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Colors in this species can range from orange to brown. This variation depends on environment; the color of the sea cucumber depends on the sand color of the organism's habitat.

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All organism in the species are red but the banding around them can be different. The possible colors are white, pink, yellow, or dark red. The different colors are used for camouflage or warning coloration against predators.

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The color range varies from light to dark purple and their spines can be several colors: red pink, light/dark purple, maroon, or brown. The color of a sea urchin can be influenced by their environment. By having a variation of color, sea urchins in different locations can be camouflaged. Two pigments control their color: Carotenoid pigment (controls red, orange, yellow)  and naphthoquinone pigment (controls purple, green, and red).

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This tree shows the ancestral history connecting chordates and echinoderms. Their common ancestor had an internal skeleton, which is the major anatomical similarity that connects these distinct groups of organisms. After evolving from the ancestor with an internal skeleton Chordata and Echinodermata diverged and diversified.

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Echinoderms general information- text book (Modern Biology Holt, Rinehart and Winston)

Sea Urchin- http://animaldiversity.org/accounts/Strongylocentrotus_franciscanus/

Sea Star- http://animaldiversity.org/accounts/Crossaster_papposus/

Sea cucumber- http://animaldiversity.org/accounts/Isostichopus_badionotus/

Reproduction- http://www.oceaninn.com/wildlife/echinoderms.htm

Eating- https://www.britannica.com/animal/echinoderm

Fossils-

http://www.ucmp.berkeley.edu/vendian/arkarua.html

https://museumvictoria.com.au/discoverycentre/infosheets/marine-fossils/echinoderms/

http://www.thefossilforum.com/index.php?/gallery/image/21576-temnocidaris-stereocidaris-sceptrifera-mantel1822-upper-campanian-charente-maritime-france/

https://www.fossilera.com/fossils/jurassic-starfish-brittlestar-lyme-regis-england

Homologous Structure- http://www.earthlife.net/inverts/echinodermata.html

Embryology- https://evodevojournal.biomedcentral.com/articles/10.1186/2041-9139-3-17

Adaptive Radiation-

http://www.fossilmuseum.net/Tree_of_Life/Phylum-Echinodermata.htm

http://www.nationalgeographic.com/science/prehistoric-world/permian/

Divergent Evolution-

https://www.scientificamerican.com/article/see-change-rapid-emergence/

Chromosomal comparison-

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3308324/

Karyotype-

http://digitalcommons.wcupa.edu/cgi/viewcontent.cgi?article=1016&context=bio_facpub

internal bilateral symmetries or asymmetries- http://images.pcmac.org/SiSFiles/Schools/OR/SeasideSchoolDistrict/SeasideHigh/Uploads/Presentations/CnidariaCtenophora-2014.pdf

DNA analysis-

http://www.livescience.com/1103-surprise-cousin-sea-urchin.html

Chromosomal analysis

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3308324/

Protein Analysis-

https://www.ncbi.nlm.nih.gov/pubmed/11080371

Phylogenetic tree-

http://biologydiva.pbworks.com/w/page/14797002/Zoology%20Chapter%2032

Microevolution-

https://www.newscientist.com/article/dn23358-sea-urchins-evolving-to-cope-with-ocean-acidification/

https://blogs.scientificamerican.com/artful-amoeba/the-sea-cucumber-that-became-a-jellyfish-video/

http://www.fossilmuseum.net/Tree_of_Life/Phylum-Echinodermata.htm

Trait-

http://www.sheppardsoftware.com/content/animals/animals/invertebrates/starfish.htm

Natural Selection-

http://www.snorkelstj.com/three-rowed-sea-cucumber.html

Geographic isolation-

https://books.google.com/books?id=VB6KrdOiHZ0C&pg=PA23&lpg=PA23&dq=geographic+isolation+of+echinoderms&source=bl&ots=ztdec7MZ9d&sig=qK-gg6OmnFbUBa4HY3ygQQa8qYM&hl=en&sa=X&ved=0ahUKEwiPwsyD15fUAhXISyYKHcsQDG0Q6AEIPDAG#v=onepage&q=geographic%20isolation%20of%20echinoderms&f=false

