Podcast
Questions and Answers
What characteristic defines animals as ingestive heterotrophs?
What characteristic defines animals as ingestive heterotrophs?
- They rely on decomposing organic matter for sustenance.
- They ingest food and derive energy from it. (correct)
- They absorb nutrients directly from their environment.
- They produce their own food through photosynthesis.
During which era did the Cambrian Explosion occur?
During which era did the Cambrian Explosion occur?
- Mesozoic Era
- Proterozoic Era
- Cenozoic Era
- Paleozoic Era (correct)
Which of the following describes coelomates?
Which of the following describes coelomates?
- They possess a body cavity completely lined with mesoderm. (correct)
- They have a body cavity partially lined with mesoderm.
- They have two separate body cavities.
- They lack a true body cavity.
What significant development led to the emergence of complex multicellular eukaryotes?
What significant development led to the emergence of complex multicellular eukaryotes?
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?
What is the main feature of pseudocoelomates?
What is the main feature of pseudocoelomates?
In what era do large non-flying dinosaurs go extinct?
In what era do large non-flying dinosaurs go extinct?
What is the primary role of Hox genes during development in animals?
What is the primary role of Hox genes during development in animals?
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?
During which era did land vertebrates evolve?
During which era did land vertebrates evolve?
What type of body cavity does acoelomates possess?
What type of body cavity does acoelomates possess?
Which of the following is a characteristic feature of the Cambrian Explosion?
Which of the following is a characteristic feature of the Cambrian Explosion?
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?
What significant evolutionary event occurred in the Mesozoic Era?
What significant evolutionary event occurred in the Mesozoic Era?
What primary role do Hox genes play during animal development?
What primary role do Hox genes play during animal development?
Which era followed the mass extinctions that eliminated large non-flying dinosaurs?
Which era followed the mass extinctions that eliminated large non-flying dinosaurs?
Flashcards
Animal Characteristics
Animal Characteristics
Animals are multicellular, ingest food, and have specific developmental stages controlled by genes.
Animal Origins
Animal Origins
The first complex multicellular animals appeared in the fossil record about 565 million years ago during the Proterozoic Era.
Cambrian Explosion
Cambrian Explosion
A significant increase in animal diversity occurred during this period (535-525 my bp).
Animal Symmetry
Animal Symmetry
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Body Tissues
Body Tissues
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Body Cavities
Body Cavities
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Paleozoic Era
Paleozoic Era
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Mesozoic Era
Mesozoic Era
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Ingestive Heterotrophs
Ingestive Heterotrophs
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Multicellular
Multicellular
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Tissue Development
Tissue Development
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Hox Genes
Hox Genes
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Ediacaran Biota
Ediacaran Biota
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Coelom
Coelom
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Pseudocoelom
Pseudocoelom
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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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