Week 1 - Intro to body plans and phylogeny Flashcards
What are the bilaterian animals?
Protostomes - molluscs, annelids, arthropods.
Deuterostomes - echinoderms, chordates
What is the collective scientific name given to animals that are capable of moulting?
Ecdysozoa
Why is the colonial theory of animal origins favoured by zoologists?
That the first animals display their evolution from the flagellated protist that survived in clusters
What is the Cambrian Explosion?
A period of rapid evolution that occurred around 540 million years ago, when most major animal groups first appeared in the fossil record.
What factors might have triggered the origin of mineralized skeletons?
- Environmental Changes
- Increased Oxygen Levels
- Predation Pressure
- Competition for Resources
- Evolution of New Metabolic Pathways
What are the major differences between Pre-Cambrian and Cambrian assemblages?
Pre-Cambrian -
- 4.6 billion to 541 million years ago.
- Multicellular organisms
Cambrian -
- 541 to 485 million years ago
- Complex multicellular organisms
What is the Cambrian Substrate Revolution
A sudden diversification of animal burrowing during the early Cambrian period.
Why is the Cambrian Explosion evolutionarily significant?
The appearance of many of the major phyla
Why is the Cambrian Explosion ecologically significant?
It set the stage for the evolution of most of life today
What are the three major domains of life?
Bacteria, Archaea, Eukarya
What are two unique characteristics of metazoans?
Blastula formation - A unique stage in the embryonic development of metazoans.
Integrated nervous and muscular systems- These systems give metazoans unprecedented mobility and responsiveness to environmental circumstances
What is enterocoely?
The stage of development in which the coelom forms.
What are two functional roles of the body cavity?
Contains and protects internal organs
What is the pseudocoel?
A fluid filled body cavity
What is a zygote?
A fertilised egg cell that contains genetic information.
