biology lecture 15

biology lecture 15 - Lecture 15 Arthropods II,...

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1 Lecture 15 Arthropods II, Metamorphosis, Hormones Oct. 25, 2011 Hormones = chemical messenger substance produced by endocrine system In termites, differentiation of castes is induced by hormones that are released in response to environmental and pheromone cues The most diverse group of arthropods are… 67% 1. The spiders 16% 14% 2. The crustaceans 3. The insects 4. 2 & 3 are tied for being the most T he s p i der The crustacean. .. The in sec t 2 & 3 ar e tied. 3% diverse
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2 Recall: Arthropods are the most diverse eukaryotic group Protozoa, 40 000 Fungi, 70 000 Algae, 40,000 , 3% 965 000 40,000 , 3% 70,000 , 4% Plants, 270,000 , 17% Worms, 25,000 , 2% 965,000 , 62% Vertebrates , 57,600 , 4% Molluscs, 70,000 , 5% Beetles, 340,000 , 35% Crustacea ns, 40,000 , 4% Spiders, 75,000 , 8% Other Insects (e.g. flies, grasshoppers, damselflies) 510,000 , 53% Which of the following statements is NOT true 41% 1. Only cardiac and skeletal 31% 14% 14% muscles contain actin and myosin 2. Some cardiac muscles are capable of generating their own impulses 3. Skeletal muscles are O nly c ar dia c a ... Some cardiac m. .. S ke l et a l m u sc l.. . Cardiac muscle. Skeletal muscles are primarily under voluntary control 4. Cardiac muscle only have a single nucleus per cell
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3 Arthropod Diversity 4 major groups with phylogeny currently in revision • Myriapods (e.g. millipedes, centipedes) • Chelicerates (e.g. spiders, mites & scorpions) • Crustaceans – Dominant in marine enviro • Hexapods (includes insects) – Dominant in terrestrial enviro Myriapods •2 r e g i o n s –Head – Trunk “countless feet” • Centipedes (Chilopoda) – 1 pair of app. per segment – Carnivores – ~3000 sp. • Millipedes (Diplopoda) • Millipedes (Diplopoda) – 2 pairs of app. per segment – detritivores, herbivores – ~11,000 sp.
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4 Chelicerates • horseshoe crabs • pycnogonids (sea spiders) arachnids • arachnids – spiders, mites, scorpions • no jaws (mandibles) • 2 body regions: • cephalothorax – appendages wolf spider • abdomen – no appendages • Pairs of appendages: •# 1 ( chelicerae ) – fangs 2 ( pedipalps ) – copulatory organs, pincers • # 3, 4, 5, 6 – walking legs (4 pairs of walking legs) Crustaceans • crabs, daphnia, barnacles, shrimp, crayfish, isopods… • dominant marine arthropod, but also in freshwater & terrestrial environments • head + thorax (cephalothorax) + abdomen • appendages off each segment • compose “zooplankton” Daphnia
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5 Hexapods = Insects + other groups • Abundant in fw + terrestrial environment, but few marine • 3 body regions: –head : • antennae, mouthparts (e.g. mandibles) –tho rax • 3 pairs of walking legs •may have wings stalk-eyed flies – abdomen
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biology lecture 15 - Lecture 15 Arthropods II,...

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