Bioee 1780 1st Edition Lecture 22Outline of previous lectureI. SpeciationII. Reproductive barriersA) PrezygoticB) PostzygoticIII. Selection and speciationIV. Hybrid zoneA) Secondary hybrid zoneB) Primary hybrid zoneOutline of current lectureI. Announcement II. ReviewIII. AnimalsIV. SpongesV. EumetazoansCurrent lectureI. Announcement*There is a survey you need to complete… you should be getting it this weekII. Review*You are a jelly blubber:1) How many cell layers do you have? When do you begin to differ from bilateria?A: 2 (diploblasts); in the blastula stage2) What type of symmetry do you have? How does it differ from that of a sponge or a fish?A: Radial; sponges are asymmetric and fish have bilateral symmetry*Which of the following do all protostomes exhibit?A) Radial symmetryB) a mouth that derives from the larval blastoporeC) PseudocoelomD) MesodermAnswer: A, B, and DIII. Animals*Eukaryotes>Ophisthokonts>Animals*Most animals are multicellular, arose around 0.8 billion years agoThese 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.*The origin of predation may have been the reason that multicellularity became favored (was this split before or after animals separated from choanoflagellates? Probably before)*The moment of truth: What exactly is an animal? What defines them?-Multicellular? There are also plants and fungi that are-Heterotrophs? Fungi can be-Internal digestion? Tape worms are animals but digest through skin-Movement? Sponges can’t-Answer: we simply have a lot of DNA in commonIV. Sponges*Have specialized cells called choanocytes (synapomorpy) that help them eat*Collar cells also found in basal animals, but not in other protists, plants or fungi*An aggregation of specialized cells*Bodies have pores, atria, osculum, aquatic, mostly marine*Asymmetric, no organs*Spicule skeletons (also a synapomorphy) (made from CaCO3)*A group of sponges is a sleeze*The oldest known sponge is around 600 myo, can be used to better understand the split between sponges and eumetozoansV. Eumetazoans *Symmetrical body plans, true tissues, internal digestion*Diploblast includes -Gastrodermis (endoderm) and epidermis -Ctenophores [box jellies] (ciliates, complete gut, simple life cycle)-Cnidarians (aquatic, usually marine, polyp or medusa, true jellies, incomplete gut, synapomorphy: cnidocytes [explosive stinging or adhesive cells])#Life cycle: fertilized egg finds a happy place, roots and becomes a polyp, then produces medusa stage asexually#Immortal jelly? A type of jelly can revert from a medusa to a polyp, therefore living forever#Hydra: some animals make the float by generating gas, another makes the tenticals, another makes the gonads#Anemones (no medusa stage)#Coral (if it gets too hot, coral bleaching can
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