Reproductive Isolation-

http://www.bio.miami.edu/dana/dox/reproductive_isolation.html

Punctuated equilibrium-

https://www.scientificamerican.com/article/see-change-rapid-emergence/

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Three-rowed sea cucumbers have a unique way of defending themselves. When threatened by a predator the three-rowed sea cucumber expel their internal organs through its anus as a way to feed and satisfy its prey. Later the cucumber is able to regenerate its organs. The organisms who cannot regenerate as fast tend to be eaten more often. This is an example of directional evolution because the sea cucumbers who regenerate their organs faster tend to outlive those who regenerate more slowly. In this case the extreme case (very quick regeneration) is more successful in survival than the average and the opposite extreme form of the trait.

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These sea stars are one of the top predators in their food chain; however the organisms with more arms have an advantage. They are able to move quickly and efficiently, escaping possible predators. This is an example of  directional evolution because the organisms with low and average amounts of arms are being eaten more often than those with the most possible arms. The extreme trait (more arms) is more successful in survival than the average and the other extreme form of the trait.

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Decent with modification is shown through the phylum echinodermata because every organism in this group has radial symmetry. This special characteristic must have come from a common ancestor and later on thousands of new species evolved. Every species in this phylum has unique and diverse qualities but they had to of evolved from one species which gave them all radial symmetry.

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The crinoid gardens after their near extinction they were able to diversify and regenerate their population. Unfortunately, in the cenozoic era (65 million years ago) they faced another major decline in population, which caused another threat of extinction. In order to adapt and prevent extinction they were able to evolve and move to deeper waters. Prior to this evolution crinoids could not survive in deep waters or they would have move there the first time they faced extinction. The crinoids had to evolve and adapt to a new kind of environment to keep their population alive.

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The Pelagothuria natatrix is a sea cucumber that has evolved to avoid the sea floor. Most sea cucumbers live on the ocean floor which is where they get their food. This species has evolved into a jellyfish-looking sea cucumber which floats in the water. They also evolved into a sausage shape and they evolved anal teeth to keep other organisms out. This evolution occurred due to lack of food sources on the ocean floor and increasing amounts of predators.

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The purple sea urchin has adapted to increasing acid levels of the ocean in response to climate change and fossil fuel usage. To adapt themselves in more acidic waters the sea urchins have changed their frequency of genes related to metabolism, growth and the movement of ions into and out of the cell. Researchers believe this is caused by natural selection.

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Three- Rowed Sea Cucumber (Isostichopus badionotus)

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Three- Rowed Sea Cucumber (Isostichopus badionotus)

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Random Mating- This species does not know or care who they mate with.
Spawn in the late winter early spring months. Parents are not involved in their offspring after spawning. This organism can also produce an offspring by cutting itself in two and regenerating.

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Random Mating- This species does not know or care who they mate with. Spawning and external fertilization in late winter months.

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Red Sea Urchin (Strongylocentrotus franciscanus)

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Red Sea Urchin (Strongylocentrotus franciscanus)

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Random Mating- This species does not know or care who they mate with. Every organism mates with several others (male and female- polygynandrous). Red sea urchins in warm areas spawn all year while those in cooler location only spawn from June-September. Sexual maturity is around 2 year old and there is no known rate of spawning.

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Crinoid gardens used to live in shallow waters in the Paleozoic era, they faced problems almost causing extinction. Only a small amount survived during the Triassic period, around 250 million years ago. During the Mesozoic era the species went through adaptive radiation. The few survivors began to develop more flexible arms through evolution, which helped them survive. This allowed them to evolve separately into many new species which regenerated the crinoid garden population which was no longer threatened by extinction. The extinction was during the Permian period, the largest mass extinction on earth. Climate problems began when the super continent Pangaea lead to extreme cold in the south and extreme in heat in the north. This along with other environmental factors lead to the extinction.

