Bio 123: PP11 Material Flashcards
What are the major characteristics of Porifera (sponges)?
1) Body has pores, canals, and chambers that form a system of water currents to helps the sponges get food and oxygen
2)Are all aquatic
3)Typically no symmetry
4)Interior is lined with choanocytes that create water currents
5) Its skeletal structure contains fibrillar collagen (spongin) and crystalline spicules (protection)
6) No organs or true tissues - excretion and respiration is done through diffusion
7) No nervous system, some electrical stimulation
8) Sessile and attached to substratum
9)Asexual reproduction through budding and sexual reproduction
Crystalline Spicules
Pieces of silica or calcium that are used to defer predators and provides structural support
Spongin
Fibrous structures that provides structure and support
Budding
How sponges reproduce asexually. Pieces of the sponge break off and settles down somewhere else and begins to undergo meiosis.
What is the phylum of radial animals?
Cnidaria
What are the major characteristics of cnidaria?
1) Extensible tentacles that are used for feeding and protection
2)Nematocysts
3) Entirely aquatic
4)Radial Symmetry
5)2 body types -polyps and medusae
6) Extracellular digestion
7) Presence of a nerve net
8) Asexual and sexual reproduction
9)No excretory or respiratory system - diffusion accomplishes these processes.
10) Has tissue and is diploblastic
Nematocysts
Stinging cells on the tentacles that has some types of venom that paralyzes its prey. Also give the species structure and protection
Polyps
Are sessile but still have tentacles and a mouth
Medusae
Takes on the classic jellyfish shape and are motile
Extracellular digestion
Excrete digestive enzymes into the environment
Nerve Net
It is a diffuse mesh of nerve cells that take part in simple reflex pathways. The nerve cells interact with sensory and contractile cells
What are the four major classes of Cnidaria?
-Hydrozoa - Hydras
-Scyphozoa and Cubozoa - Jellyfish
-Anthozoa - Sea anemones, corals, and sea ferns
Hydrozoa
Take on two life forms, the polyp phase and medusae phase. Are typically very small
What is the life cycle of Hydrozoa
-First we see a polyp phase that had an obelia colony
-The Obelia colony has hydrotheca and Gonotheca which are buds on the colony
-The hydrotheca is responsible for food and protection
-The gonotheca is used for asexual reproduction and create medusae
-These medusae are hermaphrodite which produces both eggs and sperm
-When an egg and sperm cell come together they produce a zygote
-This forms into a Blastula which then turns into a free-swimming planula larva
-The larva settles down to start a new colony and the cycle repeats.
Scyphozoa
Takes on the classic jellyfish medusae shape