ShareOffspring Traits - I Feel Sick, and You Don't?
A Trip to Africa
You
have just arrived in Ghana, on the west coast of Africa. You step off
the plane and a swarm of mosquitoes surrounds you. Before you get in your
cab to go to your hotel, you notice at least five mosquito bites starting
to itch on your arm. You don’t think much about it--after all, you’ve
had hundreds of mosquitoes bites before. You’re not going to let
a few bites keep you from seeing the elephants and wild boars, after all.
About ten days later, though, you wake up feeling AWFUL! You have a headache,
a high fever, and you feel sick to your stomach. Your African guide takes
you to a local clinic where a blood test is done. Diagnosis? MALARIA.
Malaria is a disease carried by mosquitoes in some parts of Africa. These
mosquitoes have a tiny parasite in their saliva. When the mosquito bites
a human, it injects some saliva into the blood--and along with it comes
the parasite. These parasites invade your red blood cells and multiply
inside them. The red blood cells burst and die--sending more parasites
into your blood. This happens over and over, making you very sick! Some
of the symptoms are vomiting, diarrhea, and headache, to name a few. If
left untreated, it could kill you.
Your guide is sorry to see you so sick. After taking the medication the
doctor prescribed you start to feel better, and after a week or so, you
are almost back to normal. “Have you had malaria?” you ask your
guide. He smiles, and explains: “I have sickle-cell anemia. Malaria
does not make me sick.”
Why would this be?
A normal red blood cell (like what is found in your body) looks similar
to this:
In a person with sickle-cell anemia, such as your guide, some of the red
blood cells look like this:
It is common that people who have sickle-cell anemia are more resistant
to the malaria parasite.
Answer the following questions:
1. How does having sickle-cell anemia increase your chance of survival
if you live in Ghana?
2. Is there an advantage to having sickle-cell anemia if you live in the
U. S.? Why?
Now, how does this apply to other organisms? Let's look
at specific traits which may help an organism survive in the location
where it lives.
Seagulls are adapted to a life near the shore with webbed feet and a life in the air with wings and feathers to help them fly.
Organisms can have many traits which are qualities or features of an organism. The traits can be either inherited or acquired. When animals inherit traits, they sometimes are very helpful in survival. Sometimes the traits they inherit aren’t useful. Sometimes they actually prevent the animal from surviving at all. Over a long period of time the traits of a group of organisms in an area become more and more beneficial to their survival in that specific area.
Animals
that live in deserts usually have some common traits regardless of what
desert they live in. They all get by on very little water. They prefer
being active when the temperature is the coolest (usually around dusk
and just after dawn.) In the same way animals that live in cold climates
have similar adaptations. They may be active only during the middle of
the day when the temperature is warmest. They may have thicker fur or
more feathers than similar animals that live in warmer areas. Plants have
the same tendency to have traits adpated to a specific environment. Cactus
plants have a thick waxy skin to prevent the loss of water.
Traits of an organism aren’t much good to anyone but that
organism unless that organism can give those traits to someone else. Reproduction
is all about giving traits to someone else. When an organism reproduces,
it passes its traits on to its offspring. Animals that reproduce sexually
can combine traits from different animals and sometimes the combinations
are better than either parent but sometimes they are worse. Imagine your
lawn. Every spring you go out and mow it. You may have noticed some dandelions.
If you never spray for dandelions, will they survive? Some will. Which
ones? You may have predicted “The short ones.” The short ones
may have advantage in your lawn since you cut it with a lawnmower. The
only flowers that would survive to reproduce would be the ones who are
too short to be cut by the lawnmower. In another environment maybe only
the tall ones survive. They may be better able to get sunlight or water
or some other requirement for life. All organisms function this way.
You may have heard the phrase: "survival of the fittest" before.
It brings up images of big strong capable organisms struggling to beat
each other out for food. It can sometimes be that, but fittest doesn’t
mean the most physically fit, rather it means the organism that “fits”
best in its environment. As stated above in the section on reproduction,
the organisms that have the traits that best suit them for survival are
the organisms that will reproduce. Organisms that don’t “fit”
in their environment don’t always die immediately but often they
don’t reproduce or don’t reproduce as often or as well and
so they have less offspring. On the other hand organisms that are more
fit for their environment often have more offspring. Traits then that
help an organism survive become more and more common and traits that aren’t
useful become less and less common.
Analysis:
You are to use the knowledge you have about how traits help organisms
survive. In doing this, you will create a children's story to explain
this information.
Here is an example of a children's story that is related to this topic. Once upon a time in the Amazon basin in Brazil a there lived a parrot named Pauline. Thousands of miles away in Anarctica there lived a penquin named Peter. Pauline didn’t like living in the Amazon anymore. She was tired of the heat, all the green and always looking like all of the other parrots. Peter felt the same way. He was tired of the cold, all the white and always looking like all of the other penquins. The both got onto "wildnet," the animal Internet. They started searching for a new place to live. The two birds posted their own homes for sale and then found each other's homes and so before you can say, "feather" they had switched homes....
What a great story right? Well now it is your turn. Animals have different traits that they have inherited to help them survive in their environments. Parrots are brightly colored which makes it easy to find each other in a dark rainforest. Penquins are black on top and white on bottom which makes it difficult to see them when they are swimming through the water. They both have other traits that help them in their natural environment. What would happen if they really did move. You will be writing and illustrating a children’s book about that possible situation.
Your children's story needs to include certain things. Use the following list to plan your story.
- Cover (Front and Back)
- Pages
- Organism and 2 Environment Traits of your organism
- Advantages for natural environment
- Disadvantages for new environment
- Illustrations
- Text
- Overall Quality
You should do your planning on something called a story board (a rough draft of your story.) To create a storyboard, take a regular piece of white paper and fold in half three times to make eight frames.
In each of these frames plan a page of your children’s
story. Include the type of illustration, text you may use and other
elements. This storyboard is like a rough draft. It will help you to
organize your final story. Use it to plan for all of the things in the
above chart.
You may need to go to the library, use the Internet or an encyclopedia
to research an organism you are interested in and and the two environments.
Use the information you gain to design your story.
