A succession of mitotic cell divisions without cell growth between divisions
Cleavage leads to the formation of a multicellular stage called a:
Blastula
Following the blastula stage is the process of:
Gastrulation
What happens during gastrulation?
The layers of embryonic tissue that will develop into adult body parts are produced
What stage is after gastrulation?
gastrula
What is a larva?
A sexually immature form of an animal that is morphologically distinct from the adult, usually eats different food, and may even have a different habitat than the adult
Animal larvae eventually undergo metamorphosis, which is what?
A developmental transformation that turns the animal into a juvenile that resembles the adult but is not yet sexually mature
The first generally accepted macroscopic fossils of animals date back to when?
565 to 550 million years ago
The earliest animal fossils are members of soft bodied multicellular eukaryotes known collectively as:
Ediacaran biota
When was the Neoproterozoic Era?
1 Billion-542 Million Years ago
When was the Paleozoic Era?
542-251 Million Years Ago
A wave of animal diversification that occurred 535-525 Million years ago is known as:
The Cambrian Explosion
Vertebrates made the transition to land around how many years ago?
365 Million Years ago
When was the Mesozoic Era?
251-65.5 Million Years Ago
List the order of the Eras:
Neoproterozoic Era
Paleozoic Era
Mesozoic Era
Cenozoic Era
(NPMC)
In what era did the dinosaurs and some birds emerge from?
Mesozoic Era
What is a body plan?
A particular set of morphological and developmental traits integrated into a functional whole-the living animal
What side is the dorsal side?
The top side
What side is the ventral side?
The Bottom Side
Anterior:
Front
Posterior:
Back
Define Cephalization:
An evolutionary trend towards the concentration of sensory equipment at the anterior end of the body
What is the germ layer that gives rise to the outer covering of the animal and in some phyla, the CNS?
Ectoderm
What germ layer lines the pouch that forms during gastrulation?
Endoderm
Animals that only have Endoderm and Ectoderm germ layers are said to be:
Diploblastic
What are some examples of Diploblasts?
Cnidarians (Jellies and Corals)
Comb Jellies
All bilaterally symmetrical animals have a third germ layer called:
Mesoderm
The mesoderm fills much of the space between what germ layers?
Ectoderm and Endoderm
Animals with bilateral symmetry are said to be:
Triploblastic
Triploblastic means:
Having 3 Germ layers
Which germ layer forms muscles in triploblasts?
Mesoderm
A fluid or air filled space located between the digestive tract and the outer body wall is known as what?
Coelom
Animals with true coelom are known as:
Coelomates
Some triploblastic animals have a body cavity that is formed from the mesoderm and endoderm. Such a cavity is known as:
A pseudocoelom
Triploblastic animals that lack body cavities are known as:
acoelomates
Define spiral cleavage:
The planes of cell division are diagonal to the vertical axis
Define determinate cleavage:
A type of embryonic development in protostomes that rigidly casts the development fate of each embryonic cell very early
What are the two kinds of development?
Protostome Development
Deuterostome Development
Deuterostome Development is predominantly characterized by what?
Radial Cleavage
Define interdeterminate cleavage:
Each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo. A characteristic of most animals with Deuterostome Development
What type of cleavage makes identical twins in humans possible?
Interdeterminate cleavage
What is an archenteron?
The endoderm lined cavity formed during gastrulation that develops into the digestive tract of an animal
An archenteron forms during which kind of development?
Protostome Development
What is a blastopore?
The opening of the archenteron that typically develops into the anus in Deutorostomes and the Mouth in Protostomes
What are the 5 significant aspects of animal phylogeny?
1. All animals share a common ancestor
2. Sponges are basal animals
3. Eumetazoa is a clade of animals with true tissues
4. Most animal phyla belong to the clade Bilateria
5. Chordates and some other phyla belong to the clade Deuterostomia
All animals except for sponges and a few others belong to a clade of:
Eumetazoans
What are the characteristics of bilaterians?
Bilateral Symmetry
The Presence of 3 Germ Layers
The cambrian explosion was primarily a rapid diversification of:
Bilaterians
What is the defining feature of Ecdysozoans?
That the animals secrete external skeletons
What is the process of shedding an external skeleton called?
Ecdysis
What is the defining feature of Lophophores?
The presence of a crown ciliated structure called a lophophore that functions in feeding
Individuals in other phyla of the clade lophotrochozoan, including molluscs and annelids, go through a distinctive developmental stage called: