PiratMas17875

There's a small problem with your question: Gravity. Gravity determines how large certain creatures of this planet can get, that's why we don't see man-sized insects (in addition to the Oxygen thing). An ant's own body weight would crush it under normal earth gravity and pressure.
I do, however, want one of those teacup giraffes.

As every woman who has ever lied to a man knows, size really does matter. And it is true in the animal kingdom as well. Life expectancy is linked directly to the speed the heart beats at and generally speaking smaller animal’s hearts beat more quickly. No matter what the species we all of us have roughly the same number of heart beats we can use in a lifetime and if your heart beats quickly then you move quickly and time appears to move more slowly for you. There are some exceptions to this general rule about size and heart rate though, a very large dog like a Great Dane has a life expectancy of about ten to twelve years, but a very small dog like a Terrier can live fifteen or sixteen years.

 
Unlike big cats like lions and tigers, our cat’s (All housecats are descended from as few as five female African cats 8000 BCE) have been domesticated over a period of thousands of years. So even if they were enlarged to be the size of other big cats they would still be able to be domesticated. We see the same thing with dogs and wolves. Thousands of years of living with man has forever changed the behaviour of dogs, wolves however are naturally much wilder. Just like with dogs though, if cats were large enough to kill us they would occasionally do so and probably much more frequently than dogs do.
Insects are limited in how large they can grow because of the way they absorb and distribute Oxygen through their bodies. The largest insect that ever lived was a type of dragon fly that was thirty inches long and weighed over 1lb but this insect lived about 300 million years ago when Oxygen levels were higher than they are today.

this guy is my hero

I believe it would be complete chaos If Insects like Mosquito's were bigger we would be in for Damnation for sure the way them buggers like to suck blood from anything living, well hell they could drop humans in just one feeding and if the blood they drink has anything to do with making them live any longer, afew humans and they would be Immortal insects, the end of mankind for sure:)~

i don't think so

Whoa...that question stopped me for a second there. I think it all comes down to how much bigger the animal/insect gets. If ants become the size of lions for example then they would probably rule the world. I know brain size is not directly proportional to intelligence but it leaves room for more evolution. Besides, imagine that an ant can lift 10x its own weight. Imagine what it could lift if it weighs around 100 kilos. Scary thought. Also, I don't think size is really a major factor in an animals/insects life expectancy. I think it all comes down to how the organism is evolved and how it operates. Humans can only live to about 150 years in the most optimal circumstances. Some species of turtles can live for over 200 years, same goes for some species of birds. There are so many factors involved here that a single 5 paragraph essay alone won't be enough to explain. I don't know if there are any papers out there with this topic but I'm not interested in writing one. Too bad I failed biology...ow well...back to school I guess.

Very interesting question.i always wonder what it must have been like to live in prehistoric times,i think man would have had to be much tougher then than they are today.
Imagine been confronted by a huge creature towering over you !!
I think our lives would be shorter if we were bigger don't really know why ....
Tigers are beautiful creatures imagine how lovely it would be if we could have one as a house cat would be expensive to feed though !!

As a biologist I would say.... nothing. They are superb in every aspect.

Very interesting question and blog. This one has me stumped. I think it suggests a disruption in the food chain. Imagine a hawk flying dow to get a rat only to be eaten by the giant rodent. That's a game changer.