Lecture 7 - Non-bilaterians

Question 1

Characteristics of animal phyla

Answer 1

Multicellular, extracellular matrix, no cell wall, cell adhesion, all principles of development, differential gene regulation

Question 2

Non-bilaterian animals

Answer 2

Porifera, ctenophora, cnidaria, placozoa

Question 3

Placozoa common name

Answer 3

Placozoans

Question 4

Ctenophora include

Answer 4

Comb jellies

Question 5

Porifera common name

Answer 5

Sponges

Question 6

Cnidaria example taxa

Answer 6

Jellyfish, corals, anemones, hydroids, sea fans

Question 7

Porifera

Answer 7

Mostly marine species with benthic (bottom of sea floor) and sessile (immobile) adults

Larvae swim via cilia

Asymmetric

Suspension feeding common

Many are symbiotic with photosynthetic organisms

No nervous system/muscles/germ layers

Question 8

Porifera reproduction

Answer 8

Sexual: mostly external fertilization

Aseuxal: fragmentation; budding (gemules)

Question 9

Classes of sponge

Answer 9

Distinguished by spicule type:

1. Demospongia - spongin and/or silica
2. Calcarea - calcium carbonate
3. Hexactinellida - silica

Question 10

Ctenophora

Answer 10

Pelagic (occuring in the open sea)

Propelled by cilia

Cilia are found on iridescent ctenes (comb-like plates)

Predatory- capture prey with colloblast cells

Nerve-net type of nervous system/muscles

Question 11

Ctenophora reproduction

Answer 11

Biradial radial symmetry

Sexual: Mostly hermaphroditic (individual producing both sperm and eggs), this is a type
Most species are self fertile and fertilize mostly with external fertilization

Asexual: by fragmentation

Question 12

Cnidaria

Answer 12

Can be marine or freshwater

Can be benthic or pelagic

Can be sessile or motile

Has a net nerve type nervous system and muscles

Predatory- hunting with cnidocytes (an explosive cell that delivers a sting)

Question 13

Cnidaria reproduction

Answer 13

Often incovles complex life cycles that alternate between sexual and asexual reproduction.

Radial Symmetry

Sexual: mostly external fertilization

Asexual: Budding or fission

Question 14

Placozoa

Answer 14

Benthic marine animals

Herbivores - eat algae

Composed of an outer and inner layer of cells

Propelled by cilia on the bottom cell layer

No nervous system, muscles, or germ layers

Asymmetric

Question 15

Placozoa reproduction

Answer 15

Sexual: no genetic evidence observed for this

Asexual: budding