Use this form to email 'If evolution is real why are there still monkeys? By clicking 'Send to a friend' you agree ABC Online is not responsible for the content contained in your email message. Skip to navigation Skip to content. This site is being redeveloped. For all the latest ABC Science content click here. Site Navigation Video Audio Photos. How can we be descended from monkeys if there are monkeys around today?
Johnson, James J. The American Biology Teacher 1 February ; 74 2 : 74— Teachers may be posed with such questions as, "If we evolved from chimps, why are there still chimps? We also provide references they can use to further students' understanding of human evolution and evolution in general. In the process, we highlight recent discoveries in paleontology, molecular evolution, and comparative genomics. Modern chimps and humans shared a now extinct common ancestor that was neither a chimp nor a human — in other words, humans did not evolve from chimps — and, though chimps are humans' closest living relatives, we are characterized by distinct evolutionary histories.
Biology educators, whether they teach in high schools or in colleges and universities, may get a question similar to the one in our title. How should they respond? Such questions can provide excellent teaching moments.
In the following pages, we provide answers to this and related questions. Our main point: Chimps are still around today because humans did not evolve from living chimps 1 — both humans and chimps evolved from a now extinct common ancestor. To better understand the distinct evolutionary histories of humans and chimps, we must begin with a discussion of two evolutionary patterns: anagenesis and cladogenesis. Question: Did humans evolve in a "straight line," with one species evolving into another?
Answer: Evolution does not just proceed along a straight line; it also branches. Anagenesis is an identifiable pattern, or outcome, characterized by directional evolutionary changes within a single lineage. By contrast, cladogenesis branching evolution leads to the origin of two or more lineages from a common ancestor Figure 1 Futuyma, Evolutionary biologists consider cladogenesis a much more important pattern in the generation of biological diversity than anagenesis.
The term "common ancestor" refers to a set of ancestral populations, not a single individual, that split to give rise to two sets of populations. In the present case, one of these sets evolved to become modern-day humans, while the other evolved to become modern-day chimps. With regard to terminology, we recommend referring to the common ancestors of living chimps, living humans, and all the extinct species that are ancestral to them as "fossil apes" or "ancestral apes" so that these ancestral species are clearly distinguished from living apes.
We hope that this language will help dispel the incorrect idea that humans evolved from living chimps. A Anagenesis versus B cladogenesis. A Anagenic evolution occurs within and is constrained to a single lineage. For example, an ancestral flock of seagulls might change over time, evolving the gray wing tips and increased mean flight speed observed in present-day Species A.
B Cladogenesis involves lineage splitting, leading to two new lineages. For example, present-day Species B and Species C may have evolved from a common ancestral species that was split apart by the appearance of a new river or some other vicariant event.
This resulted in two groups, now separated, where there was once one. Evolutionary changes can now occur independently in these two resulting lineages. Multiple lines of evidence support the hypothesis that cladogenesis and anagenesis occurred within the human lineage after the initial split between the human and chimp lineages.
Species known from the human fossil record are believed to have originated from ancestral forms primarily via lineage splitting, but also via anagenetic change e. With an understanding of cladogenesis and anagenesis, students can better appreciate the distinction between descent from a common ancestor and relationships among coexisting modern species. Answer: No. Just as you and your cousins share a common ancestor who lived hundreds of years ago and are long dead, all living humans share a common ancestor with all living chimps that lived millions of years ago, and that common ancestor no longer exists.
It is important to introduce the concept of evolutionary cousins to help clear up misconceptions about humans evolving from modern chimps. Note that this statement reflects the fact that diversification of species occurs via cladogenesis, as described earlier. Explaining the difference between a student's living relative in the same generation a distant cousin and the dead relative from a few generations ago that the student and his or her cousin share a great-great-grandparent is an effective method for introducing the concept of a common ancestor.
