Intro to Animals
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What gives rise to tissues and organs?
the embryonic/germ layers
What is Diploblastic?
- have 2 germ layers (ectoderm and endoderm)
- includes cnidarians (jelly fish and anemone) and comb jellies
What is Triploblastic?
- have 3 germ layers (ecto, endo and mesoderm)
- includes: flatworms, arthropods (have an exoskleteton), vertebrates and others
What is a coelem?
- a true body cavity (derived from mesoderm)
- fluid or air filled space
- internal organs are suspended in
What is a pseudocoelom?
body cavity derived from meso and endoderm
What are triploblastic animals with a body cavity called?
What are triplosblastic animals lacking a body cavity called?
What are the two main types of cell development?
Protostome and deuterostome
What is protostome development?
- spiral (cells are not parallel)
- have a determinate cleavage
- fate of cell is determined early
What is deutrostome development?
- Radial (form parallel/perpendicularly)
- indeterminate cleavage
- each cell can complete an embryo (can from identical twins)
What characteristics do the old and new tree agree on?
- Animalia: monophyletic
- All animals share the common ancestor colonial flagellate
- sponges are basal animals
- Eutetazoa is a clade with true tissues
- most animal phyla belong to the clade Bilateria
- chordates belong to the clade Deuterostomia
What characteristics do the old and new tree disagree on?
old: divides bilaterian into the clades deuterostomes and protostomes
New uses three clades: deuterostomia, ecdysozoa and Lophotrochozoa
What are the old and new trees based on?
- old= morphology
- new= molecular evidence
What did the common ancestor of animals resemble?
Characteristics of Choanoflagellata
- Heterotrophic protist
- single flagellum surrounded by collar of microvilli
- fingerlike projections of cell membrane
- similar cell morphology to sponges
What appeared in the Cambrian period?
- complex life, including those with skeletons appeared (most major phyla appeared)
- 535-525 mya
- during Paleozoic era (542-251 mya)
- 251-65.5 mya
- first mammals emerged
- dinosaurs were dominant terrestrial vertebrates
- coral reefs emerged
- plants and insects became more diverse
- 65.5 mya-present
- began with mass extinction of animals
- mammals became dominant
- global cooling
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