PLANTS AND ANIMALS. II 
animal the demands of locomotion and alimentation are 
best satished by a maximum bulk with minimum surface, 
whereas In a plant the absorptive area, being mainly co- 
extensive with the surface, the typical plant tends to attain 
minimum bulk with maximum surface. With such a large 
Proportion of surface there is no necessity for excretory 
organs. 
Lastly, from the difference in food it follows that a plant 
can, from the simplest to the highest, protect its body in 
a supporting membrane, usually of cellulose, whereas an 
animal must always have a certain part of its surface 
exposed to form an ingestive and egestive area. When, as 
in low types. the ingestive area is co-extensive with the 
surface (¢f Ameba), the difference in this respect from a 
plant is very marked. We may tabulate these differences 
as follows :— 
PLANT.* 
. Protoplasm has chlorophyll. 
- Food liquid or gaseous. 
. No alimentary organs nor 
excretory ; motor and sen- 
sory organs little developed. 
. Form tending to maximum 
surface with minimum bulk. 
. Body completely clothed in 
coat (cellulose). 
. Are dependent on salts, car- 
bonic acid gas, water and 
sunlight. ‘ 
ANIMAL.#* 
- No chlorophyll. 
. Food solid, and mostly in- 
soluble. 
. Alimentary and_ excretory ; 
motor and sensory organs 
highly developed. 
. Form tending to maximum 
bulk with minimum surface. 
. Body naked in lowest types, 
partially enveloped in exo- 
skeleton in higher. 
. Live only upon plants or 
other animals (highly or- 
ganised food), and do not . 
require sunlight or carbonic 
acid. 
The plant-nutrition is sometimes termed holophytic and animal- 
nutrition is then known as hodozoic. 
Transfer of Energy.—The movements of animals, 
and the maintenance of a high temperature in the higher 
* Fungi form an exception to 1 and 6 in the ‘‘P/ant” column, 
whilst Hydra and a few other animals form an exception to I in the 
“Animal” column. One or two plants are partial exceptions to 3. 
