Topic 19: Introduction to Animals Flashcards
Definition of an Animal
Multicellular, heterotrophic eukaryotes with tissues that originates from embryonic layers.
Animal Cell Structure
Multicellular, lack cell walls (has collagen instead), differentiate into specialized types.
Nutritional Mode
Chemoheterotrophs
Sexual Reproduction
Meiosis producing haploid gametes that fuse during fertilization to form a diploid zygote. Diploid stage dominates life cycle.
Asexual Reproduction Types
Through Fission/fragmentation, Budding, and Parthenogenesis.
Embryonic Development Steps
- Cleavage
- Blastulation
- Gastrulation
Cleavage
Rapid mitotic divisions making a morula.
Blastulation
Continued cleavage creating a hollow blastula.
Gastrulation
Forming a gastrula within different layers of embryonic tissues.
Blastocoel
Fluid filled cavity in blastula
Hox Gene
Determines the body plan and segment identity during embryonic development.
Ectoderm
Outer layer of the Gastrula, becomes the skin and nervous system.
Endoderm
Inner layer of the Gastrula, lines the digestive tube.
Archenteron
Cavity inside gastrula.
Blastospore
The opening of the archenteron.
Radial Symmetry
Their body is arranged around a single main axis that passes through the centre, associated with the digestive track. (Often fixed or weak moving)
Bilateral Symmetry
Most animals, distinct left and right side w/ a single line along a head-tail axis.
Cephalization
Development of head region containing sensory organs.
Tissues
Specialized cells with functions.
Diploblastic
Two embryo layers, radially symmetric.
Triploblastic
Additional in between layer - mesoderm - which becomes the muscles and organs, bilaterally symmetrical.
Coelom
Develop in larger animals, forms from the mesoderm, contains, coelomic fluid, connects and suspends internal organs.
Hemocoel
Between mesoderm and endoderm, arises from the blastocoel, contains hemolyph fluid.
Hemolymph Fluid
Acts as an open circulatory system.
