Week 6 Flashcards
When was the first fossil formed?
Ediacaran- 575mn years
What were the first fossils?
Tribranchidium, Mawsonites, Spriggina
When was the Paleozoic era?
542-251million years ago
What is the Cambrian explosion?
The rapid increase of biodiversity
What caused the Cambrian explosion?
The emergence of predator-prey dynamics
The increase in oxygen levels
Evolution of Hox genes
How has predator prey dynamics increased biodiversity?
The arms race for the development of compound eyes, shells, faster movement has led to a vast difference in species
What is a Hox gene?
These are groups of genes which dictate a certain area of an embryo body region
Why are Hox genes important?
A change in the hox gene means there’s change in the body shape
What was the Mesozoic era
251-65mn years ago, dominated by reptiles and small mammals (dinosaurs here)
When was the transition onto land?
365mya
What is gastrulation?
The folding in of cells, forming two layers the ectoderm and the endoderm
Wat type of cavity do annelids have?
Within the mesoderm
What type of cavity do roundworms have?
Between the mesoderm and the endoderm
What type of cavity do flatworms have?
No cavity- trick question
What is a diploblast
An animal that develops two layers, the ectoderm and the endoderm.
What is a triploblast
An animal that develops three layers, ectoderm, endoderm and mesoderm
How do bilaterians move?
When the longitudianal muscels are relaxed and the circular muscles are contracted the body extends
If the opposite is done then the body contracts
What is a key species of the acoelomate phylum?
Platyhelminthes
