BIOL 112 - Lab 17 - The Deuterostomes: Phyla Echinodermata and Chordata - Lab

how can you differentiate a fertilized egg from an unfertilized egg

an egg that is fertilized lacks the appearance of an ovbious nucleue while a nucleus can be seen in an unfertilized egg

what is the fertilization envelope

the fertilization envelope helps to block the penetration of the egg when more sperm appears than necessary

is the four-cell stage embryo overall size, smaller, or the same size as the fertilized egg?

it is going to remain the same size as the fertilized egg because during division, only the amount of cells increases, nothing happens to the size

how can you tell the difference between "early" and "late" blastula?

by the sizes of the blastulas; the later blastula is going to be larger have more cells, than the earlier blastula

what are blastomeres?

individual cells that are developed during the cleavage of the egg fertilization

what is the blastocoel?

fluid-filled interior space of the blastula

what does the blastopore become in the adult?

the anu

what does the archenteron develop into in the adult?

in adults, the archenteron will develop into the mouth

the bipinnaria larva displays what type of body symmetry?

bilateral symmetry

notice the five paired rows of perforations (pores) in the urchin shell. what purposes do these small holes serve? what wold you find coming out of them?

these small holes allow their appendages (tube feet in this case) to come out

each ampulla is attached to a tube foot that emerges form the other side of the sea star. on a living sea star, each tube foot is small and seems fragile. how can you explain their ability to hold a sea star tightly onto a rock even in strong waves?

sea stars have many ampulla attached to their tube foot and these ampulla serve as suctions that help them stay attached to many surfaces

which stage of the tunicates life cycle displaces all four chordate characteristics?

the larval stage

tetrapods, such as amphibians, reptiles, and mammals, are terrestrial relatives of the bony fish. which of your appendages are homologous to the pectoral fins of a perch?

forelimbs

which of your appendages is homologous to the pelvic fins of a perch?

hindlimbs

ray-finned fishes are the largest group of vertebrates

how many different species are there?

greater than 20.000

when fish are swimming what part of their anatomy provides speed (forward motion)?

caudal fin (tail)

when fish are swimming what part of their anatomy provides maneuverability?

pectoral and pelvic fin

the cloaca is an opening into which body system(s)?

urinary/digestive tract and reproductive tract

what function do the nostrils serve in a fish?

chemosensory; tasting, smelling

what is the function of the lateral line?

senses changes in pressure; sensory system (works well in water)

the operculum covers the gills, it protects the gills, but what else does it do?

helps with breathing by pumping water over their gills and allowing the to get oxygen to their tissues

what are fish scales made of?

thin type of bone, lying underneath the skin

how and where are perch eggs fertilized

they are fertilized externally and fertilization occurs in the water

in the perch, eggs exit through which opening

they exit through the cloaca

what has the swim bladder evolved into in other animals?

the swim bladder evolved into the lungs in other animals

what is the function of the spleen

the spleen is involved in immune function

how does the size of a fish heart compare to the heart of invertebrates?

it is larger in comparison to the heart of other invertebrates

starting at the atrium, trace the path of blood through the fish body

it flows in a single circuit, entering the atrium from the body tissues, flows to the ventricle and is pumped to the gills to obtain oxygen

you can tell male from female by the appearance of the gonads. how do ovaries look different from testes?

ovaries are a red/pink/orange-colored sac filled with eggs while the testes are a white, elongated, smooth body pair

why do male perch need to make a lot of sperm

because they fertilize externally