Animal Diversity LAB - Week 3

4 mechanisms by which evolution occur

mutation, genetic drift, natural selection, gene flow

Microevolution

evolutionary change within a species over a shorter period of time

Macroevolution

origin of new species and divisions of taxonomic hierarchy above species level

3 disadvantages to multicellularity

harder to take nutrients, higher energy requirements, harder to distinguish self from others

How is multicellularity characterized?

juvenile/adult life stages, division of labor (apoptosis), determinant growth, adhesion between cells

Clade Porifera is

the sponges

Porifera cellular level of organization

no true tissues or germ layers

Internal skeleton made of…

spicules

mesohyl

gelatinous matrix in sponge

Suspension feeders

system of pores and canals

Asexual reproduction in Porifera

formation of buds/gemmules

Sexual reproduction in Porifera

free-swimming ciliated or flagellated larvae

Sponge body types

ascon, sycon, leucon

Ascon body type

small and simple with tube shaped body

Sycon body type

tube shaped body with thickened, folded walls

Leucon body type

complex, larger in overall body size, thickest walls

osculum

where filtered water is pushed out of

spongocoel

filtered water collects here (central cavity)

choanocytes

specialized cells lining radial canals, trap small food particles with flagella through phagocytosis

pinacocytes

cells making up outer layer of sponge

amoebocyte

mobile cells that carry food to other cells and can turn into any other cell needed (use pseudopodia)

porocyte

elongated, doughnut-shaped cells that channel water to radial canals

ostia

pores on body surface of sponge

Clade Cnidaria is

radiate animals

Cnidaria tissue level of organization

diploblastic

mesoglea

non-living, jelly-like connective tissue containing few cells

Gastrovascular cavity

both mouth and anus, central digestive cavity

polymorphism

more than one morphology (polyp and medusa)

Polyp

attached to substrate, typically asexual

Medusa

free-floating, typically sexual

nerve net

connects uniformly distributed sensory cells and motor neurons to enable limited number of coordinated movements

bud

product of asexual reproduction

cnidocyte

stinging cells

testes

bud

ovary

gastrovascular cavity

nematocyst

cnidocyte

planula larvae

free swimming, ciliated larvae

hydranth

specialized feeding polyp

gonangium

specialized reproductive polyp

medusa

product of asexual reproduction, released from gonangium when mature

Obelia life cycle

medusae release sperm and egg, forms zygote, forms blastula, matures into planula, budding forms new colony, gonangium forms medusa buds, medusa buds released, medusa buds mature into medusae

oral disc

raised portion of mouth

tentacles

defense and prey capture

mouth

ingestion of food and elimination of indigestible particles

pharynx

muscular portion of gastrovascular cavity for pulling in prey

pedal disc

attaches organism to rocks; can be used for locomotion

ostium

pore that allows circulation of fluids between adjacent body sections

retractor muscles

expand and contract body

gonads

organs for sexual reproduction

radial canal

extension of gastral pouch that radiates out and brings nutrients to rest of body

circular canal

circular extension of gastric pouch that distributes nutrients to outer rim of body

gastric pouch

one of four divisions for gastrovascular cavity for digestion of food

oral arms

defense and prey captures

Aurelia life cycle

medusae release sperm and egg, forms zygote, matures into planula larvae, schyphistoma, matures into strobilia, strobilation (budding process), free swimming ephyra, matures into medusa

Cnidarian Clades

Anthozoa, hydrozoa, schyphozoa, cuboza