Introduction to AnimalsIntroduction to Animals1.1. HeterotrophsHeterotrophs2.2. MulticellularMulticellular3.3. Most are Mobile Most are Mobile 4.4. Most reproduce sexually/ few can asexually reproduceMost reproduce sexually/ few can asexually reproduce5.5. No cell wallNo cell wall6.6. Most (except sponges) have tissues. These are groups of cells that work Most (except sponges) have tissues. These are groups of cells that work

together to perform a specific function. Ex: nerve tissue sends/receives together to perform a specific function. Ex: nerve tissue sends/receives signalssignals

7.7. Formation of a Blastula (except sponges): a zygote that has gone Formation of a Blastula (except sponges): a zygote that has gone through cell division until a ball of cells is formed. This ball of cells through cell division until a ball of cells is formed. This ball of cells (blastula) keeps dividing until 3 distinct layers form. These layers will (blastula) keeps dividing until 3 distinct layers form. These layers will form into tissues and organs in the adult body. form into tissues and organs in the adult body.

a. ectoderm: outer-layer- outer layer of skin, nervous system, a. ectoderm: outer-layer- outer layer of skin, nervous system, sense organssense organs

b. endoderm: inner-layer- lining of digestive tract, respiratory b. endoderm: inner-layer- lining of digestive tract, respiratory system, urinary system, urinary

bladder, digestive organs such as liver, and many other glands. bladder, digestive organs such as liver, and many other glands. c. Mesoderm: Separates inner and outer layer- Most of the c. Mesoderm: Separates inner and outer layer- Most of the

skeleton, skeleton, muslcles, circulatory system, reproductive organs, and excretory muslcles, circulatory system, reproductive organs, and excretory

organs. organs. 8. atoms, molecules, cells, tissues, organs, organ systems, organism8. atoms, molecules, cells, tissues, organs, organ systems, organism

Body SymmetryBody SymmetryA.A. Three types of symmetry: body shapeThree types of symmetry: body shape

1. 1. Asymetrical:Asymetrical: no specific shape/irregular no specific shape/irregular

(Sponges, coral) (Sponges, coral)

2. 2. Radial symmetry:Radial symmetry: body parts are arranged around a body parts are arranged around a central axis, like spokes around a bicycle wheel. (Phylums central axis, like spokes around a bicycle wheel. (Phylums

Cnidarian, Echinodermata)Cnidarian, Echinodermata) These organisms resemble a pie where several cutting planes produce roughly identical pieces. An organism with radial symmetry exhibits no left or right sides.

3.3. Bilateral symmetryBilateral symmetry

a. Have distinct right and left halves. A plane passing a. Have distinct right and left halves. A plane passing through the animal’s midline divides the animal into through the animal’s midline divides the animal into

mirror image halvesmirror image halves. .

The elaborate patterns on the wings of butterflies are one example of biological symmetry.

Dissection/Position Dissection/Position TermsTerms

Dorsal: The back of an organismDorsal: The back of an organism

Ventral: Stomach areaVentral: Stomach area

Medial: middleMedial: middle

Lateral: SideLateral: Side

Anterior: Towards the head Anterior: Towards the head

Posterior: Towards the back end or rear end areaPosterior: Towards the back end or rear end area

Caudal: tail Caudal: tail

Cranial: HeadCranial: Head

Lateral

Posterior: hind end

Anterior: front end

Medial