greek words “deutero” (second) and “stoma” (mouth), referring to the formation of the mouth during embryonic development.
Unique Developmental Features
- Radial cleavage:Early embryonic cell divisions occur in a radial pattern, giving rise to a hollow ball of cells called a blastula.
- Invagination during gastrulation:The blastula then undergoes invagination, where the cells at one end of the embryo fold inward to form the endoderm, the lining of the digestive system.
- Enterocoely:The coelom, the body cavity, forms by outpouchings from the archenteron, the primitive digestive tube.
Examples of Deuterostomes
- Echinoderms (e.g., sea stars, sea urchins)
- Chordates (e.g., humans, fish, amphibians)
- Hemichordates (e.g., acorn worms)
False Statements about Deuterostomes
Incorrect Statement: Deuterostomes exhibit spiral cleavage during embryonic development.
Correction:Deuterostomes exhibit radial cleavage, not spiral cleavage. Spiral cleavage is a characteristic of protostomes, another major group of bilaterally symmetric animals.
Differences from Protostomes: Which Of The Following Statements About Deuterostomes Is False
Deuterostomes differ from protostomes in several key aspects of embryonic development:
Cleavage Patterns
- Deuterostomes:Radial cleavage
- Protostomes:Spiral cleavage
Gastrulation Processes, Which of the following statements about deuterostomes is false
- Deuterostomes:Invagination
- Protostomes:Invagination or delamination
Coelom Formation
- Deuterostomes:Enterocoely
- Protostomes:Schizocoely or enterocoely
Evolutionary Significance
Deuterostomes are an important group of animals that have played a significant role in the evolution of the animal kingdom.
Diversity and Complexity
Deuterostomes exhibit a wide range of body plans and adaptations, from the radially symmetric echinoderms to the highly complex chordates. This diversity has contributed to their ecological success and the occupation of a wide variety of habitats.
Origin of Chordates
Chordates, including humans, are the most complex group of deuterostomes. The evolutionary origin of chordates from other deuterostomes is a subject of ongoing research, with the formation of the notochord, a flexible rod that supports the body, being a key feature in this transition.
FAQ Compilation
What is the defining characteristic of deuterostomes?
Radial cleavage, indeterminate fate of the blastopore, and enterocoely are the defining characteristics of deuterostomes.
Which of the following is NOT a characteristic of deuterostomes?
Spiral cleavage is not a characteristic of deuterostomes.
What is the difference between deuterostomes and protostomes?
Deuterostomes exhibit radial cleavage, indeterminate fate of the blastopore, and enterocoely, while protostomes exhibit spiral cleavage, determinate fate of the blastopore, and schizocoely.
