Ch. 33 Echinoderms and chordates
Terms in this set (66)
Phylum echinodermata includes:
who are the closest relatives to echinodermata?
Deuterostoma clade includes:
what does echinoderms and chordates share?
-features characteristic of deuterostome mode of development
-such as radial cleavage and formation of the anus from the blastopore
-Their DNA are closely similar
Based on early development, many animals can be categorized as having_
what type of cleavage is found in the protostome development?
-cleavage is spiral and determinate
what type of cleavage is found in the deuterostome development?
cleavage is radial and indeterminate
-With indeterminate cleavage, each cell in the early stages of cleavage retains the capacity to develop into a complete embryo
-Indeterminate cleavage makes possible identical twins, and embryonic stem cells
-You can't know well what it will look like
-cell can develop into anything
-Ex: stem cells
forms during gastrulation and connects the archenteron to the exterior of the gastrula
what is the faith of the blastopore in prostostome development?
the blastopore becomes the mouth
what is the faith of the blastopore in deuterostome development?
the blastopore becomes the anus
Deuterostomes share developmental characteristics:
-Radial cleavage and inderterminate
-Formation of the anus from the blastopore
Deuterostomes are defined primarily by _
what animal phylums have protostome development?
what animal phylums have deuterostome development?
-Chrodates (vertebrates, urochordata, and cephalochordata)
-Sea stars and most other echinoderms are slow-moving or sessile marine animals (no free-swiming and they attach to rocks)
-A thin epidermis covers an endoskeleton of hard calcareous plates
-Echinoderms have a unique water vascular system, a network of hydraulic canals branching into tube feet that function in locomotion and feeding
-Males and females are usually separate, and sexual reproduction is external
what is the meaning of echinoderms?
-You know what will look like since embryo development
-Faith is sealed will only develop into certain tissue
-Ex: skin cells
made of calcium carbonate
water vascular system
-a network of hydraulic canals unique to echinoderms that branches into extensions called tube feet, which function in locomotion and feeding
the tube feet are fill with
suck water into the water vascular system
the sexual reproduciton of echinoderms consists of _
external fertilization of dioecious individuals
what is the symmetry of echinoderms?
-radial symmetry with mutliples of five
Echinoderms have_stage which has_symmetry
how do the echinoderms extend their tube feet?
by first filling them with water originally draw by the madreporite and later is squeezed out of the tube feet provoking the extension of the tube feet
what are the five classes of echinoderms
-Asteroidea (sea stars and sea daisies)
-Ophiuroidea (brittle stars)
-Echinoidea (sea urchins and sand dollars)
-Crinoidea (sea lilies and feather stars)
-Holothuroidea (sea cucumbers)
Sea stars have multiple_radiating from the_
The undersurface of each arm bears_, which attach to substrate by_
-grip substrate with adhesive chemicals
sea stars feed on_(describe the preying and digestion process)
bivalves by prying them open with their tube feet, everting their stomach, and digesting their prey externally with digestive enzymes
sea stars can_(in the case they lost an arm)
regrow lost arms
By a combination of_actions, the tube feet can attach and detach from a substrate
-muscular and chemical
Does the adhesion of sea stars to the substrate result of the tube feet suction or chemicals on them?
Although the base of the tube foot has flattened disk that resembles a suction cup, the gripping action results from adhesive chemicals, not suction
what are the functions of the tube feet?
what does a sea star need to regenerate itself?
-part of the central disk attach to the lost part, even that a single arm was lost it can regrow into a new sea star if it has a part of the central disk to regenerate
-They live on submerged wood
-Its body is disk-shaped
-It has five-sided organization
-The edge of the body is ringed with small spines
-Absorb nutrients through a membrane that surrounds their body
-has a nerve ring and nerve cords radiating from the ring into the arms
secrete digestive juices and aid in the absorption and storage of nutrients
the water vascular system consists of a ring canal in the central disk and five radial canals, each running in a groove down the entire length of an arm. Branching from each radial canal are hundreds of hollow, muscular tube feet filled with fluid
Each tube feet consists of a _
bulb-like ampulla and a podium (foot portion)
How the movement of the tube feet works?
-when the ampulla squeezes, water is forced into the podium, which expands and contracts the substrate. Adhesive chemicals are then secreted from the base of the podium, attaching it to the substrate.
-To detach the tube foot, de-adhesive chemicals are secreted and muscles in the podium contract, forcing water back into the ampulla and shortening the podium
-As it moves, the sea star leaves an observable "footprint" of adhesive material on the substrate M
water can flow in or out of the water vascular system into the surrounding water through the madreporite
the surface of a sea star is covered by_
spines that help defend against predators, as well as small gills that provide gas exchange
A short_runs from the mouth on to the bottom of the central disk to the anus on top of the disk
-Brittle stars have a distinct central disk and long, flexible arms, which they use for movement
-Some species are suspension feeders, while others are predators or scavengers
How do brittle stars move?
primary by lashing their arms in serpentine movements
the base of brittle stars tube foot lacks
the flattened disk found in sea stars but does secrete adhesive chemicals. Thus they use the tube feet to grip to substrates
Sea urchins and sand dollars have no_
arms but have five rows of tube feet
What is the function of the spines of the sea urchins and sand dollars (Echinoidea)?
-Their spines are used for locomotion and protection
sea urchins feed _
on seaweed using a jaw-like structure on their underside
what is the function of the tube feet for Echinoidea species?
function for slow movement
Sea urchins are_and sand dollars are_ (describe shape)
-sea lilies and feather stars
-sea lilies live sessile by their stalk
-feather stars crawl about by using their long, flexible arms
-Use their arms for suspension feeding
-Their mouth is upward with the arms surrounding it
Holothuroidea (describe sea cucumbers)
-Sea cucumbers lack spines
-have a very reduced endoskeleton
-elongated on their oral-aboral axis
-do not look much like other echinoderms
-Have five rows of tube feet; some of these are developed as feeding tentacles
what is the reason that the sea cucumbers, despite they look very different to other echinoderms, are set in this phylum?
because they have 5 rows of tube feet
Phylum chordata consisted of_
-two suphylum of invertebrates as well as hagfishes
Chordates are _symmetrical _(acelomates, pseudolomates, or coelomates?) with _(segmented or non-segmented?) bodies
what are the similarities between chordates and echinoderms? but they evolved separately for at least how many years?
Chordates share many features of embryonic development with echinoderms, but have evolved separately for at least 500 million years
what does each arm of the echinoderms have?
what does keep the shell of a bivalve closed?
the abductor muscles
what is the name of the feeding teeth of sea urchins? what is it made of? how many teeth it has?
-calcium carbonate base
the sea cucumbers to eat what they do?
they expel their gut, for being sticky and poisonous, to catch something