Study Cards Flashcards
Endoderm (inner layer)
Lung cells (alveolar), thyroid cells, digestive cells
Mesoderm (middle layer)
Cardiac muscle, skeletal muscle, smooth muscle, tubule cells, red blood cells
Ectoderm (outer layer)
Skin cells, pigment cells, neurons (nerves)
Acoelomates
Lack a body cavity with organs
Coelomates
Have a body cavity with organs
Chanoflagellates
Free-living protists, unicellular and colonial protists
Choanocytes
Cells in sponges
Ediacaran Period
630-540 million years ago; Fossils mostly from Southern Australia
Cambrian Period
540-490 million years ago; Fossils mostly from Southern Australia
Cambrian Explosion
540-505 million years ago; Fossils of mostly modern animal phyla appeared during this time; Led to the emergence of Echinoderms, Arthropods, Chordates, Molluses, etc…
Filter Feeders
Capture particles suspended in the water that passes through its body
Characteristics of sponges
- Lack nerve muscles, internal organs (no true tissues)
- collagen (protein) holds individual cells together
- built around a central cavity (not a gut)
- mostly marine
Characteristics of Invertebrates
- lack a cranium (skull that encloses the brain)
- lack defined vertebral column or spine
- live in terrestrial and aquatic environmnets
- many have a hard outer skeleton that protects the body
What does it take to be an animal?
- multicellular eukaryotes
- heterotrophic organisms
- no cell walls/ chloroplasts
- cells organized into tissues (nervous/muscle - allows them to move)
- MOSTLY reproduce sexually
- diploid stage (2n) dominates life cycle
- embryos undergo gastrulation
Hox genes
Controls whether a segment of the embryo will form part of the head, thorax, or abdomen
Radial symmetry
Organisms without a central nervous system
Bilateral symmetry
Organisms with a central nervous system
Cephalization
The concentration of nervous tissue at one end of the body (led to development of the brain/head)
What are the two factors for animal grouping?
Body symmetry and developmental pathway
What traits distinguish animals from the other eukaryotic kingdoms?