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Common sun stars are very mobile creatures and can live spread out from each other but not much group migration occurs. Individual migration could potentially impact gene flow because these sea stars spawn. If they are very spread out spawning many not lead to successful fertilization. However, when close together, sea stars along with other spawners have a lot of gene flow. This is because through spawning there is no selection in who you mate with. By “shooting out” gametes the only thing parents want if for them to come in contact with the opposite gamete.

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This example of reproductive isolation does not have much of a harmful impact on the population of red and purple sea urchins. The two organisms live in the same environments and although they cannot reproduce with each other, organisms of the same species are still able to reproduce. Populations are still growing for each organism. The geographic isolation is affecting the population of the two sea urchin species by allowing them to evolve separately. Each population continues to grow after isolation they just no longer grow together.

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The Strongylocentrotus franciscanus and Strongylocentrotus purpuratus face prezygotic isolation. Both organisms are spawners but their gametes are chemically unable to produce zygotes. The two species live in the same rocky habitat along the western coast of America.

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Eucidaris, Diadema, and Echinoderma species have been geographically isolated by the Isthmus of Panama. The isolation had lead to the evolution of two new species: the temnopleurus toreumaticus and the temnopleurus hardwickii . Two species were able to evolve separately due to their different environments. Both lived through different experiences giving both species their own evolutionary path.

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Divergent evolution occurred in starfish about 6,000 years ago. The diverged species are Cryptasterina pentagona and Cryptasterina  hystera. The species are very similar physically (plump body, green and blue color), and they have very similar genes because they share the same parent. However, there main difference is in their mating/reproductive habits. The Cryptasterina pentagona mates through spawning, gametes meeting in the water and larvae forming outside the female star fish. Males excrete sperm and females eggs, the gametes are fertilized in the water. The  Cryptasterina  hystera (hermaphrodites) is self-fertilizing and the embryo grows inside the parent.

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The divergent evolution of the Cryptasterina pentagona and Cryptasterina  hystera proves punctuated equilibrium is at work in the Phylum Echinoderm. Echinoderms do not change all that often but when they do it occurs at a rapid pace. Researchers say ”the two sea star species would win in an evolutionary race”.

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Both species have the same amount of chromosomes and their sex chromosomes are very similar. They are the same the chromosome number (21) and they have one long chromatid and one short one for chromosome 21. This shows the species must have come from a similar ancestor due to their almost identical karyotypes. Red and Green Sea Urchins most likely have very similar evolutionary history.

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Scientists examined DNA sequences of 273 base pair regions of 134 adult Red Sea urchins (Strongylocentotus fraciscanus). By looking at DNA base pair regions they studies protein coding regions They are studying bindin locus, a sperm recognition protein which controls the interaction of gametes. The bindin locus is a polymorphic gene; 14 alleles control this protein. This shows there is moderate diversity in this protein; every sea urchin has a unique bindin locus. Scientists discovered the protein polymorphic because of  random mutations and genetic drift.

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The purple sea urchin (Strongylocentrotus purpuratus) has 23,300 genes made from 814 million letters of DNA code. 7,077 of these genes are shared with Homo sapiens. These sea urchins have many defense genes giving them an immune system much like humans. The shared genes show millions of years ago humans and sea urchins were related through a common ancestor, where both species obtained the same 7,077. These shared genes in both sea urchins and humans contribute to both species’ strong immune systems.

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Purple Sea Urchin (Strongylocentrotus purpuratus) 

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Purple Sea Urchin (Strongylocentrotus purpuratus) 

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The purple sea urchin (Strongylocentrotus purpuratus) and the green sea urchin (Strongylocentrotus droebachiensis) are two of the few echinoderms with a fully sequenced genome because of the complexity of chromosomal analysis within the phylum.

