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Reproduction Systematics and Taxonomy. BIOL240.002 Zoology 22 September 2014. Oviparity. Eggs laid by ♀ External fertilizers Many internal fertilizers Planktonic eggs: Eggs drift about in water Ex : Most cnidarians Ex : Most echinoderms Egg masses: Ex : Frogs.
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ReproductionSystematics and Taxonomy BIOL240.002 Zoology 22 September 2014
Oviparity • Eggs laid by ♀ • External fertilizers • Many internal fertilizers • Planktonic eggs: Eggs drift about in water • Ex: Most cnidarians • Ex: Most echinoderms • Egg masses: • Ex: Frogs Fig. 7.10 p. 139 Fig. 17.16 p. 363
Oviparity • Protective/Nutritive deposition of eggs: • Ex: Ichneumon wasps • Ex: Some sharks’ “mermaid’s purses” • Ex: Turtle nests Fig. 13.46 p. 274
Oviparity • Brooding: one or both parents tending to eggs in/on body or in nest • Ex: Bryozoans • Ex: Some salamanders and caecilians • Ex: Crocodilians • Ex: Birds Fig. 9.4 p. 179 Fig. 17.6 p. 357 Fig. 17.4 p. 357
Viviparity • Live bearing of young • Fewer young/Higher survival • Aplacentalviviparity • aka Lecithotrophy • aka Ovoviviparity • Ex: Some sharks • Ex: Some snakes and lizards • Placentalviviparity • aka Matrotrophy • Ex: Some sharks • Ex: Velvet worms • Ex: Most caecilians • Ex: A few snakes • Ex: Almost all mammals
Seahorse Male “Pregnancy” • A father seahorse “giving birth” • Female deposits ova in his brood pouch • Egg brooding that resembles pregnancy
Direct Development • Juveniles resemble adults • Ex: Velvet worms • Ex: Reptiles • Common in terrestrial animals • Major exception: Winged insects
Indirect Development • Young hatch or are born as larvae which will undergo metamorphosis • Ancestral condition in Animalia • Important for dispersal in animals whose adults are sessile, parasitic, or otherwise have limited mobility • Some animals pass through multiple larval stages • Ex: Three in mussels (trocophore, veliger, glochidium) • Ex: Four in liver fluke (miracidium, sporocyst, redia, cercaria) Fig. 8.10 p. 162 Figs. 10.6, 10. 7, 10.30 pp. 191-205
Development in the Hexapoda • Primitive wingless hexapods: Direct • Ex: Silverfish • Incomplete metamorphosis • Nymph or naiad undergoes metamorphosis but looks much like adult • Ex: Mayfly • Ex: Stonefly • Complete metamorphosis • Larva looks little like adult it will become • Ex: Maggot Fly • Ex: Grub Beetle • Ex: Caterpillar Butterfly Fig. 13.60 p. 282 Fig. 13.61 p. 282 Fig. 13.47 p. 274
Early Biological Taxonomy • Modern system originated in late 1500s • Latin: Universal language of science • Names were initially polynomials • Descriptive of the species they named • Ex: Apispubescensthoracesubgriseoabdominefuscopedibusposticusglabrisutrinquemargineciliatis • (European honeybee) • Some early naturalists experimented with shorter names
Karl von Linne • aka CarolusLinneaus • Swedish botanist (1707–1778) • 1735: 1st ed. of SystemaNaturae • Named and described plants and animals • Polynomials • 1758: 10th ed. • Binomials • Ex: Apismellifera • Named and described 7700 spp. of plants and 4400 spp.of animals in his lifetime Fig. 4.1 p. 77
The Linnean Hierarchy • Also used in the 10th ed. of SystemaNaturae • KCOGS • Soon, P and F added • KPCOFGS
Obligate and NonobligateLevels of Taxonomy • Obligate Levels: KPCOFGS • Domain, too, since 1990 • Non-obligate levels • Inserted between the obligate levels • Used in taxa that have many spp., to sort out their diversity • Ex: Order Coleoptera—400,000 spp. • Suborder Adephaga—9 families • ground and tiger beetles, whirligigs, etc. • Suborder Archestomata—5 families • reticulated and telephone-pole beetles, etc. • Suborder Myxophaga—4 families • skiff beetles, etc. • Suborder Polyphaga—148 families • contains a total of 5 infraorders and 16 superfamilies Fig. 4.9 p. 90
The Linnean Taxonomic Hierarchy Table 4.1 p. 78
Describing New Species • Lately, ~6200 new species names and descriptions are published annually (all taxa) • Type specimen in a museum • Detailed description along with name in print • Avg. taxonomist: ~25 spp. in a career • 1,244,360 spp. of organisms have been described (2011 compilation) • 8,118 protozoans (2014 Catalogue of Life: 12,695) • 953,434 animals (2014: 1,088,043) • 215,644 plants (2014: 342,914) • On average, taxonomic specialists estimate 18% of species names are invalid synonyms of previously-described species