introduction to animals chapter 34. what makes an animal an animal? multicellular heterotrophy ...
TRANSCRIPT
Introduction to AnimalsChapter 34
What makes ananimal an animal?
Multicellular
Heterotrophy
Sexual reproduction & development
Movement
Body Symmetry
Radial symmetry- a body plan in which the parts are organized in circle around an axis.
Body Symmetry
Bilateral symmetry- two similar halves on either side of a central plane
Body Symmetry
Asymmetry- no organization
Body Cavity
Body cavity- fluid filled space that forms between the digestive tract and the outer wall of the body.
Aids in movement and acts as a reservoir and medium of transport for nutrients and wastes.
Animal Kingdom
Invertebrates Animals without a Backbone
or Spinal Column
Vertebrates Animals with a Backbone or
Spinal Column:(All these animals are in the phyla Chordata and the subphyla Vertebrata.)
Vertebrates
Vertebrates are a subphylum of chordates.
Chordates comes from notochord which is a firm, flexible rod of tissue located in the dorsal part of the body.
In vertebrates the notochord develops into a brain and spinal cord.
Invertebrates
Most invertebrates have bilateral symmetry which is an adaptation to a more motile lifestyle. It allows for cephalization.
Radial symmetry are not very motile and drift along, allows for more access to food sources.
Cell to Embryo•Cleavage- the series of cell divisions that occurs immediately following fertilization
•Blastula- dividing cells become a hollow ball
•Gastrulation- transforms the blastula into a multilaytered embryo called the gastrula
Germ Layers
Ectoderm- outer layer of the gastrula Forms the outer layer of skin, hair, nails and the
nervous system
Mesoderm- middle layer Forms the skeleton, muscles, inner layer of skin,
circulatory system and the lining of the body cavity
Endoderm- inner layer Forms the urinary and reproductive systems, and the
digestive tract; pancreas, liver, lungs and gills