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Not much chromosomal analysis can be done with echinoderms because their chromosomes are extremely small and tightly clustered. Different research has reported different numbers of chromosomes in members of the same species; therefore the true number of chromosomes is unknown. However the average is believed to be around 36-46 diploid chromosomes. With the little research done scientists have concluded that echinoderms have sex chromosomes that can identify an organism as male or female.  Each of the 5 echinoderm classes have different amounts of chromosomes ranging around 36-46 chromosomes. Different amounts of chromosomes mean each class has a different amount of genetic information leading to variation within the phylum. Some research has discovered the Hox Gene on echinoderm chromosomes which is what caused radial symmetry.

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Hox genes located on chromosomes in clusters allow echinoderms to have their symmetrical shape. Hox genes control the organization of the organism's body parts and they are placed differently on different types of echinoderms; however, they allow for all echinoderms to have symmetry.

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The sea star and sea cucumber both develop a section of fated cells which contain erg, ets1, gata4/5/6, foxn2/3, tbr, tgif and gata1/2/3 in the embryo.  These fated cells must have derived from a common ancestor, which is how they both develop this structure in embryonic development. Researchers suggest this "mesodermal domain" derived from a common ancestor between sea stars and sea cucumbers around 450 million years ago.

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Tube feet are a homologous structure that in the past were used for motion and collecting food. The use remains the same in present time, but some organisms use them for more than their basic functions. They are a part of the organisms water vascular system.

In Strongylocentrotus franciscanus tube feet are used to chemically detect food, for movement, or to stay in one place.

In Crossaster papposus tube feet are used to catch prey by extending them, essentially growing taller and gaining height on their food.

In Isostichopus badionotus tube feet are used for motion and they are their only apendages.

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Each fossil has radial symmetry (a central access with “limbs” coming out of it). The majority of echinoderms today have 5 limbs; however, a select few have more. The fossil Stereocidaris bistriata could be an ancestor of the Crossaster papposus who can have far more than 5 “limbs”. The Crossaster papposus must have evolved from an organism with limbs in similar amounts as itself.

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The fossils show evidence of evolution by proving all echinoderms shared a common ancestor. This is shown through the radial symmetry present in each fossil; meaning all limb-like structures come from a central axis. This unique trait most likely came from one species, who later evolved into the thousands of diverse species in the phylum echinodermata

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Asterocidaris bistriata- 170 million years old, from the Bajocian age.

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Palaeocoma egertoni- 190 million years old, from the lower Jurassic period.

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Temnocidaris sceptrifera- 80 million years old,  from the Cretaceous period.

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Lovenia bagheerae- 8 million years old , from the late Miocene age.

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Helicocrinus plumosus-415 million years old, from the late Silurian period.

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Eoactis stachi- About 420 million years old, from the late Silurian period.

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The taxonomic classification of the echinoderms show that each species in the phylum is very diverse. By only having a common kingdom and phylum shows how the organisms studied are very unique because the more common classifications mean a closer relationship between organisms.

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Scientific Name-  Isostichopus badionotus
Location-  Northern Pacific coast of South Africa and close to the Galapagose Islands and Venezuela.

Habitat- These sea cucumbers live in shallow and calm waters.
External Characteristics- These organisms have a cucumber shape, no limbs besides tube feet, mainly solid in color ranging from orange to brown, covered in dark wart-like dots, big mouth with bushy tentacles. Average .1-.3 meters in length.
Internal Characteristics- These sea cucumbers have no spine but they have light and touch receptors.

Behavior- Breed in late winter and early spring. Live individually and spend most of their time feeding. Uses tentacles to eat anything off the ocean floor. They must eat a lot because ocean floor sediments have little nutrients so they need to eat all the time to make sure they get proper nutritious foods.  They are nocturnal creatures
Natural Variation- .07- 6.56 ft in length

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Scientific Name-  Crossaster papposus
Location- North Pacific and Atlantic Coast. Gulf of Maine and East port.

Habitat- Rock bottoms as deep as 330 m deep and they can sustain strong sunlight.

