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24 Cards in this Set
- Front
- Back
What broad characterisics define animals?
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Nutritional Mode
Cell Structure Cell Specialization Reproduction and Development |
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Describe the nutritional mode of animals.
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Chemoheterotrophs with internal digestion (ingestive nutrition)
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Describe the differences of animal cells to other organisms.
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Lack cell walls; held together with structural proteins (collagen) or by junctions (tight, gap)
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What specialized cells define animals?
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Nerve and Muscle cells
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When did animals arise?
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800 million-1.2 billion years ago
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What fossil assemblages document the origin and early diversification of animals?
(What are they, what period to they cover, and what types of animals are found in each fossil record?) |
Doushantuo Fossils: Pre-Cambrian, microscopic marine organisms
Ediacaran Fossils: Pre-Cambrian, soft-bodied animals Burgess Shale Fossils: Cambrian, all major phyla |
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What does Gould mean in his quote: "Three billion years of unicellular, followed by five million years of intense creativity and then capped by more than 500 million years of variation on set anatomical themes?"
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Life began as unicellular and remained that way for the majority of life, then experienced a massive diversification in the Cambrian explosion, and became mere modifications to the original designs, since nearly all phyla were in place.
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What is the Cambrian Explosion and when did it occur?
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Cambrian explosion: the sudden appearance of many different phyla in the geologic record; reflects a sudden dramatic increase in diversity of animals; occured 542-521 million years ago.
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Outline the Ecological, Genetic, and Geological Explanations for why the Cambrian Explosion occured when it did. Are these mutually exculsive or could more than one factor be operating at once?
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Ecological
Resource competition; terrestrial niches empty and waiting to be filled Predator-prey relationships; natural selection increases Mass extinctions Genetic Evolution of Hox Genes Mutation Geological Climate Change Atmospheric Change (more available oxygen after plant colonization of land) NOT MUTUALLY EXCLUSIVE |
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What are Hox genes? What is their function with respect to body plan development? How do they contribute to the diversification of animal body plans?
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Hox genes: homeobox containing genes regulating development of body segments
Homeobox: 180 bp DNA sequence in genes regulating development; give rise to transcription factors that bind to other genes responsible for development Location on chromosome determines location of body part |
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Why don't we continue to see the generation of new animal phyla like we did in the Cambrian Explosion?
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Niches filled; hard for another phyla to evolve when there are no niches available.
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What are choanoflagellates and what is their relationship to animals?
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Phylum Choanoflagella; multicellular protists, closest living relative to animals
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Describe the characteristic early developmental pattern of animals. Do all animals follow this pattern?
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Sperm-egg fertilize; zygote
Zygote cleaves/blastulates; blastula Blastula gastrulates; gastrula All animals follow pattern |
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What is meant by body symmetry, radial symmetry, and bilateral symmetry? How does body symmetry correlate with lifestyle?
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Radial symmetry: animal parts radiate from a central axis; mostly sessile or planktonic animals
Bilateral symmetry; animal parts form two chiral halves; mostly free-living animals |
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In what ways do the traditional phylogeny of animals based on morphology/embryology and the molecular phylogeny of the animal kingdom agree and disagree?
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Agreements
1. All animals share a common ancestor 2. Sponges are basal animals 3. Eumetazoa is a clade of animals with true tissue 4. Most animals belong to the clade Bilateria 5. Vertebrates and some other phyla belong to the clade Deuterostomia Disagreement: Relationship among Bilateria Morphological/embryological cladogram two divisons: protostomes and deuterostomes Genetic cladogram three: protostomes, ecdysosomes, locotrophozoans |
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What percentage of animal diversity is composed of invertebrates? What percentage of diversity of life is composed of arthropods
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95% invertebrates
85% arthropods |
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What is the basic body plan of echinoderms, and how do the various classes within this phylum represent variations on this common body plan?
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Five-point body plan
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What are the four uniting characteristics of chordates? Do humans exhibit these four defining characteristics?
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Notochord
Pharyngel Gill Slits/Clefts Dorsal Hollow Nerve Chord Postanal Tail Humand display characteristics while in developmental stages |
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What ancestral chordate feature gave rise to the vertebral column? To jaws?
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Vertebral column arises from notochord; jaws arise from modifications to skeletal rods supporting pharyngeal gill slits
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When did primates evolve? What are examples of the most primitive primates today?
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45 million years ago; Lemurs, Lorises, Pottos, Tarsiers
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What primates constitute the hominoids? How long ago did hominoids arise?
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Constituted by great apes; Giabbons, Orangutans, Gorillas, Chimpanzees, Bonobos, and Humans
Arose about 20-25 million years ago |
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When did hominids split from the great apes?
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7-6 million years ago
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What is the closest LIVING relative of Homo sapiens? What is thought to be the CLOSEST RELATIVE of Homo sapiens?
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Living: Chimpanzees (1.2% difference)
Closest relative: Homo Erectus |
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How can we tell if a fossilized skeleton exhibited bipedlaism?
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Bone structure of pelvis and legs; entrance of vertebral column
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