Chapter 21, Problem 3WIO

(a)

Summary Introduction

To distinguish:

Animals and other organisms.

Introduction:

Animals come under multicellular organisms having eukaryotic cells. They lack cell wall. They are heterotrophs, acquiring the carbon and energy source from the organic compounds built by other organisms.

(b)

Summary Introduction

To distinguish:

Vertebrates and invertebrates.

Introduction:

Vertebrates are the group of animals which acquires a backbone and spinal cord to support their body. Invertebrates are the group of animals which do not contains backbone.

(c)

Summary Introduction

To distinguish:

Protostomes and deuterostomes.

Introduction:

Protostomes and deuterostomes are used to classify the subkingdom Eumetazoa included in Animalia, on the basis of embryonic development of animals. In protostomes the blastopore develops the mouth, while in deuterostomes it develops the anus.

(d)

Summary Introduction

To distinguish:

Ectotherms and endotherms.

Introduction:

Ectotherm and endotherm in animal classification represents the thermal regulation by the animals. Ectotherms cannot maintain their body temperature as they lack internal mechanisms. Endotherms regulate their body temperature by generating heat from the metabolic activities takes place in them.