Test 4

What are the two germ layers found in diploblasts?

Ectoderm and endoderm.

Which organisms are considered triploblasts?

All other animals that have three germ layers: ectoderm, mesoderm, and endoderm.

What is an acoelomate organism?

An organism with no body cavity, such as flatworms.

Define pseudocoelomate.

An organism with a body cavity located between the mesoderm and endoderm, for example, nematodes.

What characterizes a coelomate organism?

A coelomate organism has a body cavity fully within the mesoderm, such as annelids, arthropods, and vertebrates.

What is the key difference between protostomes and deuterostomes?

In protostomes, the mouth develops first, while in deuterostomes, the anus develops first.

Give an example of a protostome.

Annelids, arthropods, or mollusks.

What develops from the ectoderm layer?

Skin and the nervous system.

What does the mesoderm layer develop into?

Muscles, bones, and the circulatory system.

What is formed from the endoderm layer?

Gut lining and organs.

What kind of symmetry do adult echinoderms display?

Radial symmetry.

Describe the larval symmetry of echinoderms.

Bilateral symmetry.

What system do echinoderms use for movement?

Water vascular system, featuring tube feet.

What are Hox genes responsible for?

They are master regulators of body plan determining the head-tail axis and segment identity.

What distinguishes mammals from amphibians?

Mammals have hair, are endothermic, and possess mammary glands.

Describe amphibian respiration.

Amphibians utilize both cutaneous (skin) and lung breathing.

How do reptiles differ in terms of respiration compared to amphibians?

Reptiles rely solely on lungs for respiration.

What is a key structural difference in the hearing mechanism of mammals versus reptiles?

Mammals have three middle ear bones, while reptiles have only one bone.

What is the function of the amnion in amniotic eggs?

It provides a fluid cushion.

What is the purpose of the chorion in amniotic eggs?

It facilitates gas exchange.

What does the allantois store in amniotic eggs?

Waste.

What is the role of the yolk sac in amniotic eggs?

It provides nutrients.

How do freshwater salmon regulate their osmotic balance?

They produce dilute urine to eliminate excess water.

What mechanism do saltwater fish use to conserve water?

They excrete concentrated urine.

What is the role of the rumen in digestion for certain animals?

It is the first chamber of a four-chambered stomach, aiding microbial fermentation.

Define pseudorumen.

A modified stomach in some animals without a true rumen structure.

How do both fungi and mammals store energy?

They store glycogen as a short-term energy source.

What is an example of negative feedback in physiology?

The process by which insulin is released to lower blood glucose levels.

What is the function of rods in vision?

They are responsible for night vision and black and white perception.

What is the function of cones in vision?

They detect color and detail, requiring more light.

How did the first jaws evolve in animals?

They evolved from gill arches in Placoderms, an extinct group of jawed fish.

What is a notable feature of avian respiration?

Most efficient breathing mechanism with unidirectional airflow via air sacs.

What characterizes epithelial tissue?

It is tightly packed, covers surfaces, lines organs, and has little extracellular matrix.

What does the carrier constant in the Michaelis-Menten concept refer to?

The affinity of a transporter for its substrate, impacting the rate of diffusion across membranes.

List shared features of Ctenophora and Cnidaria.

Both exhibit radial symmetry and are diploblastic.

What sets Cnidaria apart from Ctenophora?

Cnidaria possess stinging cells (cnidocytes), whereas Ctenophora do not.