Deuterostomes, Echinoderms, Chordates, and Vertebrates (FB)

Flashcards covering Deuterostomes, Echinodermata, Chordata, Fish, Amphibians, Reptiles, Birds, and Mammals.

Deuterostome Blastopore Fate

Becomes the anus; the mouth forms second.

Deuterostome Cleavage

Radial, indeterminate.

Deuterostome Coelom Formation

By out-pocketing of the archenteron (enterocoely).

Deuterostome Germ Layers and Cavity

Triploblastic, coelomate.

Deuterostome Symmetry

Bilateral (embryos/larvae); some adults switch to radial.

Deuterostome Skeleton Type

Internal endoskeleton (e.g., vertebrate bone, echinoderm CaCO₃ plates).

Sea Lamprey Research focus

Spinal-cord regeneration, immune evolution, developmental gene regulation.

Sea Squirt (tunicate) as Model

Transparent larvae; real-time gene expression; notochord only in larval stage.

Zebrafish Research Uses (only fish chosen)

Cancer studies, inner-ear hair-cell repair, vertebrate development; fast, transparent embryos.

Echinoderm Adult vs. Larval Symmetry

Adults = pentaradial; larvae = bilateral.

Echinoderm Endoskeleton Material

Calcium-carbonate plates (may be spiny or fused).

Echinoderm Hallmarks (4 traits)

True coelom, water vascular system, tube feet, high regeneration capacity.

Do echinoderms have a brain?

No brain; nerve ring + radial nerves, no centralised head.

Echinoderm Excretory Organs

None specialised; waste diffuses across body surfaces.

Entry point of seawater into the water-vascular system.

Madreporite (sieve plate).

Water-Vascular Canals Sequence from madreporite to tube feet.

Madreporite → stone canal → ring canal → radial canals → lateral canals → tube feet ampullae.

How does a tube foot extend and retract?

Ampulla contracts to extend; relaxes to retract.

Tube Feet Functions besides walking

Attachment to substrate & food handling / gas exchange.

One difference between echinoderm endoskeleton & arthropod exoskeleton.

Echinoderm plates are internal, living tissue; arthropod exoskeleton is external, must be shed.

List the four phylum chordate hallmarks.

Notochord, dorsal hollow nerve cord, pharyngeal slits, post-anal tail.

Which subphylum keeps all four traits for life?

Cephalochordata (lancelets).

Adult tunicate retains which chordate trait?

Pharyngeal slits only.

What replaces the notochord in vertebrates?

Vertebral column.

universal fish respiratory organ.

Gills.

Skeleton material of Class Chondrichthyes.

Cartilage (sharks, rays, skates).

Why bony fishes need a swim bladder or lung.

Buoyancy control; also air-breathing in some (lungfish).

Amphibian dual-life explanation.

Aquatic gilled larvae → air-breathing adults with lungs & legs.

Key land adaptations of amphibians (name two).

Lungs, stronger limbs & skeleton, moist skin gas exchange, eyelids / tympanic membrane.

Main reptile skin adaptation for dryness.

Keratinised scales reduce water loss.

Name the four membranes of an amniotic egg.

Amnion, Chorion, Allantois, Yolk sac.

Define parietal eye.

Light-sensitive “third eye” on head of some lizards—detects day length & temperature.

Carapace vs plastron in turtles.

Carapace = dorsal shell, plastron = ventral shell; fused bones + keratin scutes.

Two feather functions besides flight.

Insulation & display/communication.

How do bird lungs achieve one-way airflow?

Air sacs push fresh air through lungs on both inhalation & exhalation.

Name three skeletal/lightweight adaptations for flight.

Hollow bones, fused bones (reduced count), keeled sternum for flight-muscle attachment.

Circulatory advantage birds share with mammals.

Four-chambered heart—complete separation of oxygenated & deoxygenated blood.

Two unique mammalian traits.

Hair/fur & mammary glands.

Distinguish monotremes vs marsupials vs placentals in one phrase.

Monotremes lay eggs; marsupials short gestation, pouch development; placentals long gestation via true placenta.

Shark heart chambers & skeleton type.

2-chambered heart; cartilage skeleton.

Goldfish buoyancy organ.

Swim bladder.

Frog respiratory shift from larva to adult.

Gills → lungs + skin diffusion.

Unique reptile with 4-chambered heart (ectotherm).

Crocodile.

Turtle skeletal adaptation.

Bony shell (carapace + plastron).

Mammal (dog) thermal strategy & heart design.

Endothermic; 4-chambered heart.