What are the ways that animals are recognized?
Basic body plan, # of tissues in embryos, symmetry, presence/absence of a body cavity, early events in embryonic development
What are animals distinguished by?
Multicellularity, ingest food, move under own power at one point in life, no cell wall, muscle + nervous tissue
What has happened to the basic body plan?
Stayed the same
Name the 4 features of the body plan
# of tissue layers found in embryos, type of body symmetry & degree of cephalization, presence/absence of a fluid-filled body cavity, way in which early embyronic development happens
What is a tissue?
Group of similar cells organized into a tightly integrated structural and functional unit
What do sponges have that is kind of like having 1 layer of tissue?
Epithelium - layer of tightly joined cells that covers the surface
Animals whose embryos have 2 types of tissue layers (endoderm and ectoderm)
animals whose embryos have 3 types of tissue layers (endoderm, ectoderm, mesoderm)
What is a germ layer?
One of the 3 basic types of tissue formed during gastrulation that gives rise to all other tissues
What is the ectoderm?
Outermost layer in animal embryos that gives rise to the outer covering (skin) and nervous system
What is the endoderm?
Innermost layer that gives rise to the digestive tract and organs that connect to it (liver, lungs)
What is the mesoderm?
Between ectoderm and endoderm that gives rise to muscles/organs/bones
Where is muscle derived from in diploblasts?
What animals are the only 2 that are not triploblasts?
Cnidarians and Ctenophores
What are cnidarians?
What are ctenophores?
What type of symmetry are sponges?
What is radial symmetry?
Having at least 2 planes of symmetry
What is bilateral symmetry?
Having 1 plane of symmetry and long narrow body
What did bilateral symmetry allow?
What is cephalization?
Evolution of a head region where structures for feeding, sensing, and processing information from the environment are concentrated
What are the only triploblasts that are not bilaterally symmetrical?
Why is cephalization an advantage?
It allows a head up top to sense/process information about the enivornment powered by a long anterior region
What is a coelom?
Internal, fluid-filled body cavity lined with mesoderm
What type of organisms have a coelom?
A triploblast that doesn't have a coelom
A triploblast that has a coelom
A triploblast that has a cavity but it is formed between the endoderm and mesoderm layers in embryo
What is the main purpose of the coelom?
Acting as a hydrostatic skeleton that can allow soft-bodied animals to move w/o limbs
What 3 events differ in early embyronic development of protostomes and deuterostomes?
Cleavage, Gastrulation, Coelom formation
What is cleavage?
Rapid series of mitotic divisions that occurs in the absence of growth
What does cleavage do in protosomes (spiral cleavage)?
The mitotic spindles of dividing cells oreint at an angle to the main axis of the cells, resulting in helical arranged cells
WHat does cleavage do in deuterostomes (radial cleavage)?
The mitotic spindles of dividing cells oreint parallel or perpendicular to the main axes of the cells, resulting in cells that stack directly on top of each other
What happens after cleavage creates a ball of cells?
What is gastrulation
a series of cell movements that forms the 3 embryonic tissue layers.
How does gastrulation start?
when cells move into the center of the embryo , creating a pore that opens to the outside
What does the pore from gastrulation become in protostomes?
What does the pore from gastrulation become in deuterostomes?
How does the coelom of protostomes form?
When cavaties open within each of the two blocks of mesoderm
How does the coelom of deuterostomes form?
When the layers of mesodermal cells bulge out/pinch off to form fluid-filled pockets lined with mesoderm
What is the location of mesoderm inside protostomes in the gut?
2 blocks of mesoderm beside the gut
What is the location of mesodermal cells in the gut of deuterostomes?
Layers of mesodermal cells located on either side of the gut
What is the tube-within-a-tube design?
The basic animal body; inner tube = gut, outer = body wall, mesoderm = muscles/organs
What are the closest living relative to animals?
Most basal animal phylum
The two forms of protostomes
Lophotrochozoa and Ecdysozoa
How lophotrochozoas grow
by extending skeleton size
How Ecdysozoa grow
by shedding external skeleton and expanding their bodies
4 ways of feeding
Suspension feeders, Deposit feeders, fluid feeders, food-mass feeders
3 sources of food
plant/algae, other animals, detritus
How do animal's mouthpats correlate with their method of feeding?
How are suspension feeders and deposit feeders different?
Suspension feeders are diverse, deposit feeders are all similar
2 types of parasites
3 types of predators
Sit and wait, long distance chase, pounce
Function of movement in adults
Finding food, finding mates, escaping from predators
Unjointed limbs are?
Jointed limbs make what possible?
Fast, precise movement
Are all animal appendages homologous?
Yes, the gene Dll was found to be involved in all species
What type of reproduction occurs in animals?
Asexual (bdelloids) and sexual
What type of fertilization can sexual reproduction be?
Internal and external
What is internal fertilization?
Sperm is transferred to female's body
What is external fertilization?
females lay eggs onto a substrate or into open water, males shed sperm on/near eggs
What is it called when the egg is retained on/nourished on the female's body?
What is it called when the egg is retained on the female but is nourished by the yolk of the egg, not the mother?
What is it called when the egg is layed outside of the mother to develop?
What is metamorphosis?
Change from a juvenile to an adult
Holometabolus metamorphosis (complete metamorphosis)
Juvenile form (larva) looks/feeds different from adult and when it has grown enough it secretes a protective pupa and the pupa's body is remodeled
Hemimetabolus metamorphosis (incomplete metamorphosis)
Juvenile is a mini version of the adult that grows into adult
What are the 2 hypothesis for why homometabolus metamorphosis is 10x more common in insects?
Offspring don't compete with adults; specialization in feeding/mating
What are the 2 distinct body types of Cnidarians?
Polyp (sessile and suspension feed) and medusa (motile and feed on crustaceans)