Beyond Football - Freestyle Football Forum
General Category => General Chat => Topic started by: Jono on Feb 17, 2008, 07:31: PM
-
Aiight if you have any questions on these science topics, smarter members please help
I need some help myself in biology. What Darwins 5 main steps of evolution? Ive tried lookin but i always get long answers, are there any shorter ones you guys can give me.
-
I did this recently but kinda forgot...
its erm...
this isnt that long or complicated,
"
Whilst studying wildlife on the Galapagos Islands he noticed that the Galapagos finches showed wide variations - eg in beak shape and size - from island to island. Darwin deduced that these differences made the finches better adapted to take advantage of the food in their particular local environment - thin, sharp beaks prevailing where the birds' main food was insects and grubs, and large claw-shaped beaks where their diet was buds, fruit and nuts. In each locality the finch population had somehow developed beaks which were suitable for that particular environment.
Darwin concluded that in each locality one or more individual finch happened to acquire, by random mutation, a beak shape more suitable for the food sources in that locality. These individuals then had a competitive advantage over their fellow finches, enabling them to grow and reproduce more successfully, and pass on their more specialised beaks to successive generations - until eventually the characteristic had spread throughout the finch population in that locality.
He studied hundreds more animal and plant species, and made the following key observations:
* That living things tend to produce far more offspring than will survive to maturity
* That within a species population numbers tend to stay more or less constant over time
* That each species displays a wide variation in features
* That some of these variations are passed on to the next generation
Darwin's theory explained these key facts. He inferred that living things are in continuous competition with each other - for access to space, food, and mates, for example - and that only the best suited, or 'fittest' survive to reproduce and pass on their genes. Any characteristic acquired by chance mutation that gives an individual an advantage in the struggle will be naturally selected for.
Natural selection means the survival of organisms that are best suited to surviving and reproducing in their environment. Over millions of years, this process produces not just variations within species, but entirely new species as well. It is the engine of evolution.
"
The weaker animals become extinct, those that mutate survive and breed more offspring which also survive, this is natural selection
-
Use a search engine holmes. What the fuck are all these topics like this doing here. I don't get paid to help you with your homework.
-
I did this recently but kinda forgot...
its erm...
this isnt that long or complicated,
"
Whilst studying wildlife on the Galapagos Islands he noticed that the Galapagos finches showed wide variations - eg in beak shape and size - from island to island. Darwin deduced that these differences made the finches better adapted to take advantage of the food in their particular local environment - thin, sharp beaks prevailing where the birds' main food was insects and grubs, and large claw-shaped beaks where their diet was buds, fruit and nuts. In each locality the finch population had somehow developed beaks which were suitable for that particular environment.
Darwin concluded that in each locality one or more individual finch happened to acquire, by random mutation, a beak shape more suitable for the food sources in that locality. These individuals then had a competitive advantage over their fellow finches, enabling them to grow and reproduce more successfully, and pass on their more specialised beaks to successive generations - until eventually the characteristic had spread throughout the finch population in that locality.
He studied hundreds more animal and plant species, and made the following key observations:
* That living things tend to produce far more offspring than will survive to maturity
* That within a species population numbers tend to stay more or less constant over time
* That each species displays a wide variation in features
* That some of these variations are passed on to the next generation
Darwin's theory explained these key facts. He inferred that living things are in continuous competition with each other - for access to space, food, and mates, for example - and that only the best suited, or 'fittest' survive to reproduce and pass on their genes. Any characteristic acquired by chance mutation that gives an individual an advantage in the struggle will be naturally selected for.
Natural selection means the survival of organisms that are best suited to surviving and reproducing in their environment. Over millions of years, this process produces not just variations within species, but entirely new species as well. It is the engine of evolution.
"
The weaker animals become extinct, those that mutate survive and breed more offspring which also survive, this is natural selection
Did you do this in school now? you must be about year 10. I was doing this exact same thing in year 12 right before my last exam lol.
