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