Classifying Animals Flashcards
The 3 types of symmetry in animals
bilateral
radial
spherical
Definition of symmetry and asymmetry
S- body parts around central plane or axis
A- body can’t be divided into sections (sponges)
Definition of radial symmetry
body parts arranged around central point like spokes on a wheel
echinoderms
most are sessile or sendentary
Definition of bilateral symmetry
can be divided into equal halves along single plane
usually motile
Bilateral Symmetry: what type of images do they portray?
mirror images
When does segmentation occur?
When animal bodies are divided into repeating units/segments
Where is segmentation normally found?
in more complex animals
What type of segmentation do humans have?
internal
What type of segmentation do earthworms have?
external
The levels of organization
atom - molecule - organelle - cell - tissue - organ - organ system - organism
All organisms except for sponges show these levels….
cell, tissue, organ, organ system
Traditional Classification name
metazoans
Parazoa and Eumetazoa
P- lack symmetry and tissues
E- have symmetry and tissues
Diploblastic and Triploblastic
D- have 2 germ layers
T- have 3 germ layers
Animal classification is constantly ______.
changing
