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The flashcards below were created by user
kamrunsreno
on FreezingBlue Flashcards.
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Animal Characteristics
- Defined by being:
- multicellular
- Eukaryotic
- Heterotrophic
- Diplontic life cycle
- Diploid multicellular body, haploid gametes, produced by meiosis
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Animal Reproduction and Development
- Diploid body creates gametes (meiosis)
- Haploid gametes create diploid zygote
- n+n-->2n (fertilization)
- Zygote undergoes cell division
- Creates blastula (often a hollow ball of cells)
- Gastrulation folds embryo inward
- Leads to the formation of gastrula
- Infolding creates the blastopore
- Grastula has:
- Outer ectoderm
- inner ectoderm
- Inner pouch called the archenteron
- Archenteron will become the digestive tract
- Gastrulation does not occur in sponges
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Animal Body Plans.
Animals can be categorized by many features of their body structures
- Symmetry
- Tissues
- Body Cavity
- Developmental mode
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Symmetry
- assymetry
- no symmetry in body plan
- radial symmetry
- multiple planes create a mirror immage
- bilateral symmetry
- Only one plane creates a mirror image
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Tissue Origin
- Tissues are specialized cells grouped together with a unified function
- Tissues arise from germ layers of gastrula
- Ectoderm-->outer covering of animal
- Endoderm--> digestive tract
- Mesoderm --> muscles, internal organs
- Other organs can arise from ectodern/endoderm
- Some animals lack tissues (sponges)
- Diploblastic animals have 2 germ layers (ectoderm and endoderm--ex. Jellies)
- Triploblastic animals have 3 germ layers
- Ectoderm, endoderm, and mesoderm
- Ex. all bilaterally symmetrical animals
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Body Cavities
- Fluid or air-filled space
- Seperates digestive tract from outer body wall
- Found in most triploblastic animals
- Allows organs to be suspended independently
- Body cavity also called coelom
- A true coelom develops from mesoderm
- True coelom completely lined with epithelium
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Developmental Modes
- Two developmental modes:
- Protostome development
- Deuterostome development
- Defined by differences in:
- Fate of blastopore
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