-
Lol, yeah I'm year 10
-
lol melbourne same here, im doing it now in year 12
i got another question
im suppose to be writing about a case study on how enviromental changes can lead to a change in a species
the one im doing is DDT on mosquitoes, now i get how the use of DDT killed many mosquitoes and few were imune then later produced offspring that were also imune, but i dont get how DDT is a environmental change. Someone can help with this
And thanks finnery
-
http://wordnet.princeton.edu/perl/webwn?o2=&o0=1&o7=&o5=&o1=1&o6=&o4=&o3=&s=environment&i=0&h=00#c
-
I dont want to know the defination of environment, i want to know how the use of DDT to kill mosquitoes is a enviromental change
-
"the totality of surrounding conditions"
A change in the environment could include the introduction of a foreign substance into the organism's immediate surroundings.
You're thinking environment restricted to green shit.
-
ahhhk thanks
so basically the environmental change off DDT being introduced in the environment, decreased the amount of mosquitoes dramatically... etc
-
i have those subjects too, but i think im too late because finnery already helped you ;)
-
we did the DDT in year 8 or something I think, quite fascinating how the education and curriculum is so different throughout countries. but it seems your DDT question is answered anyway :)
-
I got a chemistry question for any of you who does chemistry as a subject. Ive tried checkin up on google, but no luck.
Anyways the question is; Why is it important to exclude air in catalytic and thermal cracking?
I have an idea, but i am not sure.
-
i have chemistry but i think you are further than me, because i really dont understand
-
i have chemistry but i think you are further than me, because i really dont understand
lol I hate all science...I knew some of this stuff, but even writing an answer would be pain. I am dropping it as soon as possible and taking English a year ahead :thumbsup:
-
Anyways the question is; Why is it important to exclude air in catalytic and thermal cracking?
To avoid undesirable chemical reactions
I don't know how in depth you have to go, but that's where I'd start.
-
Can you go abit further into depth with it, imagine it is worth around 3-4 marks
-
I don't know really know what you're expected to know, but
You want alkenes. In cracking hydrocarbons, you break down alkanes (no c-c multiple bonds, more stable) to get alkenes (c-c multiple bonds, less stable). Without air, you avoid things like combustion which yields CH4 + 2O2 = 2H2O + CO2 (useless).
-
ahh yeah i get it, bease alkanes react with air to form carbon dioxide and water, therefor you wouldnt be getting the alkenes you want....
thanks heaps :thumbsup:
-
Well not just that, but other things. Basically, things in air react to form other things that you don't want (is what I'd put).
http://en.wikipedia.org/wiki/Pyrolysis
That's very similar to cracking. You should be able to find things that would relate to air in cracking.
-
thanks heaps a;sdlfkjas;df :thumbsup:
-
Hey how do i work o ut the number of monomers in a polymer?
The actual question is:
A sample of PVC has an average molecular wieght of 7.2 x 10^4; what is the average number of monomer units in a molecule of this sample?
I dont get it, please explain.
-
Start here: http://en.wikipedia.org/wiki/Vinyl_chloride . Pay attention to g/mol.
-
I cant find my answer anywhere, it doesnt talk about how to work out the number of monomers in a polymer etc, unless i read over it somewhere
-
A mole of the PVC monomer Vinyl Chloride weighs 62.498 grams. 6.02214199 x 10^23 monomers per 62.498 grams of Vinyl Chloride.
-
Can someone please explain polar and non polar substances, but please dont give me a wikipedia link. Explain it so its easy to understand.
Thanks
-
Polar substances have partial charges. Nonpolar substances do not.
-
Can you be abit more specific, like give an example.
What do you mean by partial charges?
-
H2O is a polar molecule. Partial charges: one portion of the molecule has a net negative charge (O); one portion of the molecule has a net positive charge (2 H atoms).
-
So non polar will have the same charges. Does this make all elements non-polar?
-
No, molecular structure factors in as well, e.g. ozone is polar.