Ch 27 Summary

Introduction to Animals

Ch 27 Review

Characteristics of Animals

Section 1

All animals share these general features:

• heterotrophy

• mobility

• multicellularity

• sexual reproduction

• diploidy

• the absence of a cell wall

• blastula formation

  cells organized as tissues

Body Symmetry

• Radial symmetry- have body parts arranges around a central axis

• Bilateral symmetry- distinct right and left half, and most display cephalization

Internal Body Cavity

• Three basic body plans

• Acoelomate- no body cavity

• Pseudocoelomate- body cavity located between the mesoderm and endoderm

• Coelomate- [true coelom] body cavity located entirely within the mesoderm

Body Segmentation

• Segmentation in body structure underlies the organization of all advanced animals

Kinds of Animals

• There are about 35 animal phyla, which contain an extraordinary range of body forms and body systems

• Scientists classify animals using several different types of data, which include comparing anatomy and physiology, patterns of development, and DNA.

• The animal kingdom is divided into two groups: vertebrates and invertebrates

Animal Body Systems

Section 2

Tissues and Organs

• Body systems are specialized to carry out different tasks

• Simple animals have a gastrovascular cavity with only one opening, while more complex animals have a one-way gut

• Simple animals exchange gases directly through their skin

• More complex aquatic animals use gills, while terrestrial animals use a a variety of respiratory organs (such as lungs)

Multiple Choice

Body __________ are specialized to carry out different tasks

• parts

• systems

• locations

• markers

Tissues and Organs

• Open circulatory system- circulatory fluid leaves the vessels and enters the body cavity

• Closed circulatory system- blood remains in vessels

• Simple animals have little coordination among their nerve cells

• Complex animals have nerve cords and a brain with associated sensory structures

• For most animals eliminating wastes is linked to maintaining the correct water balance in their body

Reproductive Strategies

• Asexual reproductive methods- fragmentation, splitting in two, and parthenogenisis

• Sexual reproduction- male and female gametes combine to form a new individual