biol 11 lesson 5 april 15 - ch. 29 echinodermata
TRANSCRIPT
Homework from last Homework from last class:class:Complete the Phylum Facebook project
Read Ch. 29-1 Echinodermata
Phylum Phylum Echinodermata:Echinodermata:EchinodermsEchinodermsChapter 29:Echinodermatapp. 637-644
BBC Life: Time Lapse of Sea BBC Life: Time Lapse of Sea StarsStars http://www.youtube.com/watch?
v=HG17TsgV_qI
Phylum Echinodermata - echino = “spiny”, dermis = “skin”
Radial symmetry (often pentaradial)o However, larvae have bilateral symmetry
3 cell layers (ectoderm, endoderm, mesoderm)
Internal skeleton (endoskeleton) – plates of CaCO3
Water vascular system with tube feet
All marine
Very ancient group unlike those of any other living group
Introduction to Introduction to EchinodermsEchinoderms
Echinoderms appear to be related to chordates (vertebrates).
Scientists think this because:
1.Echinoderm larvae are similar to certain chordate larvae.
2.Echinoderms have an endoskeleton (not exoskeleton).
3.Their pattern of embryonic development is same as for chordates (radial cleavage – anus develops before mouth)
◦ Mollusk, annelid, and arthropod embryos undergo spiral cleavage - mouth develops first.
Classes of EchinodermsClasses of Echinoderms1) Class Asteroidea: ex: star fish (aka sea stars)• Often pentaradial, usually predatory• Creep along using tube feet
2) Class Ophuroidea: ex: brittle stars• Largest group• Often pentaradial• Filter feeders or detritus feeders• Flexible arms
3) Class Echinoidea: ex: sea urchins, sand dollars• Some with protective spines• Usually grazers (eat algae)
Classes of EchinodermsClasses of Echinoderms4) Class Holothuroidea: ex: sea cucumbers• Usually detritus feeders (aka scavengers)• Radial symmetry• Often live in ‘herds’ on ocean floor
5) Class Crinoidea: ex: sea lilies and feather stars• Long, feathery arms• Sessile• Filter feeders• Rare today but lots of fossils of them
Form and Function of Form and Function of EchinodermsEchinodermsRepresentative member: sea star
Digestive system:• Starfish pry open prey (ex: bivalves) with their tube
feet, then flip stomach inside out into the prey and secrete enzymes to digest the tissue. Then they suck their stomach back in.
oral surface (location of mouth) is on bottom
aboral surface (location of anus) is on top
Scavengers (ex: sea cucumbers)
Filter feeders (ex. sea lillies)
Respiratory system: Tube feet for O2/CO2
exchange Some species have
“skin gills”
Circulatory and Excretory systems: No separate systems for these (tube feet and skin gills
are all over the body and take care of O2/CO2 exchange and metabolic waste removal
Nutrients (food) are distributed by digestive glands, not by blood (there is no blood)
Sea star tube feet
Adult sea star internal anatomy
Nervous system: Primitive No head Nerve ring surrounds mouth; radial nerves in
arms Sea stars have eyespots at tip of each arm Statocysts (to tell which side is up)
Musculoskeletal system:
• Instead of muscles, sea stars have a unique water vascular system (hydraulics)
• Water vascular system consists of:ring canal: forms a circle around digestive system
radial canals: canals which extend into each arm
tube feet: suction-cuplike structures connected to the water vascular system
madreporite (sieve plate): opening used to filter water into the water vascular system
(see p. 639)
• Sea star endoskeleton is composed of protective plates made of CaCO3 (for protection, not involved in movement).
• Some echinoderms can walk around on their arms (ex: brittle stars) or crawl (ex. sea cucumbers)
Reproductive system:• Usually separate sexes
• “Broadcast method” - sexual reproduction
• Regeneration – asexual reproduction
• Many species can regrow lost parts
Sea Star Renegerationhttp://www.youtube.com/watch?v=f7cXeWxxfD4
Sea stars control many populations (they are important predators)
Sea urchins often control algae populations
Both sea stars and sea urchins have been known to upset the ecology of an area
Sea urchins are used in embryological research (large eggs)
Drug research (ex. anti-viral and anti-cancer drugs)
Some are edible delicacies (ex. sea urchin eggs and sea cucumbers)
Ecology of EchinodermsEcology of Echinoderms
Demo – Sea Star Dissection
Homework for next class:Homework for next class: Complete Echinoderms and Chordates Worksheet –
1st side only (Section 29-1)
Complete sea star colouring diagram (include a key)
Work on 15 Ch. 29 Echinodermata cue cards
◦ Due Thursday, April 21 (Ch. 26-29 Invertebrate Test day)
Have a great
weekend!
Works CitedWorks CitedImages taken from the following
sources:http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20102/bio%20102%20lectures/animal%20diversity/protostomes/lophotrochozoans/lophotrochozoans.htm
http://myfishtanks.info/fish-profile/saltwater-invertebrate-profiles/brittle-star-tiger-striped-serpent-seastar/
http://www.iloverubberstamps.com/catalogpage2.html
http://clipart.usscouts.org/library/us_fish_and_wildlife_service/fish/
http://jklsciencelab.weebly.com/starfish-dissection.html
http://www.topnews.in/law/general/featured?page=5816&destination=taxonomy
http://www.easyvectors.com/browse/other/sea-cucumber-clip-art
http://etc.usf.edu/clipart/49800/49826/49826_sea_lily.htm
http://www.australiascoralcoast.com/en/Things_to_see_and_do/Nature_and_wildlife/Pages/Nature_and_wildlife.aspx
http://www.picassomio.es/crown-of-thorns-starfish-poster-2386298.html
http://en.wikipedia.org/wiki/File:Sea_urchin_tests.jpg
Works CitedWorks CitedImages taken from the following
sources:http://www.kadamsphoto.com/nature_recreation/seashells_mollusks.htm
http://www.interesting-facts.biz/category/marine-animals-facts/page/3
http://megashare.info/watch-the-office-season-7-episode-14-online-TWpVM01nPT0
http://aspire.mlml.calstate.edu/aspire04/updates/nov/25nov/nov25.htm
http://siera104.com/bio/echin.html
http://www.naturebridge.org/headlands/blog/rachel-loud/creature-month-sea-stars
http://bonneeats.com/?p=270
http://www.mahingakai.org.nz/mahinga-kai-species/kina