The Kingdom Animalia: Unifying Characteristics and Major Divisions
Unifying Characteristics
• Haploid Gametes• Embryonic Blastula Development• Diploid Somatic Cells • Multicellular Lacking Cell Walls• Mitochondrial Eukaryotes• Heterotrophic• Aerobic Respiring
Haploid Gametes
• In animals the adults produce haploid (having half the number of chromosomes) gametes through meiosis
The Embryonic Blastula
• After fertilization of an egg by sperm, the resulting diploid (having two pairs of chromosomes) zygote rapidly goes through mitosis
• All animals become a hollow sphere of cells called a blastula
Mitochondrial Eukaryotes
• Cells contain Mitochondria inside cells that carry on Cellular Respiration
• O2 + Glucose CO2 + H2O + ATP
Heterotrophic and Aerobic Respiring
• In order to acquire the Glucose necessary for cellular respiration animals must be consumers and eat organisms already containing glucose
• In order to acquire the Oxygen gas necessary for cellular respiration animals must have mechanisms of obtaining oxygen
Major Divisions
• Symmetry, Movement, & Cephalization
• Gastrulation & Gut Formation• Dermal Tissues & Coelome
Development• Segmentation
Radial Symmetry
• Body plan in which the body parts are arranged regularly around a central axis (multiple planes cut into mirror halves)
Bilateral Symmetry
• Body plan in which body parts are arranged into a left and right around a central plane (one plane cuts into mirror images)
• Cephalization results from this plan
Gastrulation & The Gut
• After the blastula stage, in some animals cells migrate to the interior forming the primitive gut
• In Protostomes the initial pore forms the mouth, while in the Deuterostomes this pore forms the anus
Tissue Organization: None
• Parazoan animals have specialized cells but lack the tissue level of organization
Diploblastic Tissues
• Tissue organization first appears in animals like jellyfish which are Diploblastic (having a distinct Ectoderm and Endoderm)
Coelome Development:Acoelomate
• The coelome is a fluid filled cavity surrounded by mesodermal tissue
• Acoelomate animals lack a fluid filled cavity and are Triploblastic
Pseudocoelomate
• Pseudocoelomate animals have a fluid filled cavity but it is not contained within mesoderm tissue. Instead it lies between the mesoderm and endoderm
• Pseudocoelomates are Triploblastic (having an Ectoderm, Endoderm, and Mesoderm)
Eucoelomate
• Eucoelomate animals have a true fluid filled cavity contained with in the mesoderm
• Eucoelomates are also Triploblastic
Segmentation
• Segmented organisms have a repeating series of body units that may or may not be similar to one another