Kingdom Animalia page 657 What is an animal?

What are characteristics of animals? 3zzg 3zzg

Characteristics of animals 1. Multicellular – Different cells specialize to perform certain functions – the more evolved the higher the degree of specialization – As specialization increases, so does complexity and this enables animals to adjust better to their environments.

Degree of specialization a.Cells which are grouped together to form b.Tissues such as blood, bone, muscle, nerve c. Organs: liver, stomach d. Organ systems: circulatory, digestive, reproductive

Characteristics continued 2.Eukaryotic 3.Heterotrophic - ingest and then digest inside body 4.Most are motile (All are motile for at least part of their life cycles)

Characteristics continued 5. Phyla in the animal kingdom are classified according to evolutionary development. a. 2 subkingdoms: parazoa (less evolved) and metazoa

b. Also grouped by whether they are: vertebrates or

invertebrates (95%)

Animals carry out the following essential functions and each has adaptations which allow it to do so : Feeding – Ingest – herbivores, carnivores, omnivores Respiration – Oxygen in; carbon dioxide out

Circulation – Diffusion in small, aquatic – Larger animals have a circulatory system.

Excretion – Main waste product of cells is ammonia (contains nitrogen) – Most animals have an excretory system that eliminates ammonia or changes it into a less toxic substance and then gets rid of it.

Response – Respond to events in their environments using specialized nerve cells. – Range from no nerve cells to cephalization to extremely specialized nervous system

Movement – Majority of animals are motile (capture food) – Some may be sessile as adults but move in early development. – When sessile, they attach themselves to a spot and capture food as it passes by.

Reproduction – Sexual (haploid gametes) which maintains genetic diversity – Some are hermaphrodites – In some cases, may be asexual, which allows for rapid reproduction

Also see page 660

Early development – page 661 Zygote = fertilized egg Blastula = hollow ball of cells Blastopore = blastula folds in on itself, creating a tube which becomes the digestive tract.

Copyright Pearson Prentice Hall The zygote undergoes a series of divisions to form a blastula, a hollow ball of cells.

Copyright Pearson Prentice Hall A protostome is an animal whose mouth is formed from the blastopore. Most invertebrate animals are protostomes. Blastopore Endoderm Mesoderm Blastopore becomes mouth Anus Ectoderm

Copyright Pearson Prentice Hall Trends in Animal Evolution A deuterostome is an animal whose anus is formed from the blastopore. The anus is the opening through which wastes leave the digestive tract. Blastopore becomes anus Mouth Ectoderm Mesoderm Endoderm Blastopore

Copyright Pearson Prentice Hall Trends in Animal Evolution Echinoderms and vertebrates are both deuterostomes.

Cells differentiate into three layers called germ cells. Endoderm = inner layer, develops into linings of digestive tract and respiratory system. Mesoderm = middle layer which gives rise to muscles and much of the circulatory, reproductive and excretory systems. Ectoderm = outer layer gives rise to sense organs, nerves, and the outer layer of skin.

Copyright Pearson Prentice Hall Trends in Animal Evolution The cells of the endoderm, or innermost germ layer, develop into the linings of the digestive tract and much of the respiratory system. Only the label “endoderm” should appear on this slide. Endoderm

Copyright Pearson Prentice Hall Trends in Animal Evolution The cells of the mesoderm, or middle layer, develop into muscles and much of the circulatory, reproductive, and excretory organ systems. Mesoderm

Copyright Pearson Prentice Hall Trends in Animal Evolution The ectoderm, or outermost layer, develops into the sense organs, nerves, and the outer layer of the skin. Ectoderm

Radial Symmetry

Bilateral symmetry