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.
Eumatazoa
A subkingdom of animals with true tissues and more complex organization.
Asymmetry
Lack of a specific, balanced arrangement in an organism’s body.
Endoderm
Innermost germ layer in an embryo, giving rise to internal organs.
Mesoderm
Middle germ layer in an embryo, forming muscles and other tissues.
Incomplete digestive tract
A single opening for both ingestion and egestion.
Gastrovascular cavity
A digestive chamber with a single opening, found in some animals.
Complete digestive tract
Two openings, mouth and anus, for food ingestion and elimination.
Segmentation
Division of an organism’s body into repeating, similar segments.
Sponges
Simple, aquatic animals with porous bodies, part of the Porifera phylum.
Flagellated
Possessing whip-like structures (flagella) for movement or feeding.
Mesohyl
Gel-like, acellular matrix in the body of sponges, supporting cells.
Spongocoel
Central cavity in a sponge where water enters for filtration.
Osculum
Large opening in a sponge through which filtered water exits.
Ostia
Small pores in a sponge’s body wall for water intake.
Lophocyte
Specialized cells in sponges responsible for generating collagen fibers.
Collenocyte
Sponge cells that produce collagen, providing structural support to the organism.
Pinacocyte
Flat cells on the outer surface of a sponge’s body.
oocyte
Developing egg cell in a female organism.
Amoebocyte
Mobile cells in sponges responsible for nutrient transport and more.
Sclerocyte
Sponge cells that produce hard, mineralized structures for support.
Oscula
The plural form of “osculum,” which are large openings in sponges for water exit.
Hermaphroditic
Organism having both male and female reproductive organs.
Sperm
Male reproductive cells involved in fertilization.
Eggs
Female reproductive cells, typically larger and non-motile, involved in fertilization.
Cnidarians
Phylum of aquatic animals with specialized stinging cells (cnidocytes).
Medusa
A free-swimming, umbrella-shaped form of some cnidarians, like jellyfish.
Polyp
A sessile, tube-shaped form of some cnidarians, like coral colonies.
Nematocyst
Specialized stinging organelles found in cnidarians, used for defense and capturing prey.
Hydras
Tiny, freshwater cnidarians with simple body structures, often resembling polyps.
Parasitic
Organism that lives off another, often harming its host in the process.
