So you think we came from monkeys

These arguments usually come from the misunderstanding of the science. They are examples of Straw man arguments.

We came from Pond soup
This refers to the theory of Abiogenesis which generally is interpreted as a small pond wherein amino acids are formed with electricity, most probably from lightning. This claim isn't as absurd as some of the other ones around, yet is still relatively wrong. There is nothing about soup in abiogenesis, and if queried further, the intellect of the theist (presumably) will become apparent. Abiogenesis explains a theory of how life came to be, not the universe (for clarification).

We came from dirt/rock/clay
This also refers to the theory of Abiogenesis, life originating from non-living material. If the theist is a Biblical literalist, it's worth pointing out that the book of Genesis says that God made man from dirt.

We came from Nothing
Typically, this version is in reference to the Big bang. This notion is known to be used by apologists such as Ray Comfort and Kirk Cameron in an episode of 'The way of the master', a tv series hosted by the two. When the argument is used, it is usually used flippantly, without real understanding. At the Big bang, there was matter and energy before, as a singularity. Since science does not yet have any answers about what happened "before" the Big bang, the intellectually honest position taken by most atheists is that we don't know. For some reason, the Big bang is often misinterpreted as a "something from nothing" proposition. Some physicists, such as Victor Stenger, have some ideas how this may be the case, however, for the moment, it's speculation.

Abiogenesis and Evolution are also occasionally misunderstood to be "something from nothing" concepts.

We came from Monkeys/Apes
This version of the argument refers to evolution; in particular, the evolution of the human race. A common misconception about evolution is that we evolved from the monkeys and apes we see today. This ignorance led to the argument of, "If we evolved from monkeys and apes, then why are there still monkeys and apes?".

Part of the difficulty of this issue is definitional. "Monkeys" and "Apes" are families in the evolutionary tree. Modern Homo sapiens are in the "Great Ape" family (also known as Hominidae), alongside several other species, such as gorillas and chimpanzees. With this general classification, the common ancestor of humans and chimpanzees was also within an ape family, but that common ancestor species is now gone, having ultimately split into modern humans and chimpanzees. Colloquially, "monkey" is thought to be a specific species, but technically, it isn't.

We didn't evolve from any modern monkeys or apes. Modern humans, monkeys and apes evolved from different common ancestors that branched off to form a tree of species, in different families, in which we are included. What Creationists are incorrect about is that species branch apart, typically due to geological separation, and not merely in a straight line. It's a common misconception that evolution is a ladder, when in fact, it's a tree.

There are approximately 5,400 known species of mammals on the planet, which all arose and flourished after the reptiles were decimated by the apparent comet or asteroid that impacted the earth some 65 million years ago. The earliest known precursors to mice, opossums, and other marsupials were the largest mammals in the late Cretaceous and early Paleocene, and the primates arose from that point out into separate directions. Some of these species hit a dead end and others didn't. Some were viable and survived. After humans and chimpanzees broke away from their common anscestor, several species of hominids arose in the Homo genus, such as Homo erectus, Homo neanderthalensis and Homo sapiens. Out of the those 9 species, only one avoided extinction: Homo sapiens (humans).

The following questions mirror the understanding/logic of this argument:
 * If Americans came from Europe, why are there still Europeans?
 * If I came from cousins, why do cousins still exist?