Lecture 18/19 Flashcards
Collagen?
Structural proteins that hold both cells and bodies
What are two defining characteristics of animals?
Nervous tissue and muscle tissue
Chemoheterotrophic?
Obtain food from chemical, but cannot produce their own carbon based food (consumes other organisms)
Sexual reproduction?
Motile haploid sperm fuses with large non-motile haploid egg to make diploid zygote
Cleavage?
Mitotic cell divisions in diploid zygote
Cleavage leads to?
Formation of hollow blastula (multicellular)
Blastula undergoes?
gastrulation
Gastrulation?
The forming of a gastrula with different embryonic layers.
Protostomes?
Spiral cleavage
Determinate
Determinate?
New cell is destined to form parts in later embryo
Deuterostomes?
Radial cleavage
Indeterminate
Indeterminate?
Early cells not differentiated
Protostomia?
First part of gastrula becomes mouth
Deuterostomia?
First part of gastrula becomes anus
Homeobox?
Highly conserved nucleotide sequence
Radial symmetry?
No front and back, left and right
Bilateral symmetry?
Two sided symmetry
Cephalization?
the development of a head (CNS)
Benefits of bilateral symmetry?
- quicker response to stimuli in environment
- better able to search of food
- better defenses capabilities
Skin and nervous system is derived from?
Ectoderm
Muscles and organs are derived from?
Mesoderm
Gut derived from?
Endoderm
Most triploblastic organisms have?
Fluid filled body cavity
Coelom?
Derived from mesoderm, true body cavity
Coelomates?
Animals that have a true coelom
Pseudocoelomate?
animals that lack a complete mesodermal lining
Acoelomate?
Animals that lack a mesodermal lining entirely
Coelom function?
Cushions internal organs from blows to outside the body
Allows internal organs to grow and shift without deforming outside the body
Common ancestor of animals resembled?
Choanoflagellates (heterotrophic protist)
Colonial hypothesis?
Colony of choanoflagellates may have evolved into an animal with endo and ectodermal layers
Evidence of the hypothesis being correct?
Collar cells in sponges identical to choanoflagellate cells
Similar cells found in jellyfish, flatworms, flatworms
Advantages of multicellularity
- Foraging: improved handling & feeding of prey (size and coordination)
- Defense: less likely to get eaten
- Specialization of tasks (sensory, digestion)
Disadvantages of multiceullarity?
- Most cells don’t reproduce -support few do
* Requires cooperation - opportunities to cheat (ex: cancer cells)
Diffusion?
Random molecule motion from high to low concentration
Evolution of Bulk Flow?
Active transport of oxygen, nutrients, and other molecules in large quantities
