Ch 6 Animal Diversity Flashcards
What are some advantages of multicellularity
Dividing a mass into smaller units greatly increases the surface area available for metabolic activities
What is true about sponges
The advent of multicellularity
They are the simplest multicellular animals
How are sponges different from other metazoans?
The sponges body is an assemblage of cells embedded in and extracellular matrix and supported by A skeleton of spicules and protein
What two grades are metazoans divided into?
Parazoa & eumetazoa
What is the phylum of sponge
Porifera- means porous bearing
What is a placozoan?
Marine organisms they are 2 to 3 mm in size they are made up of dorsal and ventral at the Celia with a synctial middle layer
What is the syncytial middle layer made up of?
Consists of a single plasma membrane with multiple nuclei inside
When does the synctium form?
When cells fuse
How do sponges eat?
Sponges have pores and tiny canals that constitute a filter feeding system for there in active lifestyle
What does sessile mean?
Use water currents to bring food and oxygen and carry away waste
What is a spicule?
Calcium carbonate or silica and collagen
Explain sponges organ system
They don’t have any organs or true tissues
How does sponges reproduce
Disassociated sponge cells can reform a new body
Explain the sponge body in three points
No nervous system or sense organs
Simplest contractile elements
Brightly colored because of pigments in dermal cells
How old are sponges
They can date back to the Cambrian period
What are the four classes or perforans
- Calcarea (having calcareous spicules)
- Dermospongiae (having a skeleton of silieous spicules or spongin or both)
- Hexactinellida (having 6-rayed silocaeus spicules)
- Homoscleromorpha (thin, encrusting, sponges that have simple spicules or none
How many sponge species are there
5000 or more
How many species of freshwater sponge are there
Around 150
Describe the sponge embryos
They are free swimming
Do adult sponges move around?
Adults are always attached to rocks, shells, corals, or other submerged objects
What three things do growth patterns depend on
- Shape of substratum
- Direction/speed of current
- Availability of space
What is a commensal?
Parasites
What are some commensals for sponges?
Crabs, mites, nudibranchs, bryozoans, and fish
Why do sponges have few enemies?
They have an elaborate skeletal frame work, they have a noxious odor, and they taste bad
