So long as they [birth control methods] ... remained taboo subjects the chances of making any impression on the human population explosion were that … - Prince Philip, Duke of Edinburgh

It is frequently more rewarding merely to ask pertinent questions. It may get someone to go and look for an answer. If you get a silly answer, which can easily happen, you can return to the charge with even more telling effect. Whatever happens, don't give up and don't despair. Results may not be immediately apparent, but you may have touched a receptive chord without knowing it. Even the most unsympathetic and unenlightened politician, industrialist or bureaucrat begins to take notice when a lot of people write about the same subject.

As long ago as 1798, Malthus explained what happens when the factors limiting the increase in any population are removed. One of the factors noticed by Darwin was that all species are capable of producing vastly greater populations than can be sustained by existing resources; populations did not increase at the rate at which they are capable was the basis for his theory of Evolution by Natural Selection.
The relevance to natural selection of this capacity for overproduction is that as each individual is slightly different to all the others it is probable that under natural conditions those individuals which happen to be best adapted to the prevailing circumstances have a better chance of survival. Well, so what? Well, take a look at the figures for the human population of this world. One hundred fifty years ago it stood at about 1,000 million or in common parlance today, 1 billion. It then took about a 100 years to double to 2 billion. It took 30 years to add the third billion and 15 years to reach today's total of 4.4 billion. With a present world average rate of growth of 1.8%, the total population by the year 2000 will have increased to an estimated 6 billion and in that and in subsequent years 100 million people will be added to the world population each year. In fact it could be as much as 16 billion by 2045. As a consequence the demand on resources of land alone will mean a third less farm land available and the destruction of half of the present area of productive tropical forest. Bearing in mind the constant reduction of non-renewable resources, there is a strong possibility of growing scarcity and reduction of standards. More people consume more resources. It is as simple as that; and transferring resources and standards from the richer to the poorer countries can only have a marginal effect in the face of this massive increase in the world population.
The object of the WWF is to "conserve" the system as a whole; not to prevent the killing of individual animals. Those who are concerned about their conservation of nature accept that all species are prey to some other species. They accept that most species produce a surplus that is capable of being culled without in any way threatening the survival of the species as a whole.

Can you tell the difference between them?