Bio. II lecture Exam 3 Flashcards
Single-cell ancestor
Common, primitive cell from which all life evolved.
Multicellular
Organisms composed of multiple specialized cells working together for functions.
Porifera
Phylum of aquatic animals, including sponges, with porous body structures.
Tissues
Groups of similar cells performing specific functions in multicellular organisms.
Cnidarian
Phylum of aquatic animals with stinging cells, including jellyfish and corals.
Radial symmetry
Symmetry where body parts radiate from a central point.
Bilateral symmetry
A type of symmetry where an organism can be divided into two equal, mirror-image halves.
Protostomes
Animals whose mouth develops before the anus during embryonic development.
Platyhelminthes
Flatworms, a phylum of soft-bodied, unsegmented invertebrates with simple organ systems.
Acoelom
Organism lacking a true body cavity between the gut and body wall.
Mollusks
Diverse phylum of invertebrates with soft bodies and often hard shells.
Annelids
Phylum of segmented worms with a coelom and bristle-like structures.
Segmentation and Coelom
Division of an organism’s body into repeating, similar segments.
Fluid-filled body cavity in some animals, cushions and supports organs.
Nematodes
Roundworms, a diverse phylum of unsegmented, cylindrical, and parasitic worms.
Pseudocoelom
A body cavity partially lined with mesoderm, found in some animals.
Arthropods
Diverse phylum of invertebrates, including insects, spiders, and crustaceans.
Deuterostomes
A major group of animals where the anus forms before the mouth during embryonic development.
Echinoderms
Marine animals with radial symmetry, like sea stars and sea urchins.
Chordates
A phylum including animals with a notochord, such as vertebrates.
Parazoa
A subkingdom of animals, including sponges, with primitive body organization.