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Questions and Answers
What characteristic defines animals as ingestive heterotrophs?
What characteristic defines animals as ingestive heterotrophs?
During which era did the Cambrian Explosion occur?
During which era did the Cambrian Explosion occur?
Which of the following describes coelomates?
Which of the following describes coelomates?
What significant development led to the emergence of complex multicellular eukaryotes?
What significant development led to the emergence of complex multicellular eukaryotes?
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Which body plan symmetry is characterized by having a defined right and left side?
Which body plan symmetry is characterized by having a defined right and left side?
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What is the main feature of pseudocoelomates?
What is the main feature of pseudocoelomates?
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In what era do large non-flying dinosaurs go extinct?
In what era do large non-flying dinosaurs go extinct?
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What is the primary role of Hox genes during development in animals?
What is the primary role of Hox genes during development in animals?
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What era marks the origin of the first complex multicellular eukaryotes in the fossil record?
What era marks the origin of the first complex multicellular eukaryotes in the fossil record?
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During which era did land vertebrates evolve?
During which era did land vertebrates evolve?
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What type of body cavity does acoelomates possess?
What type of body cavity does acoelomates possess?
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Which of the following is a characteristic feature of the Cambrian Explosion?
Which of the following is a characteristic feature of the Cambrian Explosion?
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Which body plan symmetry is characterized by no specific left or right side, often seen in organisms like jellyfish?
Which body plan symmetry is characterized by no specific left or right side, often seen in organisms like jellyfish?
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What significant evolutionary event occurred in the Mesozoic Era?
What significant evolutionary event occurred in the Mesozoic Era?
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What primary role do Hox genes play during animal development?
What primary role do Hox genes play during animal development?
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Which era followed the mass extinctions that eliminated large non-flying dinosaurs?
Which era followed the mass extinctions that eliminated large non-flying dinosaurs?
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Study Notes
Introduction to Animal Diversity
- Animals are ingestive heterotrophs
- Animals are multicellular
- Animals have tissue development
- Animals have developmental stages regulated by Hox genes
Developmental Stages in Animal Embryos
- Zygote undergoes cleavage
- Cleavage results in eight-cell stage
- Further cleavage forms blastula (hollow ball)
- Blastocoel forms
- Gastrulation occurs forming a gastrula
- Gastrulation establishes three germ layers
- Three germ layers are: ectoderm, mesoderm & endoderm
- Archenteron, forms the digestive tube
- Blastopore, opening in the archenteron may develop into mouth or anus
Animal Origins
- Choanoflagellates are closely related to animals
- Similar cells (choanocytes) found in sponges & choanoflagellates
- DNA sequence data supports close relationship between choanoflagellates & animals
- Genes for signaling and adhesion proteins found in choanoflagellates and animals
Embryonic Germ Layers
- Endoderm: gut, liver, lungs
- Mesoderm: skeleton, muscle, kidney, heart, blood
- Ectoderm: skin, nervous system
Geologic History of Animals
- Proterozoic Era (pre-Cambrian): 2.5 bya - 542 mya
- Eukaryotes arose 2.5 bya
- Common ancestor to multicellular organisms 1.5 bya
- First complex multicellular eukaryotes (animals) appear in fossil record 565 mya (Ediacaran biota)
- Paleozoic Era: 542-251 mya
- Cambrian explosion: 535-525 mya
- Land invertebrates evolved 460 mya
- Land vertebrates evolved 360 mya
- Mesozoic Era: 251-65.5 mya
- Land animals evolved into new niches
- Evolution of wings
- Flowering plants evolved in Cretaceous (late Mesozoic)
- Cenozoic Era: 65.5 mya - present
- Mass extinctions just before Cenozoic: large non-flying dinosaurs and marine reptiles lost
- Origin of primates
Body Plans - Symmetry
- Radial symmetry
- Bilateral symmetry
Body Plans - Tissues
- Diploblasty: two tissue layers (ectoderm and endoderm)
- Jelly-like material between ectoderm & endoderm
- Triploblasty: three tissue layers (ectoderm, mesoderm, and endoderm)
- Mesoderm layer between ectoderm & endoderm
- Internal organs develop from mesoderm
Body Plans - Body Cavities
- Coelomate: body cavity (coelom) lined by mesoderm
- Pseudocoelomate: body cavity (pseudocoelom) not completely lined by mesoderm
- Acoelomate: no body cavity
Protostomes vs. Deuterostomes
- Protostomes: Spiral and determinate cleavage, coelom formation by splitting, mouth develops from blastopore
- Deuterostomes: radial and indeterminate cleavage, coelom formation by outpocketing, anus develops from blastopore
Phylogeny of Animals
- Phylogenetic tree showing evolutionary relationships among animals
- Ancestral protists, eventually evolving into different groups of animals (e.g. sponges, cnidarians, bilaterians)
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Description
Explore the fascinating world of animal diversity and the stages of development in embryos. This quiz covers topics from multicellularity and tissue development to the specific embryonic stages and germ layers. Test your understanding of the origins of animals and their evolutionary relationships.
