according to Charles Darwin, animal groups must struggle to survive because?
596690
The population tends to increase faster than the food supply.\n\nIn general, at least with humans, the population increases exponentially while the food supply increases linearly leading to shortage/hunger.
389820
The part of the body that are use more often, become more complex, in the same manner, part of the body that are less useful to survival will eventually be select against (It waste energy without generating enough benefit). Therefore mother nature tell us that, (Darwin's natural selection) we only have what we need. If we use this as an argument. We can assume that all animals today would use 100% of the brain, those who had use less than that would have been eliminated through the course of history. Unless it was beneficial to their survival, in that case, their brain will have "de-evolve" to maintain a lower energy consuming. The process of de-evolving would led them to use 100% of their brain...
30532
To become "selected against" the individual organism must die before it is able to reproduce. If it manages to reproduce, it will escape natural selection and perpetuate its DNA. Hence, not only the strongest survive. Only the very weakest and unfeasible of organisms die out.
1123043
Yes...however, the human race is one of the few species on the planet that kills one another for conflict not just for survival. In most cases when animals confront eachother it is very rare that one of the animals is killed, let alone seriously injured.
523965
D\n\nPoint C is a frequent misunderstanding of the principle of evolution. Animals do not evolve on purpose or to any particular goal. There was a long squabble about this early in the 20th century: see if you can find out anything about the Soviet biologist Lysenko. \n\nPoint A is due to Malthus. \n\nI don't recognise point B.
1005440
I would say C. The animals that died were weaker than the animals that survived. Their deaths might have occured because they did not possess the genes that enabled them to survive. The wildebeests that survived had adaptations that allowed them to better adapt to the environment.\n\nHowever, it could also be B. Perhaps the animals that died were just old and died of natural causes.\n\nIn my opinion, this question is poorly worded.
569367
Since they don't take care of their eggs, there is a greater probality that their eggs will be eaten up by predators etc and won't survive!\nThus they lay more eggs to ensure the continuity of their species.
1180368
Charles Darwin founded the theory of evolution.
983838
Darwin never "withdrew" his theory, nice try.\n\nYou're right there were lots of storms and meteorites.  For all we know, life needed a couple of tries to get started.\n\nJust the fact that you are asking whether we came from monkeys or from goo, shows that you either have NO idea what evolution is about or are just trying to get a rise out of people.  You bore me.
163988
The four priciples are:\n1. More individuals are born than survive to reproduce \n2. Heritable variation exists among individuals \n3  Struggle for existence or competition\n4. Adaptation
159232
because they can't adapt to their environment. ones who can't adapt, can't get food or settlement. that's why they became extinct..
184652
All organisms are complex, but some are more complex than others.
464741
Oh sure then.\nAnd I'll tell you what...\nBetween weather changes and Global Warming, a substantial number of upheavals are occurring in the life styles of many species, some to their unfortunate extinction when they change patterns and can't survive within the changed environment anyway.\nMankind is both a blessing and a curse!
323144
This is Darwin's Theory of Evolution known as natural selection:\n\n1. Species have great fertility. They make more offspring than can grow to adulthood. \n\n2. Populations remain roughly the same size, with modest fluctuations. \n\n3. Food resources are limited, but are relatively constant most of the time. From these three observations it may be inferred that in such an environment there will be a struggle for survival among individuals. \n\n4. In sexually reproducing species, generally no two individuals are identical. Variation is rampant. \n\n5. Much of this variation is heritable.
1133442
Actually, Darwin was a religious man who sought to understand the ways in which God did things.  The idea that evolution was created to replace God was not his own.
135214
survival of the species ,to procreate
489077
they'd need to replace humans with dolphins or some other species that wasn't so aggressive.