Biology Homework Chapter 18: Invertebrates - Arthropods to Chordates
Textbook Assignment: Chapter 18: The Evolution of Invertebrate Diversity, sections 11-16.
- 18.11 Arthropods: bilateral, segmented, jointed appendages, exoskeletons (growth by molting); primary groups are chelicerates, arachnids (spiders), millipedes and centipedes, crustaceans, and insects.
- 18.12 Insects: Diversity among insects requires special attention. Insects have head with antennae and mouth parts, thorax with three pair of legs, abdomen with organs; some have wings. Metamorphosis common, either incomplete (adult form similar to juvenile), or complete (larval, pupae, adult stages do not resemble each other). Includes grasshoppers, damselflies, true bugs, beetles, moths and butterflies, flies and mosquitos, and ants, bees and wasps.
- 18.13 Differences in arthropods have challenged biologists, who proposed the development of new homeotic genes as the source of new body plans. However, experiments with worms and arthropods show no difference in genes, only differences in how certain homeotic genes are expressed.
- 18.14 Echinoderms: juvenile forms have radial symmetry, spiny skin, endoskeletons, water vascular systems; sometimes bilateral as adults; include starfish, brittle stars, sea lilies, sea cucumbers.
- 18.15 Chordates have hollow nerve cords running down their backs (dorsal side), notochords to protect the nerve cord, pharyngeal slits, and a postanal tail; include tunicates and lancelets.
- 18.16 Habitat change and destruction threatens species of invertebrates with extinction. Some of these invertebrates -- such as bees, which pollinate many food crops -- are crucial to their ecological systems.ss
Read the following weblecture before chat: The Evolution of Animal Diversity, focussing on those protostomes that have a coelom.
Take notes on any questions you have, and be prepared to discuss the lecture in chat.
Perform the study activity below:
Explore the Interactive Tree of Life. Starting at the center, work down toward the Eukaryotic (pink) section to one of the species identified on the rim. Play with the displays (Circular, Rectangular, Unrooted). How do different views of the phylogentic tree shape your image of the relationships involved?
Chat Preparation Activities
- Essay question: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer before chat starts for this session.
- Mastery Exercise: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.
- Required: Complete the Mastery Exercise with a score of 85% or better.
- Optional: Test yourself with the textbook multiple choice questions and note any that you miss that still don't make sense. Bring questions to chat!
- Go to the Moodle and take the quiz for this chapter.
Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.
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