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8 5 3 2 1 Extant How Many Kingdoms? Multicellular Animals Archezoans Slime Molds Archaebacteria Protozoans Green Algae Bryophytes Myxozoans True Fungi Chrysophytes Tracheophytes Euglenoids Brown Algae Bacteria Red algae Extinct Long Time with Prokaryotes only Original Cell
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8 5 3 2 1 Extant How Many Kingdoms? Multicellular Animals Archezoans Slime Molds Archaebacteria Protozoans Green Algae Bryophytes Myxozoans True Fungi Chrysophytes Tracheophytes Euglenoids Brown Algae Bacteria Red algae Extinct Long Time with Prokaryotes only Original Cell
Animal Features • Multicellular Eukaryotes • Heterotrophic Ingestion • Collagen Protein Connections • Nerve and Muscle Tissues • Diplontic (Gametic) Life History • Gametes Oogamous with Flagellated Sperm • Zygote to Blastula, perhaps Gastrulation • Larval metamorphosis into Adult • Ontogeny Recapitulating Phylogeny
Animals Domain Eukarya Kingdom Animalia Phylum Nematoda
http://www.ucmp.berkeley.edu/phyla/ecdysozoa/nematodexssm.gifhttp://www.ucmp.berkeley.edu/phyla/ecdysozoa/nematodexssm.gif http://www.ua.es/dpto/dcarn/fitopatologia/Images/Celegans1.jpg Nematode Body Organization http://creatures.ifas.ufl.edu/nematode/nem_fig1.jpg
Caenorhabditis elegans is a bacteriovorous soil nematode, feeds on E. coli in vitro, is a genetic model organism, its genome is sequenced. http://ucdnema.ucdavis.edu/imagemap/nemmap/Ent156html/nemas/c-elegans.gif http://www.apsnet.org/education/feature/Celegans/Images/fig5.JPG embryo in shell of zygote N=6 XX=hermaphrodite XO=male protandrous Life cycle: 3 days at 20°C vulva anus mouth http://www.esa.int/export/images/Ce_400.jpg
syngamy meiosis protandrous http://nema.cap.ed.ac.uk/Caenorhabditis/C_elegans_genome/celeganslifecycle.jpg
Animals Domain Eukarya Kingdom Animalia Phylum Annelida
Lumbriculus variegatus : California mudworm This is an aquatic oligochaete annelid Mouth feeds in sediments Tail extends toward water surface for gas exchange Body walls nearly transparent for easy observation For example: may count pulses of blood in dorsal vessel http://www.westminster.net/faculty/cobler/Lumbriculus%20variegatus.jpg
clitellum mouth anus http://iris.cnice.mecd.es/biosfera/alumno/1bachillerato/animal/imagenes/nervio/lumbricus.jpg edge of ventral reproductive structures Lumbricus terrestris: Canadian nightcrawler or Earthworm
The earthworm body is fundamentally segmented. Here is a typical segment: Each segment is filled with coelomic fluid, under some pressure, which provides “stiffness.” The segments near the head are specialized for other physiological functions. http://www.mun.ca/biology/scarr/142003_Annelida.jpg
http://www.esu.edu/~milewski/intro_biol_two/lab__12_annel_arthro/images/lumbr_diagr_dissection.jpghttp://www.esu.edu/~milewski/intro_biol_two/lab__12_annel_arthro/images/lumbr_diagr_dissection.jpg Major Organ Systems in an Earthworm Excretory: Reproductive:Male Female Circulatory: Gases, Nutrients, Wastes Digestive: Food Intake Nutrient Absorption Muscular: Movement Dermal: Gas Exchange Nervous: Sensory and Coordination
Characteristics • More than 100 segments • Segments separated by partitions that divide coelom • Segments identical except when specialized and fused • Anterior and posterior ends • Cephalization specialized for burrowing • Head contains sense organs • Circular and longitudinal muscles http://www.student.loretto.org/zoology/phylum_annelida.htm 1 Mouth 2 Prostomium 3 Segment 4 Spermathecal openings 5 Female (oviduct) opening 6 Male (vas deferens) opening 7 Sperm groove 8 Papilla 9 Clitellum (saddle) 10 Paired setae (ventro-lateral) 11 Anus 12 Dorsal surface 13 Ventral surface http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20external%20form.htm
Movement • Setae anchored during movement • Circular muscles contract • Hydrostatic pressure increases in anterior coelomic cavities • Body elongates pushing head forward • Anterior setae grip ground • Longitudinal muscles contract--posterior pulled along • Coelomic divisions allow simultaneous contraction and expansion of segments http://www.student.loretto.org/zoology/phylum_annelida.htm A External view B Section through segment 1 Coelom 2 Circular muscle 3 Cuticle 4 Intestine 5 Dorsal blood vessel 6 Typhlosole 7 Epidermis 8 Nephridium 9 Longitudinal muscle 10 Seta 11 Protractor muscle 12 Retractor muscle 13 Ventral nerve cord 14 Subneural vessel 15 Ventral vessel 16 Septum http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20muscle%20system.htm
