Chapter 32 terms/concepts

Question 1

Key characteristics of animals and their life cycles

Answer 1

The are multicellular, heterotrophic and eukaryotes. Nervous and muscle tissue are defining characteristics of animals

Most animals reproduce sexually. Zygote undergoes rapid cell division called cleavage, which leads to the formation of a multicellular, hollow blastula.

Gratulation occurs, forming a gastrula with different layers of embryonic tissues

Question 2

Differentiating between different types of animal body plans

Answer 2

a body plan is a set of morphological and developmental traits

Radial symmetry: have a top and a bottom, but no front and back, left or right

Bilateral symmetry: have a dorsal (top) side, and a ventral (bottom) side. They also have a right and left side, and anterior and posterior back ends. Many have sensory equipment, such as a brain, concentrated in their anterior end

Question 3

ID and describe the different germ layers

Answer 3

Endoderm: innermost germ layer and lines develoing digestive tube

Mesoderm: middle germ layer between endoderm and ectoderm; gives rise to the skeleton, muscle, heart and bones

Ectoderm: germ layer that covers the embryo’s surface

Question 4

Diploblastic vs. triploblastic animals

Answer 4

Diploblastic animals: have only ectoderm and endo derm (which includes cnidarians like hydra)

Triploblastic animals: have intermediate tissue layer called the mesoderm, along with ectoderm and endoderm layers

Question 5

Bilateral symmetrical animals are diploblastic or triploblastic?

Answer 5

Triploblastic

Question 6

Coleum and pseudocoleum similarities and differences

Answer 6

A coleum (body cavity) and a pseudocolum are both derived from the mesoderm

The pseudocoleum, however, is also derived from the endoderm along with the mesoderm. A true coleum would just be derived from the mesoderm

Question 7

Functions of a body cavity

Answer 7

Supports/cushions organs, holds them in place, and allows them to move freely within the confined space of the organism. Also protects the organs

Question 8

Current views on animal phylogenetic trees (5 views)

Answer 8

1. All animals share a common ancestor
2. Sponges are a sister group to all other animals
3. Eumetazoa (“true animals”) are animals with tissues
4. Most animals belong to the clade Bilateria
5. There are 3 major clades of bilaterian animals, all are invertebrates except chordates, which include vertebrates (animals with backbone)

Question 9

Three major Eumetazoan groups: the Deuterostomia, Ecdysozoa, and Lophtrochozoa

Answer 9

Ecdysozoans: invertebrates, and many members secrete their external skeletons

Lophotochozoans: also invertebrates, and some have a feeding structure called the lophophore

Deuterostomia: includes hemichordates (acorn worms), echinoderms (sea stars and relatives) and chordates. Both vertebrates and invertebrates