Biology Mr. Willets
Animal Kingdom- Part 3
VERTEBRATE SYSTEMS- In vertebrates, there a 11 systems that perform all the functions needed for the survival of the animal. Many of them have been described previously, some have been ignored. The first letters from these 11 names can be arranged in a way to help you to remember them.
Skeletal, Circulatory, Integumentary, Respiratory, Excretory, Muscular, Immune, Nervous, Digestive , Endocrine, Reproductive
(integumentary- outer protective layers- skin, hair, nails,
scales, feathers etc.)
(endocrine- system of glands that produce hormones to regulate body
activities)
PARASITIC WAY OF LIFE- Parasites live their lives quite differently compared to the free-living animals. As a result, the body of a parasite is often adapted for their unique life style.
A) some systems in parasites are not needed or needed less than in
free-living animals. In these cases, the systems are missing or less
developed- This is called degenerative evolution. Examples
1) digestive system- many parasites live in the host's intestines
where the food is already digested
2) nervous system- since they live in their food and the environment
rarely changes, there is not much need for this system
3) muscular-not much need to move when you live in your food and
environment doesn't change.
B) parasites often need protection against being digested by the host's intestine.
C) parasites often have a method of attaching to the host - hooks and/or suckers are common.
D) the offspring of parasites must leave the host to prevent overcrowding. Too many parasites in one host might kill the host and with it, the parasites.
1) for intestinal parasites, eggs leave in host's feces -these then could contaminate food and water. Sanitary disposal of wastes prevents the spread of these parasites.
2) insect vectors- the offspring must be in the blood of the host. Killing the insects can slow this method of spreading.
E) parasite's offspring need a method of entering a new host
1) contaminated food and water-host eats the parasite. Prevention includes inspecting food and water
2) insect vector- once again, killing the insects can help slow the spread of the parasite.
3) the parasite larva bores through host's skin- on land, it usually bores in through bare feet. In water, it can bore in most anywhere on the body. This is rarely noticed when it happens.
F) parasite offspring needs protection when in the environment and not yet in a new host.
1) some form protective cysts- often the new host eats food contaminated with these cysts.
2) some enter a secondary host and reproduce asexually to increase the number of offspring. More offspring increases the chances that some will make it to a new host.
G) since most of the parasites' offspring do not find a new host and therefor die, the parasite produces large numbers of offspring. As a result, most parasites have a large reproductive system.
Biology - Mr. Willets
Animals-Part 3 Questions
1) How many systems are there in the vertebrate body? ________
2) Without looking on the other side, how many can you name using SCI REMINDER? __________
(eventually, you had better be able to name them all)
3) Why might a parasite not need a digestive system? _______________________________________
What problem would a parasite encounter living there? ______________________________________
4) The loss or down-sizing of certain systems in parasites is called ____________________ evolution.
5) If an intestinal parasite did not have hooks or suckers, what might happen to it?
______________________________________________________________
6) What could happen if all of the offspring of a parasite remained in the same host? _________________
How could this affect the host?____________________________ What would then happen to the parasites?______________________
7) The eggs or larva of an intestinal parasite can easily leave the host in the host's _________________
Are you worried about this in this country?_______ Why not? ________________________________
___________________________________________________
8) Insect vectors can spread parasites only if the offspring of the parasite are located in the ____________ of the host.
9) In certain parts of the world, it is a good idea not to walk around in bare feet. Why? _______________
____________________________________________________________________________
10) To protect themselves while in the environment, some parasites form _______________.
11) When a parasite enters a host other than its main host, it does so for protection and to __________________________________. This produces more parasites and increases the chances that more of them will find a new ____________.
12) A host other than the main host is called the _______________________ host.
13) What happens to most of the offspring of parasites? ____________________________________
14) Let's say the chances of survival and finding a new host are way less than 1%. If a parasite produced 100 offspring, how many would survive to carry on the line?(not an actual number here- just the idea) ____________________________________ What does the parasite do to avoid this problem?
___________________________________________