Chapter 32 Flashcards
An Overview of Animal Diversity
What is the definition of an animal? 4 points.
-Animals are heterotrophs that are multicellular eukaryotes.
-Usually have Hox genes.
-Do not have cell walls.
-Tissue and muscle are unique and defining characteristics.
What is the cell structure and celuding cleavage, a blastula, blastocoel, gastrulation, and a gastrula?
Animals usually reproduce sexually meaning the diploid stage dominates the animal life cycle. After fertilization occurs, the zygote undergoes cell division known as cleavage. This cleavage leads to formation of multicellular and hollow blastrula. Theblastrula goes through gastrulation formina a gastrula with different layers of tissue.
What are Hox genes and why are they relevant to animal evolution?
Most animals, and only animals, have Hox genes that regulate the development of body form.
The Hox family of genes has been highly conserved, but can produce a wide diversity of animal morphology.
What is larva and metamorphosis?
A larva is sexually immature and morphologically different from the adult. It eventually undergoes metamorphosis to become a juvenile.
What is a choanoflagellate? What was their role in the development of animals?
A group of protists, cited as the closest living relatives to animals. Not extinct, in marine habitats.
What is the role of cadherin in cell to cell adhesion?
Cadherin regulates contact, formation, and stability meaning they’re key in tissue morphogenesis and homeostasis.
What does the term Ediacaran biota refer to?
Early members of the animal fossil record, these dates back 560 Million years.
What organisms are included in the Edicarian Biota?
2 examples are: Mawsonites spriggi and Spriggina floundersi.
What is the age of the oldest anll specialization of animals?
The cambrian explosion is the mark of the earliest fossil appearance of many major groups of animals. Most of the fossils were bilaterans.
What are the 3 germ layers?
Formed in earliest stages of embryonic development.
1. Endoderm (inner layer)
2. Ectoderm (outer layer)
3. Mesoderm (middle layer)
Which germ layers give rise to the major organ systems?
The endoderm gives rise to internal organs.
Describe animal development, incimal fossils?
Most animals reproduce sexually
What is the Cambrian explosion?
The Cambrian explosion (535-525 Million years ago) marks the earliest fossil appearance of major groups of animals.
When did mammals begin to replace dinosaurs as the main large herbivores & predators?
Cenozoic Era (65.5 Million Years Ago to the Present)
What is a body plan?
A set of morphological and developmental traits. Animals can be categorized by presence and type of body plan.
What is an example of a body plan?
Sea Jelly’s have a radially symmetrical body plan.
Crabs however have a Bilateral body plan.
What are the 2 types of body symmetry?
Radial symmetry and Bilateral Symmetry