Exam 3a Flashcards
How do we Define animals?
- Multicellular
- heterotrophs (cannot produce food on their own)
- Mobile at some stage of their life
What is Cambian explosion?
Sudden explosion of animals coming into existence.
Why is Cambian explosion a problem to darwin?
Evolution takes time and changes species over time. cambian explosion just happens all at once spontaneously
How do scientists explain the cambian explosion?
Hox Genes.
What are Hox Genes?
They are conductor genes. The are major genes that control developement of other genes. You dont need too many genes to change form.
what is Asymmetrical body plane?
Organisms who dont have a top, bottom,left, or right.
Ex: Bacteria
What is Radially symmetrical body plane?
It has a top and bottom. It has many planes and every plane that goes through the center will break the image into 2 halves that are mirror images.
What is Bilaterally symmetrical body plane?
Only One plane can cut an organism into 2 halves that are mirror images.
What is so important about body planes?
Shape of organisms will affect their lifestyle. Ex: bilaterally symmetrical organisms will have a different lifestyle than a radially symmetrical organism
What is Diploblastic?
Two Embryonic layers
They only have the ectoderm and endoderm.
What is Triploblastic?
Three embryonic layers
They have a ectoderm mesoderm and endoderm
What is a protostome?
Mouth develops first before anus. Came from spiral cleavage
They are Arthropods, mollusks, sgemented worms
What is a deuterostome and example phylum?
Anus develops first before mouth came from radial cleavage
They are choridaters and echinoderms
What is the ectoderm and what does it give rise to?
its the germ layer covering the surface of the embryo, giving rise to the outer covering of the animal
What is the Endoderm and what does it give rise to?
the innermost germ layer that gives rise to teh lining of the digestive tract and organs such as the liver and lungs in vertebrates
What animals are diploblastic?
cnidarians (jelly fish)
What is a mesoderm and what does it give rise to?
a germ layer that fills much of the space between the ectoderm and endoderm. it gives rise to the muscles and most organs between the digestive tract.
What animals are triploblastic?
Flatworms,
arthropods
vertebrates
What is a coelom and give an example animal
A body cavity. its a fluid- or air-filled space located between the digestive tract and the outer body wall.
Earthworms have coelem.
what does a true coelom form?
it forms from tissues derived from mesoderm.
What do you call animals with true coelom?
coelomates
What is a pseudocoelom and give an example animal?
a body cavity that is formed from mesoderm and endo derm. It is NOT a false body cavity.
Roundworms have it
What is acoelomate?
lacking of a body cavity. Planarians have it.
What is a hydroskeleton who has it?
internal body fluids in limited spaced . round worms have it
