Lab 7 - Invertebrates

What is a body plan?

A set of morphological and developmental traits that can characterize the anatomical organization of an animal

What are the four main aspects of a body plan?

Body symmetry, tissues, body cavities, and development.

What are the two types of symmetry?

Radial and bilateral

What do bilateral organisms exhibit?

Cephalization, which is the concentration of sensory structures at the anterior end of an organism.

What type of organisms most likely have radial symmetry?

Sessile or slow moving.

What type of animals exhibit bilateral symmetry?

Animals that are more motile, so that they can detect food or predators in front of them .

What are germ layers?

The origins of musccle tissue and muscle formation

What is formed after the zygote undergoes repeated mitotic divisions?

A blastula.

What does the blastula go through and what does it form?

It goes through invagination and gastrulation which is folding within itself to create the gastrula

What are the parts of the gastrula?

• Ectoderm

• Endoderm

What is the ectoderm?

Covers the outside of the gastrula, and gives rise to the epidermis, and central nervous system

What is the endoderm?

Lines the newly formed archenteron giving rise to lining of gut and organs

What is a special third germ layer that All Eumatozoans except for Cnidarians and Ctenophores?

The mesoderm which is in between both layers. This forms the muscle.

What are animals with only the ectoderm and endoderm called?

Diploblastic. They don’t have complex muscles resulting in simple modes of locomotion.

What are animals called when they have a mesoderm?

Tripoblastic where muscle is developed through this layer.

What is a coelom?

The body cavity is lined with mesoderm on both sides and the gut is suppored by mesentery tissues and muscles.

What is a hemocoel?

The body cavity is a space between the endodermal gut tube and the mesoderm body wall.

What are compact organisms?

Organisms that have no fluid filled cavity between the gut and the body wall where they have a region that is packed with cells from the mesoderm.

How does the body cavity help with tripoblastic invertebrates without rigid skeleton?

Provides structure and helps with locomotion. It is fluid held under pressure in the body cavity.

What are metameres?

A series of segments or repeated units down the length of the animal.

What is the process of tagmantization?

When the segments fuse or develop different shapes in specialized regions for specialized functions.

What is a head tagmata used for?

Search and consuming food.

What is a thorax used for?

Locomotion or for the heart and lung function.

What is an abdomen tagmata specialized for?

Digestion and reproduction

What do bilateral animals have?

They have one pair of appendages per segment.

What were pairs of appendages used for?

Legs, antennae, mouthparts, claws, flaps for swimming, wings, or mating structures

What are characteristics of phylum Cnidaria?

• Radial

• Two Germ Layers

• No body cavity

• Without segmentation

What are characteristics of platyhelminthes?

• Bilateral

• Three germ layers

• Acoelomate

• No segmentation

What are characteristics of mollusca?

• Bilateral

• Three germ layers

• Coelomate

• No Segmentation

What are the characteristics of phyla annelida?

• Bilateral

• Three germ layers

• Coelomate

• Metamers segmentation

What are the characteristics of phyla Nematoda?

• Bilateral

• three germ layers

• Hemocoel

• No segmentation

What are the characteristics of Arthropoda?

• Bilateral

• Three germ layers

• Coelomate

• Tagmata

What is protosomal development?

Spiral, determinate, cleviage, that is split. The first things that form are the mouth through the development of the blastospore. Mouth develops from blastospore

What is deuterostomal development?

Radial, indeterminate clevae, enterocoleous formation of the coelom in which the mesoderm forms from an outpacking of the embyonic gut tube. This is where the mouth forms second. Anus develops from blastospore first and then the mouth

What are characteristics of phylum Echinodermata?

• Five part radial symmetry

• Calcareous endoskeleton

What do the echnodermata use thier water vascular system for?

First as a way to feed with non motile ancestors, but now has been modified the vascular system for locomotion.

What are the four characteristics of Dueterostomes Chordates?

• Notochord

• Dorsal hollow nerve cord

• Pharyngeal slits

• Post Anal Tail

What is the notichord used for?

a longitudinal, endoskeletal rod that gives strength and elasticity to the body. 

What is the dorsal hollow nerve cord?

a longitudinal, fluid-filled nerve cord that runs along the back of the body (dorsally) just above the notochord. This is called the spinal cord in vertebrates

What are pharyngeal slits used for?

lateral openings in the foregut (pharynx) of chordates. These slits were originally used for filter feeding. In aquatic vertebrates, these are specialized for gas exchange whereas in land vertebrates, they are only seen in the embryo

What is a post anal tail?

a muscular tail that extends past the anal opening