BIOL 225 (invertebrates:vertebrates) Day 2 PDF

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Emma Despland...

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BIOL 225 – Day 2 (Invertebrates/Vertebrates) Most animals are invertebrates Remember names in titles in bold Lophotrochozoan: Flatworms – remember (Not Latin name) flukes, planarians, and tapeworms Annelids – Segmented (earth worm, leech, tubeworm) Rotifers Molluscs Invertebrates – animals lacking a backbone (95% known animals) Gastrovascular Cavity - primary organ of digestion and circulation in two major animal phyla: the Cnidaria (including jellyfish and corals) and Platyhelminthes (flatworms). Cuticle The cuticle is shed or molted through a process called ecdysis Largest Phyla = nematodes & arthropods Homologous – Evolutionary related/ derived from structurally Ecdysozoans: Nematodes – Roundworms, C. elegans Arthropods – (INSECTS, crustations (lobster, crail,etc.) lice, ticks, scorpions, ladybugs, spiders. Quizzes: -

Evolutionary origin is the specialization of body segments.

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In insects, adults have wings, but nymphs do not. So, when you see a miniature, wingless grasshopper with no wing, it is a nymph.

Echinoderms & Chordates are DEUTEROSTOMES

Echinoderms - (Sea Stars, Sea Urchins, Sand dollars, Sea Cucumbers, Brittle Stars) They have 5-way-symmetry Only larvae are bilateral, but adults are 5 way symmetrical. Chordates – (phylum Chordata) are bilaterian animals that belong to the clade of animals known as Deuterostomia. Chordates comprise all vertebrates and two groups of invertebrates. Basic traits: 1 – Notochord 2 – Dorsal, hollow nerve cord (provides support for the body) 3 – Pharyngeal Slits or clefts 4 – Muscular, post-anal tail

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NOTOCHORD: The notochord is a longitudinal, flexible rod between the digestive tube and nerve cord It provides skeletal support throughout most of the length of a chordate In most vertebrates, a more complex, jointed skeleton develops, and the adult retains only remnants of embryonic notochord Dorsal, Hollow Nerve Cord:

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The nerve cord of chordate embryo develops from a plate of ectoderm that rolls into tube dorsal to notochord The nerve cord develops into the central nervous system: the brain and spinal cord Pharyngeal Slits or Clefts: In most chordates, grooves in the pharynx called pharyngeal clefts develop into slits that open to the outside of the body Functions of pharyngeal slits + Suspension-feeding structures in many invertebrate chordates + Gas exchange in vertebrates (except vertebrates with limbs, the tetrapods) + Develop into parts of the ear, head, and neck in tetrapods

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Muscular, Post-Anal Tail Chordates have a tail posterior to the anus In many species, the tail is greatly reduced during embryonic development The tail contains skeletal elements and muscles It provides propelling force in many aquatic species

Vertebrates are chordates that have a backbone. - They have 2 or more sets of Hox genes Enclosing a spinal cord An elaborate skull

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Hagfishes & Lampreys Jawless vertebrates. (only two lineages that we know of)

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Gnathostomes (“JAW MOUTH”) Vertebrates that have jaws (sharks, ray-finned fish, lobe-finned fish, amphibians, reptiles , and mammals)

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Aquatic Gnathostomes system of tactile sense organs that serves to detect movements and pressure changes in the water. *(sensitive to vibrations)

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Chondrichthyans (Sharks, Rays, Skates) have a skeleton composed primarily of cartilage Osteichthyes (Bony fish & tetrapods)

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Bony Endoskeleton Aquatic Osteichthyans are the vertebrates we call fish Tetrapods...