-LIFE ON EARTH-
Ohkay, this is a 2 day lecture my biology teacher gave us on WHO LIVES ON PLANET EARTH. Its about 20 chapters long, so obviously we wont get the complete awsome story of biology.
To start the spectacular world of
PROTISTS. =)
First of all, what's a protist?
well a protist is a one celled living creature. YES. living. it is not a human, it is not a plant, fungus or a animal.
So what does this one celled creature have in common with us?
-The same thing it has in common with every single celled living thing on earth. it Eats- processes- synthesizes- eliminates. or EPSE
How does it achive all of that, with it being single celled?
-Because it lives in water! All cells NEED to be surrounded by water.
For example a sponge:
it is a living creature. It EPSEs. How because it is surrounded by water.
We evolved from water creatures.
& so our journey begins.
The evolution of our body systems.
the cnidarians, like hydras & corals where the first step to developing a digestive sack.
But now instead of just waiting for for the food to hit it BAM. it hunted. Although it still waited around.
It had a MOUTH. or just a simple opening in which it would suck in food.
this is where the first EXTRACELLULAR DIGESTION took place. Whats that you ask?
EXTRACELLUAR DIGESTION- is when digestion happens out side of the cells, in a stomach of some type.
From there it would just do its EPSE. But... Where would the waste go if there is no ANUS!?!?. well.. no other exit but the way it came in from.
Whats the next step?
You are now taking in bigger food, so you need to be able to synthesize it & extract everything from it right?
So you need compartization. & that takes us to WORMY. It has a tube within a tube, levels of complexity, so that different parts can digest different things.
So now we have a good Digestive System. What now?
How do we get from the oceans, & lakes to land?
- We need to have support.
--Sense organs
---& a breathing apparatus
important word CHORDATA. we belong to it, most animals belong to it to. What it mean? it means we have a BACKBONE.
Circulatory Systems
there are two types.
CLOSED- We have this type of system. It is closed (duh hints the name). But why is it closed? When it's closed,it helps the blood circulate faster, easier & it makes us WARM BLOODED! Our dirty blood does not mix with our clean blood.
OPEN- It is Open... lol. Well as a example, a grasshopper has this type of circulatory system. Blood is pumped multiple hearts. This isnt good because it guarantees a short life span because blood is just randomly distributed to the cells.
STOP! RETHINK!
Evolution does not just happen over night. A protist didnt just go BAM maybe i should have a heart. Evolution happens in small steps. And if one system is going to evolve,the rest will evolve too.
So obviously we need to change the OPEN CIRCULATORY system. but keep in mind that ALL , I mean ALL cells must be surrounded by H20. if not it dies. Just look at your skin!
Thats dead Cells all the way!
Your heart needs to change if you want to get any bigger, and there cannot be any mixture of blood.
What makes things go faster? MORE OXYGEN!
Amphibians- Ohkay so they have a 3 chambered heart. BUT. the dirty and clean blood mixes at the ventrical. So that is deffenitly a problem and needs to be re designed.
In your body, you have veins and arteries. We all know that arteries go away from the heart and veins go to the heart. But did you know that they had HOLES in them.
Which leads us to the next thing! Most people never hear of this, but is is MUY MUY IMPORTANTE.
The Lymphatic System
I bet you are going like what in the world is that?!?
Well dont feel bad i didnt know much about it either.
It is part of the circulatory system. It helps keep all you cells wet.
STOP!! RETHINK!!
remember how protists survived? b/c They were always kept moist! in water! H2O!
So, the lymphatic tissue oozes blood through your body, and it bathes all your cells. So that they stay surrounded by water at ALL times.
EXAMPLE: you know how when you sit down for a really really long time, all the blood goes to your feet, and they swell up? Well all your blood goes to your feet, thats when the lymphatic system goes to work. it starts oozing blood to keep your cells wet.
NON EXAMPLE: when your foot falls asleep. The weird tingly sensation you feel is not the LS, but the blood rushing back to your foot. (durrr )
SUMMARIZE IT FOR ME!
We need more O2 in our blood right, so we need a better heart, whats the better heart? A 4 chambered heart that can pump blood faster and better! & keep the bloods from getting combined. The lymphatic system keeps you alert and keeps your cells alive by covering them with blood!
