Animals Chapter 32
Characteristics of the Animal Kingdom 1) Multicellular 2) Heterotrophic 3) Sexual Reproduction and Development (Most reproduce sexually) 4) Movement – Most animals move around their environment 5) No cell walls 6) Eukaryotic
Multicellular Organization Bodies of all animals are multicellular (More than one cell) Each cell depends on the presence and functioning of other cells There is a division of labor among cells
Specialization Definition: the evolutionary adaptation of a cell for a particular function Each cell has its own function, but together they make an organism work Examples: Muscle Cell, Skin Cell, Heart Cell
Animal Organization Tissue- a group of cells that perform a common function Example: Muscle Tissue Organs- Body structures that are composed of more than one type of tissue and are specialized for a certain function Example: Heart Organ Systems- Many different organs that function together to complete the same task
Multicellular Organization Multicellularity and Specialization have enabled organisms to evolve and adapt to many environments Why do you think it is more difficult for unicellular organism to adapt to many environments?
Heterotrophy All animals are Heterotrophs - they must obtain complex organic molecules from other sources Ingestion-an animal takes in organic food, usually in the form of other living things Digestion-Organic molecules are extracted from the material or cells the animal has taken in.
Sexual Reproduction and Development Most animals reproduce sexually – Two haploid cells (gametes) form a diploid cell (Zygote). Development – Cells keep dividing by Mitosis and cells undergo Differentiation Differentiation- Cells become specialized
Movement Most animals move around their environment Movement can only occur because of the relationship between the nervous tissue and the muscle tissue Nervous System- allows you to detect stimuli in its environment and within its own body Muscular System – Can contract and exert force to move specific parts of the animals body