External Characteristics- 8-14 inches in diameter and can have 8-14 arms which are one half the radius of the sea star. They have a white underside and the top is white, pink, or dark red. Top side is covered with pseudo paxillae (“fine spines” on the tissue). They also have a bare mouth and tube feet with suckers. They can regrow limbs if they are cut off.

Internal Characteristics-  bilateral symmetries
Behavior- As the common seastar grows they travel to deeper waters. They produce larvae in late winter. High up in its food chain, meaning they do not have too many predators. To capture their prey the seastar uses its tube feet to physically raise its body and then jump on its prey and completely cover it. Common sea stars have chemoreceptors which they use to sense prey. It is a top predator, who eats urchins and invertabres. They are nocturnal creatures and they also live and feed in groups.
Natural Variation- diameter can be 8-14 inches and can have 8-14 arms

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Scientific Name-Strongylocentrotus franciscanus
Location- Pacific coast of North America (Baja California, Isla Cedros, Gulf of Alaska) and the Northern Coast of Japan.
Habitat- rocky reefs in between tide marks (underwater at high tide above water at low tide).
External Characteristics- Round shape, chalky shells called “tests” all covered by a thin layer of tissue. Red sea urchins can grow up to 19 cm. Shell color can be in between light and dark purple, spikes can be red, pink, purple, maroon, or brown and can be as large as 8 cm (used to scare away predators and for movement).
Internal Characteristic- Water vascular system allowing tube feet to extend. Tube feet are normally red. Red sea urchins have an “Aristotle’s Lantern” which is a feeding structure of urchins, located on the mouth surface and it has five teeth. These urchins have a gill-like internal structure which helps with movement and eating.
Behavior- Red Sea Urchins live in schools. The schools stay in the same relative location when food is plentiful they move more when there is less food. Red sea urchins eat with their “Aristotle’s Lantern” and are able to hunt for food in groups and use their tube feet to move. They eat bull kelp, giant kelp or if no food is available they absorb their own tissue. To escape from predators such as horn sharks and spiny lobster, small red sea urchins hide under larger urchins to stay out of sight. They are nocturnal creatures
Natural Variation-life span 100-200 years

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External- Echinoderms have radial symmetrical bodies which means body parts extend from one central region. Echinoderms have no cephalization, which means they do not have a head or a central location for sense organs. These organisms have spiky skin and pedicellariae which keep the skin clean from sea debris, two rows of tube feet under each limb, and flattened bodies. Their mouths are located on their undersides and their anuses are located on their topside. Echinoderms range from around 10 cm to 2 meters.

Internal- Echinoderms have endoskeletons made up of tiny bones called ossicles, which poke the skin giving the organisms their spiky texture. They also have a water vascular system, which is an internal system of water canals. Echinoderms have a nervous system made up of nerve rings around the mouth, radial rings that run down each arm, and no brain.

Tube Feet- These structures are used for movement, respiration, eating, and elimination. They are connected to the water vascular system which is how they can move. Tube feet have an internal muscle called ampulla and when they contract water from the vascular system rushes to the structures allowing the feet to extend and causing the external muscle called the podia to act as suction cups.

Behavior- Echinoderms typically are both sessile and motile. The podia of their tube feet allow them to suction themselves in one place, and the tube fee also allow the organism to move when obtaining food. Most echinoderms reproduce outside the body through spawning; however, few species can produce asexually. In echinoderms reproduction can also occur through fragmentation, which is when the part of the organism is cut off the severed organism can regenerate lost body parts. In some cases, if enough of the organism was cut both severed parts can regenerate, creating a whole new organism.  When feeding most echinoderms use their arms and tube feet to capture food. Most of these organisms are filter feeders and eat whatever they can find.

Habitat- Echinoderms are marine animals and can live in many different types of habitats. Echinoderms have been found in saltwater environments around the world. Some echinoderms live in shallow waters all across the globe in warm or cold waters. In shallow shores organism can bury themselves under mud or sand, or they lay on top. Some even live in the deep sea. And some echinoderms even attach themselves to other organisms.