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 – As specialization increases, so does complexity and this enables animals to adjust better to their environments.

Characteristics continued 2. Eukaryotic 3.Heterotrophic - ingest and then digest inside body 4.Most are motile

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.

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 – In some cases, may be asexual, which allows for rapid reproduction

Also see page 660

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

Early development – page 661 Zygote = fertilized egg Blastula = hollow ball of cells Blastopore = blastula folds in on itself, creating a tube – Protostome = mouth is formed by blastopore (eat and poop from same hole) – Deuterostome = anus is formed by blastopore (mouth is formed later) (eat and poop from different holes) Ex. echinoderms and all vertebrates.

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 stystems. Ectoderm = outer layer gives rise to sense organs, nerves, and the outer layer of skin.

Radial Symmetry

Bilateral symmetry