Nervous • Sensitive to tough, light, moisture, chemicals, temperature, and vibrations • Light receptors on head and tail--sense direction • Most sense organs and nerves control muscle contractions in individual segments • Pair of ganglia in each segment coordinate movement with adjacent segments • Cerebral ganglion in head controls total body • Ventral nerve cord connects brain with ganglia http://www.student.loretto.org/zoology/phylum_annelida.htm 1 Anus 2 Intestine 3 Cerebral ganglion 4 Prostomium 5 Mouth 6 Nerve collar 7 Segmental ganglion 8 Pharynx 9 Esophagus 10 Segmental nerve 11 Crop 12 Gizzard 13 Ventral nerve cord http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20digestive%20and%20nervous%20systems.htm
Feeding • Feed on organic matter in soil • Digest organic matter • Wastes and undigested soil eliminated as casting • Loosens and aerates soil • Digestion • Soil sucked in by pharynx -> esophagus -> crop (storage) -> • gizzard (grinds soil releasing organic matter) -> • intestine (nutrients absorbed) 1 Anus 2 Intestine 3 Cerebral ganglion 4 Prostomium 5 Mouth 6 Nerve collar 7 Segmental ganglion 8 Pharynx 9 Esophagus 10 Segmental nerve 11 Crop 12 Gizzard 13 Ventral nerve cord http://www.student.loretto.org/zoology/phylum_annelida.htm http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20digestive%20and%20nervous%20systems.htm
Circulation • Transport oxygen, nutrients, and wastes • Flow of blood toward posterior via ventral blood vessel • Flow of blood toward anterior via dorsal blood vessel • 5 pair of aortic arches link vessels near anterior • Smaller vessels branch into segments • Contraction of ventral vessel and aortic arches forces blood through body http://www.student.loretto.org/zoology/phylum_annelida.htm 1 Anus 2 Dorso-subneural vessel 3 Intestine 4 Dorsal vessel 5 Hearts (aortic arches) 6 Mouth 7 Ventral vessel 8 Subneural vessel http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20circulatory%20system.htm
Gas Exchange • Lack gills or lungs--oxygen and carbon dioxide diffuse across skin • Requires moist skin, thin cuticle, mucus secretion…limits habitat! • Excretion • Elimination of nitrogen wastes • Long tubules (nephridia) excrete wastes • Coelomic fluid enters nephridium through ciliated funnel opening • Some water reabsorbed by blood • Remaining fluid excreted through ventral pores http://www.student.loretto.org/zoology/phylum_annelida.htm A External view B Excretory system (nephridium) C-D Reproductive system C Lateral view D Dorsal view 1 Nephrostome 2 Septum 3 Ciliated tube 4 Bladder 5 Nephridiopore 6 Body wall http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20excretory%20and%20reproductive%20systems.htm
Reproduction • Hermaphrodites--cannot self fertilize • Worms join head to tail • Form mucus coat around bodies--each inject sperm into mucus • Sperm move to seminal receptacle • Eggs move through oviducts to female genital pore • Clitellum secretes mucus and chitinous sheath • Worm wiggles to slip off sheath • Eggs and sperm join A External view B Excretory system (nephridium) C-D Reproductive system C Lateral view D Dorsal view 1 Nephrostome 2 Septum 3 Ciliated tube 4 Bladder 5 Nephridiopore 6 Body wall 7 Seminal vesicle 8 Testis 9 Egg sac 10 Male opening 11 Female opening 12 Oviduct 13 Ovary 14 Sperm duct (vas deferens) 15 Opening to sperm-receiving sac 16 Sperm-receiving sac (spermatheca) http://www.student.loretto.org/zoology/phylum_annelida.htm http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20excretory%20and%20reproductive%20systems.htm
http://sps.k12.ar.us/massengale/images/worms_mating.jpg http://biog-101-104.bio.cornell.edu/BioG101_104/tutorials/animals/worm_stuff/worm_ventral.html http://sps.k12.ar.us/massengale/earthworm_dissection.htm
flagellum collar cell body http://192.171.163.165/pil/Choanoflagellate_spp..jpg http://ebiomedia.com/downloads/sponges.pdf Animals probably evolved from a flagellated protist similar to the choanoflagellates One step in this evolution is to become colonial. Here are the choanocytes of one of the simplest of sponges. Basically the most primitive animals. Of course the other required step is to eliminate the chloroplasts of the choanoflagellate (Chrysophyta!).
spongocoel Planarian gastrovascular cavity Nematode pseudocoelom digestive tract Annelid coelom Evolution of Body Organization Sponge, Cnidarian Ectoderm Endoderm Mesoderm 2-layered 3-layered Acoelomate Pseudocoelomate Coelomate
Development or Evolution? cleavage zygote blastula 2-layered acoelomate body plan
Cnidarians Protostome Phyla archenteron Deuterostome Phyla (except vertebrates) blastopore mouth mouth anus Platyhelminthes Nematoda Annelida Mollusca Arthropoda Origin of Mesoderm Echinodermata Hemichordata Chordata blastocoel
Mollusca Annelida Platyhelminthes Echinodermata Rotifera Arthropoda Hemichordata Nematoda Porifera Cnidaria eumetazoa (true tissues) deuterostomia bilateria coelomates loss of chloroplast, colonial organization radiata acoelomates protostomia pseudo-coelomates parazoa Extant The Animal Clade Chordata This cladogram omits several smaller animal phyla! Ancestral Choanoflagellate