Animal Diversity: III Flashcards
What is the symmetry of adults in Phylum Echinodermata?
Adults have pentaradial symmetry around an oral/aboral axis.
What structure do adults in Phylum Echinodermata have?
Five arms, or rays, extending out from a central disc.
What powers the tube-feet in Phylum Echinodermata?
Water-vascular system.
What are the hallmark characteristics of Phylum Chordata?
- Notochord
- Pharyngeal slits
- Dorsal nerve cord
- Postanal tail
Always present in some embryonic stage, but not necessarily in adults.
What is the function of the muscular postanal tail in Phylum Chordata?
Evolved for propulsion in an aquatic environment and has various functions in terrestrial vertebrates.
What are the three subphyla of Phylum Chordata?
- Cephalochordata
- Urochordata
- Vertebrata
What are examples of Vertebrata?
- Jawless fish – lampreys and hagfish
- Cartilaginous fish – sharks and rays
- Bony-fish
What is the skeleton composition of Chondrichthyes?
Skeleton composed of cartilage – no bone – partly calcified.
What are the two types of bony fish?
Either ‘ray-finned’ or ‘lobe-finned’ with lungs or lung derivatives (swim-bladder).
What percentage of all vertebrate species are ray-finned fish?
About half of all vertebrate species.
When did vertebrates colonize land?
Approximately 400,000,000 years ago.
What adaptations were necessary for vertebrates to colonize land?
- Ability to breathe air
- Stronger limbs and skeleton
What adaptations did some fish already have for life on land?
- Air-filled cavity connected to pharynx (swim bladder)
- Paired, modified fins for support and crawling.
Why did some fish leave the water permanently?
Fresh-water habitats threatened by evaporation and oxygen depletion.
What advantages did leaving water provide to vertebrates?
New habitats, new food sources, safer shelter for eggs and young, and less competition.
What are non-fish vertebrates called?
Tetrapods.
What are examples of tetrapods?
- Amphibians
- Birds
- Reptiles
- Mammals
What are amphibians?
Tetrapods that still live in close association with aquatic environments.
What are amniotes?
Tetrapods with an amniotic egg, allowing embryos to develop.
What are some adaptations to terrestrial life in amniotes?
- Keratinized scales to protect skin and resist desiccation
- Feathers, nails, and hair derived from reptilian scales.
What is the temperature regulation of most reptiles?
Ectothermic – ‘cold blooded’ – body temperature is dependent on the environment.
What is the temperature regulation of birds, mammals, and some reptiles?
Endothermic – ‘warm blooded’ – body temperature is regulated by their metabolism.
What defines mammals?
Animals with hair and mammary glands.
