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Animal Relationships Metazoa = Animalia Eumetazoa Bilateria

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Animal Relationships Metazoa = Animalia Eumetazoa Bilateria On the move, and Land Ho! 1. Enter answer text... Animal relationships Metazoa = Animalia Eumetazoa Bilateria Porifera Radiata (sponges) Cnidaria Themes: 1) Mobility 2) Land (again) Kingdom Animalia Multicellular, eukaryotic, and heterotrophic Porifera - Examples of early animals ! No true tissues ! Only a few cell types "Some totipotent ! Filter feeders "Full of holes " Create current with choanocytes See 32.10 #Very similar to choanoflagellates! Animal relationships Metazoa = Animalia Eumetazoa Bilateria Porifera Radiata (sponges) Cnidaria Themes: 1) Mobility 2) Land (again) Kingdom Animalia Multicellular, eukaryotic, and heterotrophic Eumetazoa ! Diploblastic ! Two cell layers "Endoderm (inside) "Ectoderm (outside) ! E.g. Cnidarians "Jellyfish, anemones, corals See Fig. 32.2 Eumetazoa ! Diploblastic ! Two cell layers "Endoderm (inside) "Ectoderm (outside) ! E.g. Cnidarians "Jellyfish, anemones, corals Eumetazoa ! Diploblastic ! Two cell layers "Endoderm (inside) "Ectoderm (outside) ! Gastrulation ! Cnidarians "Jellyfish, anemones, corals Cnidaria - Diploblastic animals ! Have a nervous system! ! Mobility! ! Radially symmetrical "Not very directional See Fig. 32.7 Animal relationships Metazoa = Animalia Eumetazoa Bilateria "Porifera" "Radiata"Cnidaria (sponges) Eumetazoa Gastrulation Nervous system, synpases Radial Symmetry Animal relationships The ctrouble with Ctenophores ! Beautiful, and way cool ! Superficially similar to Cnidarians ! Quite complicated, in some ways like Bilaterians Metazoa = Animalia ! Have been a problem Eumetazoa Bilateria phylogenetically for a long "Porifera" Cnidaria"Radiata" time! (sponges) Eumetazoa Gastrulation Nervous system, synpases Radial Symmetry Animal relationships The ctrouble with Ctenophores ! No buts about it, the butthole is one of the finest innovations in the past 540 million years of animal evolution. The first animals that arose seem to have literally had potty mouths: Their modern-day descendants, such as sea sponges, sea anemones, and jellyfish, all lack an anus and must eat and excrete through the same hole. Once an independent exit evolved, however, animals diversified into the majority of species alive today, ranging from earthworms to humans. Bilateria - Origins and diversification ! The Cambrian Explosion ! Most modern phyla appear in only 40 million years Animal relationships Metazoa = Animalia Eumetazoa Bilateria "Porifera" "Radiata"Cnidaria (sponges) Eumetazoa Gastrulation Nervous system, synpases Radial Symmetry Bilateral symmetry and Cephalization ! Cephalization "Sense organs in front Bilateral symmetry and Cephalization !Cephalization !Bilateral symmetry "Direction! Two Great Branches of the Bilaterian Tree ! Protostomes "E.g. Annelids, Arthropods, Molluscs ! Deuterostomes "E.g. Chordates Protostomes: Annelida ! Segmentation "Can operate segments independently "Redundancy See 46.18 Protostomes: Arthropoda ! Extremely diverse "Aquatic and terrestrial ! Segmentation "Jointed Skeleton #External = Exoskeleton #Jointed skeleton convergent with vertebrates "Redundancy and Serial Homology! #And extreme specialization! Two Great Branches of Bilaterian Tree ! Protostomes " Lophotrochozoa # E.g. Annelids " Ecdysozoa # E.g. Arthropods ! Deuterostomes " E.g. Chordates Chordates Its a long way from Amphioxus Chordate Characteristics ! Notochord Unity of Plan "Structural support ! Dorsal Hollow nerve cord 33.5b "Elsewhere ventral ! Pharyngeal slits "Feeding, then breathing ! Muscular Tail "Propulsion Chordates and Activity Level ! From ancestors with a relatively low metabolic rate, chordates evolve a highly active lifestyle!! ! Parallels among the Protostomes Vertebrate Origins Urochordata Cephalochordata Vertebrata = Ascidian = Amphioxus ? Amphioxus Our baseline for vertebrates ! Like vertebrates "Segmented "Can be fast ! But, lack "Well-developed brain "Heart "Gills/lungs ! And is small Vertebrate Origins ! Great sense organs "Eyes, nose, hearing "(Protostomes too!) Vertebrate Origins ! Great sense organs "Eyes, nose, hearing "(Protostomes too!) ! Jointed skeleton "(Arthropods too!) "e.g.Vertebral column Vertebrate Origins ! Great sense organs "Eyes, nose, hearing "(Protostomes too!) ! Jointed skeleton "Vertebral column "(Arthropods too!) ! Extreme cephalization "(Some protostomes, too!) Vertebrate Relationships Gnathostomata Tetrapoda "Agnatha" "Fishes" Amphibians Amniotes Amniotic egg Jointed limbs Jaws Vertebrate Relationships See 34.14 ! Agnatha "No Jaws ! Gnathostomata "Jaws #Evolve from gill arches #More effective feeding #Supports higher metabolism Sharks and bony fishes ! Extremely successful in water "Most vertebrates are bony fishes "Wide range of habitats "No major invasions of land Tetrapoda ! Amphibians, Reptiles, Birds, and Mammals ! Very successful on land ! Jointed appendages "More effective movement "(Arthropods too!) ! Amphibians still rely on water for reproduction "The bryophytes of the vertebrate world Amniotes ! Much more successful on land than amphibians "Reptiles "Birds "Mammals ! Have dry scaly skin to reduce water loss (remember the plant cuticle?) Amniotes ! Much more successful on land than amphibians "Reptiles "Birds "Mammals ! Amniotic egg Amniotes ! Amniotic egg "Protection of embryo from environment Fig. 34.16 #Amnion "Storage of wastes #Allantois "Gas exchange #Chorion Reptiles ! Paraphyletic "Some closer to birds (e.g. croc) or mammals than to other reptiles ! Dominated land for a very long time "Overshadowed mammals for 140 million years! Birds and Mammals Independently evolved a high metabolic rate! ! High body temperature "Insulation - feathers or fur ! Very efficient locomotion ! Very efficient respiration ! Four chamber heart "Complete separation of high/low oxygen blood Birds and Mammals Independently evolved a high metabolic rate! Lizards Turtles Snakes Crocodiles Birds Mammals 4-chamber heart Warm blood ! respiration ! circulation Amniotic egg ! locomotion Birds ! Flight "Feathers ! Archaeopteryx intermediate in many ways "Teeth "Claws "Long, bony tail Mammals ! Arose about 220 mya ! Primitively, laid eggs "Two species still do! #Platypus, echidna ! Derived similarities include "Hair "Lactation "Three-bone middle ear Summary ! Sponges: No true tissues ! Bilateria: Bilateral symmetry, cephalization ! Protostomes vs. Deuterostomes " Trend towards high energy lifestyle ! Chordate characteristics "Notochord, Dorsal hollow nerve cord, Pharyngeal slits, tail ! Gnathostomes have jaws "More efficient feeding Summary - continued ! Tetrapods have jointed limbs "Better locomotion on land ! Amniotes have an amniotic egg "More resistant to drying ! Birds and mammals have independently evolved many features related to a very high metabolic rate "Effective respiration, circulation, locomotion, high body temperature, insulation.
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