With this analogy, students can better grasp the notion that they did not descend from living apes, just as they did not descend from their cousins. Students can also be introduced to the concept of close versus distant relatives; just as a student and his or her sibling are genetically more closely related to each other than either is to a cousin, humans and chimps are genetically closer to each other than either is to monkeys or any other species of ape.
This should help correct the related misconception that evolution is always linear. As Dougherty suggests, this can be a teachable moment: present to your students a series of incorrect statements based on common misconceptions, and ask them to find the errors and rewrite the statements to be correct.
Before discussing the changes that have occurred along the human and chimp lineages since humans and chimps diverged, we need to discuss the currently observable similarities and differences between living chimps and humans. Notably, the relative brain size of humans is significantly larger than that of any other primate, including chimps Striedter, Further, human intellectual capabilities surpass those of chimps, as does the complexity of human communication and cultural practice.
In addition, chimps and humans differ substantially in overall body anatomy. What does genetics say about similarities and differences between humans and chimps? At the chromosome level, humans and chimps are very similar. How can we tell? After being treated by various stains, chromosomes in a karyotype acquire a banding pattern that is somewhat similar to the barcodes one uses at the supermarket to identify products. The banding patterns of human and chimp chromosomes highlight their chromosomal similarities and differences.
With one exception, chimp and human chromosomes can be paired up such that each human chromosome has a corresponding chimp chromosome. The exception to this is human chromosome number 2. Chimps have 24 pairs of chromosomes. Based on the chromosomal banding patterns and from the fact that other nonhuman primates share the chimp chromosome pattern, biologists hypothesize that two of the chromosomes in the human—chimp common ancestor population ultimately fused into one chromosome somewhere along the human lineage.
DNA evidence has confirmed the fusion hypothesis. In fact, biologists know the exact position on the chromosome — down to the nucleotide! Humans and chimps also share similarities in the sequence of nucleotides in their DNA.
Comparing base changes at single nucleotide sites, humans and chimps differ by 1. Still, even the 1. Answer: It depends on what trait or gene you are considering. Let's consider three possibilities regarding relative evolutionary rates between the human and chimp lineages since they diverged from their common ancestor Figure 2. Scenario I: More evolutionary change has occurred within the human lineage since the split. Scenario II: More evolutionary change has occurred within the chimp lineage since the split.
Scenario III: Since the split of the lineages, the amount of evolutionary change has been roughly equal in each of the lineages. Three hypotheses for relative degrees of evolutionary change in the human and chimp lineages since their divergence from a common ancestor.
Most went extinct without giving rise to other species. Some of the extinct hominids known today, however, are almost certainly direct ancestors of Homo sapiens. While the total number of species that existed and the relationships among them is still unknown, the picture becomes clearer as new fossils are found. Humans evolved through the same biological processes that govern the evolution of all life on Earth. See "What is evolution? Learn More Origins of Humankind. A society's culture consists of its accumulated learned behavior.
Human culture is based at least partly on social living and language, although the ability of a species to invent and use language and engage in complex social behaviors has a biological basis. Some scientists hypothesize that language developed as a means of establishing lasting social relationships. Even a form of communication as casual as gossip provides an ingenious social tool: Suddenly, we become aware of crucial information that we never would have known otherwise.
We know who needs a favor; who's available; who's already taken; and who's looking for someone -- information that, from an evolutionary perspective, can mean the difference between failure and success. Scientists think this creature looked more like a chimpanzee than a human, and it probably spent most of its time in the canopy of forests dense enough that it could travel from tree to tree without touching the ground, Isbell said.
Scientists think ancestral humans began distinguishing themselves from ancestral chimps when they started spending more time on the ground. Perhaps our ancestors were looking for food as they explored new habitats, Isbell said.
It was more recently — maybe 3 million years ago — that these ancestors' legs began to grow longer and their big toes turned forward, allowing them to become mostly full-time walkers.
They would have had to travel more on the ground in places where trees were more spread out. The rest is human evolutionary history.
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