Animalscaretips
- How did echinoderms evolve?
- Do echinoderms have growth rings?
- Which echinoderms are most developed?
- Do echinoderms have direct or indirect development?
- When did echinoderms emerge?
- Why are echinoderms categorized together?
- How do the echinoderms reproduce?
- Are echinoderms Acoelomate?
- Why are echinoderms the most advanced group of invertebrates?
- Do echinoderms have an exoskeleton?
- Do echinoderms follow a pattern?
- How does the body symmetry of echinoderms change during development?
- What is unique about echinoderms?
How did echinoderms evolve?
Echinoderms evolved from bilaterally symmetric animals exhibiting fivefold radial symmetry in portions of their body at some stage of life. ... While echinoderms are known from the Cambrian on, the Vendian period has a few soft-bodied fossils that are putative echinoderms or their ancestors.
Do echinoderms have growth rings?
Even though plate rings in echinoderms, especially in echinoids, have been studied for decades, very little is known about the mechanisms that underlie their addition and growth patterns. ... fabricii is not the result of differences between rapid and slow growth periods reported in other echinoderms [2].
Which echinoderms are most developed?
The echinoderm coelom is well-developed, and it forms two major cavities during development. One cavity becomes the actual coelom that houses internal organs, while the other develops into the water vascular system.
Do echinoderms have direct or indirect development?
When sexual reproduction occurs, the resulting eggs go through either direct or indirect development. When indirect development occurs, the fertilized eggs of echinoderms will develop into larvae known as planktonic larvae. In most cases, this stage occurs when the fertilized egg consists of a lower yolk volume.
When did echinoderms emerge?
Beginning with the dawn of the Cambrian Period (542 million to 488 million years ago), echinoderms have a rich fossil history and are well represented by many bizarre groups, most of which are now extinct.
Why are echinoderms categorized together?
Echinoderms and chordates are grouped together because they both are deuterostomes, or animals that grow radially, have a blastopore that develops...
How do the echinoderms reproduce?
Asexual reproduction in echinoderms usually involves the division of the body into two or more parts (fragmentation) and the regeneration of missing body parts. ... In some asteroids fragmentation occurs when two groups of arms pull in opposite directions, thereby tearing the animal into two pieces.
Are echinoderms Acoelomate?
Members of the phylum Echinodermata are coelomates. The term coelom comes fromt eh Greek koiloma which means cavity Acoelomates are invertebrate...
Why are echinoderms the most advanced group of invertebrates?
What evidence is there that Echinoderms are the most advanced group of invertebrates? Even without a brain, they have a nerve ring that responds to light and touch. How do the tube feet of an Echinoderm help the animal? They help the animal move by extending and withdrawing.
Do echinoderms have an exoskeleton?
Although these spines may look like components of an exoskeleton at first glance, echinoderms do not have an exoskeleton. Instead, the spines are extensions of an internal endoskeleton. The endoskeleton is composed of calcium carbonate plates and spines that are actually covered by a thin layer of epidermis (skin).
Do echinoderms follow a pattern?
Echinoderms do not follow this pattern. ... The bodies of echinoderms are made of tiny, hard calcium-based plates. The plates are often spiny and always covered by a thin skin. Because the echinoderm skeleton is on the inside, it is called an endoskeleton.
How does the body symmetry of echinoderms change during development?
Bilateral symmetry means the organism can be cut right down the middle and be split into two equal halves. The echinoderm ancestry later developed radial symmetry as it was thought to be more advantageous to the species.
What is unique about echinoderms?
Echinoderms possess a unique ambulacral or water vascular system, consisting of a central ring canal and radial canals that extend along each arm. Water circulates through these structures and facilitates gaseous exchange as well as nutrition, predation, and locomotion.
