Question

Compare animals:

• earthworm
• clam
• grasshopper
• fish
• frog

and research the anatomy of these body systems:

• digestive
• nervous
• respiratory
• cardiovascular
• excretory/osmoregulatory

1. Identify 2-3 similar anatomical structures that appear in all the animals for which there were posts. Why do you think these structures have remained similar even though these animals are from different phyla?

2. Which of these animals live on land and which live in the water? Discuss which anatomical features are specifically adapted to each environment.

3. Animals need to exchange molecules with the environment to support their metabolic rate and we see that they often optimize this by increasing surface area. Where specifically do you see the maximization of surface area among these organisms?

Answer 1

	Earthworm	frog	clam	Grasshopper	fish
Digestive system	The Digestive system consists of the pharynx, the esophagus, the crop , the intestine and the gizzard (stomach)	frog has more well defined digestive sysytem than an earthworm, it has the esophagus, stomach, duodenum, liver, pancreas, gall bladder and the intestines.	consists of mouth,esophagus, a stomach and an intestine	It has the mouth, the esophagus, the crop, the gizzard ,gut , the gastric ceca and the anuss	It includes mouth, teeth,esophagus, stomach, pancreatic tissues, liver, gall bladder ,intestine and anuss. This are the commonly found components not all fishes do have all components.
Nervous	The central nervous system consists of a bilobed brain, sub pharyngeal ganglia, circum-pharyngeal connectives and a ventral nerve cord	differentiated into 4 brain vesicles and spinal cord	Nervous system consist of 3 pairs of ganglia connected by nerve cords and the nerve connect the nerve cord and ganglia to sensory cells	It has a brain connected to the 1st ventral ganglion by a pair of ventral nerves	It consists of a brain, spinal cord and nerves
Respiratory	Earthwoems donot have lungs and the exchange of gases ( oxygen and carbondioxide) directly takes place through moist skin of erthworm through diffusion.	even though frogs do have functional lungs they mostly breathe through their skin, the moisture on the skin dissolves oxygen from air or water in the surrounding and transmits into the blood	Clams have gills for breathing like most aquatin species	Exchange of oxygen and carbondioxde takes place through tracheae, which are open to the outside through small holescalled spiracles	Gills are the organs through which a fish breath in water, the oygen in water is absorbed by the blood anf the carbondioxide is released outside
cardiovascular	An earthworm have a heart like structure called the aortic arch, which are 5 in number, they are responsible for the supply of blood throughout the body and they do this with help of dorsal blood vessels and ventral blood vessels .	The heart of a frog has 3 chambers, blood and blood vessels,	Have open circulatory system, they do have a 3 chambered heart, blood, and blood vessels	Open circulatory system, consisyting of blood, blood vessels, and the hemolymph (heart)	consist of heart which have 2 chambers,blood and blood vessels
excretory/ osmoregulatory	The excretion of gases ( carbondioxide) is done through moist skin and the nitrogeneous waste filtered by the nephridia (kidney like structure) is excreted out of the body through anuss	excretory system consists of a kidney pair, a pair of urters, a urinary bladder and a cloaca, here the kidneys filtere the waste from the body and removes the urine (waste) out through the cloaca.	They do have a kidney like body part called nephidia, bladder and a siphon (to excrete out waste products.	Malphigian tubules are the excretory organ of a grasshopper	Fish uses their gills or urinary pore to urinate or remove wastes, kidneys are also present and used for filtering out the waste.
Ans2) lives on land or water	Earthworms lives on land in the soils and are adapted to thier surroundings by having moist skins for the difusion of gases and waste .	Frogs are amphibians , that is they live both of land and water and thus they are adapted to both terestial and aquatic surrounding by developing lungs for land and moist skins in water for breathing .	clams are aquatic beings , they live in water and are having gills to breath in water	grasshopper lives on land and have trachea ( lungs substitute) to breath on land	Fish lives in water and adapted to it by having gills to breathe in water etc

Ans 3) We can see maximization of surface area in case of earthwormsz and earthworms body is segmented and folded so that maximum surface area is utilised, since the earthworm do require its moist skin for breathing and excreation purpose. Even a frog so utilize its skin surface area for breathing or exreation purpose but it does have other organs to do the same tasks. The more an organism have a complex system the more well defined structure it does have