Chapter Six: Classification - Invertebrates Flashcards
Three Types of Symmetry
- Asymmetrical: no particular symmetry
- Radial symmetry: circular organization, bisect on any plane
- Bilateral symmetry: left and right halves, mirror image sides
Three Germ Layers
- Ectoderm
- Endoderm
- Mesoderm
Three Types of Body Symmetry
- Acoelomate: no body cavity, solid body (no germ layers)
- Psuedocoelomate: three germ layers, cavity partially lined with mesoderm
- Coelomate: three germ layers, mesoderm covering inner body cavity
Budding
Asexual reproduction; outgrowth of the parent breaks off and forms a new individual
Hermaphrodite
Both sexes in one individual; has both egg and sperm
Internal Fertilization
Occurs interiorly within the female
External Fertilization
Occurs outside the organism
Circulation of Porifera
- water enters in through pores, circulates throughout body
- choanocytes trap and digest food
- food absorbed and transported by amoebocytes
Structure and Function of a Choanocyte
- flagellated cell with collar cell
- Filter feeder - beats and pulls in food from circulating water
Types of Sponges and their Spicules (3)
Spicules as as a skeleton
- Glass Sponges: silica
- Chalk Sponges: calcium carbonate
- Proteinacous Sponges: Spongin fibres
Amoebocyte
Found in middle layer of sponge wall. Picks up food from choanocytes and distributes throughout sponge.
Role of a Gastrovascular Cavity in Digestion
Sac-like cavity with one opening; food enters and is digested. Digested food absorbed by diffusion.
Three Cell Layers in Cnidaria
- Epidermis
- Gastrodermis
- Mesoglea
Nematocyst
Coiled stinger used to shoot and paralyze prey. Found in Cnidaria
Two basic body forms of Cnidaria
- Polyps
2. Medusae
Why are jellyfish, coral, and hydrozoans in the same phylum?
Life cycles alternate between two forms: medusae in jellyfish, polyp in coral, both in hydra
Main Features of Platyhelminthes (3)
- bilateral symmetry
- three germ layers
- acoelomate
Three Layers of Platyhelminthes
- Ectoderm
- Mesoderm
- Endoderm
Nervous System of Cnidarians
Diffuse nerve net: no central nervous system, all nerves interconnected
Three Classes of Platyheminthes
- Tapeworms
- Planarians
- Flukes
Flame Cell
Removes waste to excretory pores. Found in playheminthes
Life Cycle of a Liver Fluke
- Eggs pass out in human feces and enters snail
- Larva burrows into fish muscle
- Fish eaten by humans and larva grows to adult in bile duct
Role of a Cyst in Endoparasites
Calcium shell that protects parasite from being destroyed by host.
How does a tapeworm attach to a host’s intestine?
- scolex attaches to host in intestine
- feeds on host’s digestive food
Nervous System of Platyheminthes
Ladder-like nervous system: anterior ganglia and eyespots (chemosensitive)
Life Cycle of a Tapeworm
- Host eats fertilized egg
2. Hatches in its intestine and produces proglottid that leaves through feces
Three Classes Of Phylum Mollusca
- Bivalve
- Gastropod
- Cephlopod
Locomotion in Mollusca
- Flat foot: Gastropod
- Hatchet foot: Bivalve
- Jet propulsion: Cephlopod
Radula
Found in cephlopods; calcified rasping organ used for feeding.
Mollusca Respiration
- Gills
2. Lung-like mantle (terrestrial gastropods)
Mollusca Reproduction
Separate sexes, produces trochophore larva (bivalves)
Mollusca Nervous Systems (3)
- Brain and Nerves: cephlopods
- Three Separate Ganglia: bivalves
- Cerebral Ganglia (long nerve ending): gastropods
Bivalve Digestion
Filter feeders: water enters through incurrent siphon, which moves water in spout of individual
Three Classes of Annelida
- Earthworms
- Leeches
- Marine worms
Nephridia
Excretory tube found in annelids
Parapodia
Paired appendage found in each segment of an annelid
Setae
Locomotive organ used to move through ground in annelids
Digestion in Annelids
- food enters through mouth by muscular movement
- typhosole: digestion over large surface area
- typhosole expands and contracts on dorsal surface of intestine
Circulation in Annelids
- closed circulatory system with five hearts
- moves anteriorly over dorsal vessel
- heart pumps blood through ventral blood vessel, branching off as it moves anteriorly, then posteriorly
Four Main Features of Arthropoda
- Jointed Appendages
- Exoskeleton of chitin
- Three body regions
- Well-developed nervous system
Features of the Head of Arthropoda
- compound eyes, 5 pairs of appendages
- 2 antennae 3 mouth parts
Features of the Thorax of Arthropoda
- 5 appendages: walking legs
- 1st appendage a claw
Features of the Abdomen of Arthropoda
- swimmerets
- last two segments have uropod and telson
Digestion of Arthropoda
- 2 part stomach
- green glands for waste excretion
Vascular System of Arthropoda
-heart pumps blood with hemocyanin into hemocoel
Reproduction of Arthropoda
- separate sexes
- sperm transfer by first pair of swimmerets
- ovaries open at base of third walking legs
- eggs attach to swimmerets of female
General External Features of a Grasshopper (3)
- Head: compound eyes, antennae, mouthparts
- Thorax: 3 pairs of legs, wings if present
- Abdomen: contains internal organs
How is a grasshopper’s reproduction adapted for terrestrial life? (4)
- internal fertilization (protected)
- female has seminal receptacles which store sperm; keeps from drying out
- female deposits eggs into ground
