LIFE 103 1st Edition Lecture 25 Outline of Last Lecture II. Table Continued III. Big 9 focus IV. LophotrochozoaI. PlatyhelminthesII. Mollusca III. Annelida Outline of Current Lecture V. EcdysozoaVI. NematodaVII. ArthropodaVIII. Characteristics of arthropodsIX. Arthropod diversityX. ChelicerataXI. Crustacea XII. Insecta XIII. Size of insectsCurrent LectureI. Clade: common ancestor and all of its descendantsII. Revisiting the last clicker question: invertebrates are NOT a clade Animal taxa: invertebrates III I. EcdysozoaI. LoriciferaII. PripulaIII. TardigradaIV. OnychophoraV. ArthropodaVI. NematodaVII. Defined by molecular evidenceVIII. An external covering (cuticle or exoskeleton)IX. Molted with growth (ecdysis)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.X. Most diverse animal group by far XI. Two big groups are nematodes and arthropodsNematoda-roundworms (15,000 species or up to 1 million)I. Half parasitic, half free-livingII. MotileIII. Nearly all habitats and all elevationsIV. Important in decomposition and nutrient cycling Arthropoda-arthropods (many millions!)I. Every feeding style imaginableII. MotileIII. Marine, freshwater, terrestrial IV. Most successful of all animal phyla V. Five major groupsI. Myriapods- first land animals, centipedes and millipedesII. Trilobites-completely extinct group III. Chelicerates-spiders, mites, scorpions, etc. IV. Crustaceans- crabs, lobsters, etc. V. Insects-moths, butterflies,etc.VI. All have segmentationVII. We’re just focusing on the last three Characteristics of Arthropoda: I. “Arthro” = jointII. “Pod” = footI. Segmented body III. Paired limbs on segmentsIV. Hard exoskeleton (chitin) V. Jointed appendagesI. Helps them move around more easily VI. Open circulatory system (hemolymph circulates through hemocoel) I. Humans have a closed circulatory systemhemolymph carries oxygen binding molecules, like hemoglobin, but it moves into the body cavity VII. Insects are the most diverse group, especially beetles I. “An inordinate fondness for beetles” –J.B.S. Haldane Arthropod diversityI. Hexapoda (most common: weevils) = 89%II. Crustacea (most common: copapods) = 4%III. Myriapoda = 1%IV. Cheliceriformes (most common: mites) = 6%V. Other = 7% Chelicerata – spiders, mites, scorpions, etc.I. Chilcerae (feeding appendages, often venomous) II. CephalothoraxIII. AbdomenIV. 4 pairs of walking legsV. Pedipalps- modified pair of legs used to get food and transfer sperm Crustacea – crabs, shrimp, copepods, amphipods, barnacles, etc. I. Many pairs of walking legsII. Antennae (2 pairs) III. Cephalon, thorax, abdomen (3 big body segments of them) IV. Copepods may be the most numerous of animals on Earth V. Barnacles have to get creative: hermaphroditism, spermcasting, very large organs Insecta – insects (beetles, butterflies, ants, bees, cockroaches, flies, etc.) I. Abdomen, thorax, headII. Antennae (only one pair)III. Wings (true flight) some of the only animals IV. 3 pairs of walking legsV. Metamorphosis larval stage that does not resemble the adult stage, undergo this in life cycles, egg becomes larvae, then pupil, then adult (complete metamorphosis) a. Incomplete = grasshoppers, look like adults at start but get bigger Clicker question: The phylum Arthropoda is made up of these living groups: insects, chelicerates, crustaceans, and myriapods Why aren’t insects larger? I. Still pretty small II. Heaviest modern insect: giant weta III. Largest modern insect: stick insectIV. Largest known insect was a
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