kingdom Animalia Flashcards
kingdom Animalia is divided into 2 major groups
an animal is a multicellular, eukaryotic heterotroph whose cells lack a cell wall. a) invertebrates, b) vertebrates
invertebrates
animals without a spine: 97% of all animals
vertebrates
animals with a backbone: 3% of all animals
general characteristics of an animal
- heterotrophic and usually obtain food through ingestion followed by digestion
- typically can move by way of muscle fibres
- multicellular, with specialized cells
- typically a diploid adult stage in life cycle
- usually has sexual reproduction and produces an embryo that undergoes developmental stages
evolution of animals
more than 30 phyla are believed to have evolved from a Protistan ancestor. difficult to trace because many animals are soft-bodied and do not leave fossils
taxonomists use 4 criteria to classify animals
level of organization, body plan, type of symmetry, and type of coelom
level of organization
cell, tissue- a group of similar cells
organ- different types of issue grouped together
body plan
the sac plan
the tube-within-a tube plan
type of symmetry
bilateral, radical symmetry, asymmetrical, spherical
type of coelom
a coelom is a body cavity, acoelomate, psendocoelom, true coelom
bilateral
definite right and left halves
radical symmetry
symmetry around a central axis
asymmetrical
no particular symmetry
spherical
two identical halves no matter how the animal is divided longitudinally
type of coelom- mesodermal tissue
forms mesentery which holds internal organs in place
