Lecture 6- Animal Diversity II Flashcards
Do basal animals have general or specific derived traits?
General (they lack more specific derived traits present in most animals)
Phylum Porifera
“to have pores”- sponges
- Least complex animals
- Multicellular
- No symmetry, tissues, organs
- Basal metazoans
Osculum: open end
Spongocoel: central cavity
Water moves through, food filtered out. NOT a digestive cavity- digestion is intracellular
Basal Metazoans
Choanocytes
“collar cells”- feeding cells of sponges (PHYLUM PORIFERA)
Very similar to choanoflagellates
Flagellated
Line spongocoel
Ingest bacteria, food particles
Phylum Cnidaria
- True tissues
- Radial symmetry
- Diploblastic
“Thin” (2 layers)
Gastrovascular cavity
Mostly marine
Basal Eumetazoans
Cnidocytes
Specialized stinging cells, unique to cnidaria
Mostly marine
Cnidarians are basal ___________
Eumetazoans
Porifera are basal __________
Metazoans
Bilateria shared derived traits
Bilateral symmetry, triploblasty
Nephrozoa shared derived traits
Coelom, excretory structures
Eumetazoa shared derived traits
Tissues, symmetry
Metazoa shared derived traits
ECM and multicellularity
Deuterostomia shared derived traits
Deuterostome development (maybe), some with deuterostome development outside this group
Protostomia shared derived traits
Protostome development (maybe), we aren’t sure which type of development is ancestral and which is derived
Deuterostomia phyla
Echinodermata and chordata
Spiralia Clade members
Platyhelminthes, Rotifera, Mollusca, Annelida
Spiralia Clade derived traits
Entirely invertebrates, protostome development (named due to spiral cleavage). Grouped based on DNA
Phylum Platyhelminthes
Dorsoventrally flattened
Acoelomate (derived trait)
Free-living
Parasitic
No body cavity
First in Protostomia and Spiralia Clade
Phylum Rotifera
Within Spiralia Clade
Freshwater/marine, damp soil
Very small
Pseudocoelomates
Have corona: crown of cilia at anterior end
Phylum Mollusca
Coelomates in Spiralia clade
3 main body parts: Mantle, visceral mass, and foot
Mantle: Thin sheet of tissue covering visceral mass, often secretes calcium carbonate shell
Visceral mass: Main body mass, contains viscera (internal organs)
Foot: Structure for locomotion
Radula: Belt of teeth in mouth area, scrapes up food (unique to mollusks)
3 Major Mollusk Clades
Gastropods- “stomach-foot”
Bivalves- “two-shells”
Cephalopods- “head-foot”
Phylum Annelida
Last phyla of Spiralia Clade
“little rings”
Repeated segmentation
Body wall, coelom, many organs divided into segments
Marine, freshwater, soil
Ecdysozoan Clade members
Nematoda, Arthropoda
Ecdysozoa Shared Derived Traits
Ecdysis: Molting/shedding exoskeleton during growth (cicada)
Phylum Nematoda
Within Ecdysozoan clade
Roundworms
Body covered in cuticle
Pseudocoelomates (derived)
Aquatic, soil, parasitic
Things like heartworm
Phylum Arthropoda
Within Ecdysozoan Clade
“joint-foot”
Largest phylum by number of species (contains insects)
Coelomates
Often have deuterostome developmental traits
Arthropod Structure + Derived Traits + costs
Segmented bodies
Often 3 parts- Head, thorax (legs & wings), abdomen
Derived: Jointed appendages
- Often modified, provide motility, allow for feeding, sensory
Derived: Exoskeleton
- Made of chitin and protein (sturdy)
- Jointed
- Covers entire body (protective shell, like grasshopper)
Functions of exoskeleton: Provides protection, prevents desiccation (drying), muscle attachment
Costs to exoskeleton:
- Limits growth (must molt to grow)
- Limits size
