The 3 differences between hominins and hominids

Phylogeny and cladistics are branches of biology whose purpose is to explore the relationships of kinship between species and taxa. Previously, living beings were related based on their morphological characters, but today, genetic studies have broken ground and challenged relationships between many groups animals.

How else to explain that, for example, an amphibian that was a single species suddenly splits into five different population subgroups? Phylogenetic relationships are mobile and subject to change, not because animals evolve very quickly, but because humans increasingly have more tools to know them.

This generates that the terminological divisions are becoming more and more and the general population is confused. This is the case, for example, of the words "hominid" and "hominin", two terms closely related that can generate a hodgepodge of concepts in a person who is not fully dedicated to the anthropology.

What are the main differences between hominins and hominids? Are you clear to which animal family human beings belong? Do you know with which other living beings we share a taxonomic group? Today we answer all these questions.

• Related article: "Primatology: what it is, what it studies, and how it is investigated"

Differences between hominins and hominids: a matter of terms

First of all, it is essential that we make it clear that the term hominid refers to a “family”, a systematic unit that is above the genus, but below the order. Within the family aggregation, the different species can be grouped into subfamilies and infrafamilies, terms included in the "Code International Zoological Nomenclature”, whose purpose is to standardize the chaotic number of concepts that try to cover all the animals of the Land.

Instead, the term hominin refers to a "subtibu", a taxonomic category between family and genus, this word being closer to the latter. Since hominins are a more specific aggregation than hominids, it is not surprising that the first term is contained within the second. Do not despair, because we will explain it in a more friendly way below.

As we have stated, hominins are a subtribe within the hominid family and are characterized by an upright posture and bipedal locomotion. We human beings are hominins and also hominids. Complex, but at the same time simple, right?

Below, we show you some differences between these two groups (of course relative, since one is contained within the other).

1. Members

As the groups are two different concepts, a series of variable animals will belong to them.

For example, since hominids are a term that refers to a family, we can find many more species included in it than if we look only at hominins. Inside to the family hominidae humans and great apes are found, cataloged in these subfamilies:

• subfamily Ponginae:includes orangutans, the second largest primates in the animal kingdom.
• subfamily hominins: Contains humans and their extinct relatives, gorillas and chimpanzees.

As we can see, this more general term does not exclude orangutans, a genus comprising three species that according to studies underwent genetic divergence between them more than 2.5 million years ago. These great apes, native to Indonesia and Malaysia, are characterized by their large sizes (1.50 meters in length), their fine and dense reddish fur, and their arboreal habits. These primates present 3.1% of genetic DNA differences with the rest of hominids grouped in closer subfamilies.

Chimpanzees and gorillas are also within this great family., since they are under the umbrella of the subfamily hominins. The tribe gorillini It includes gorillas, huge primates that usually move on all fours that share 98% of the human genome. They are highly intelligent, corpulent, with black fur and habits that are surprisingly close to those of people in many cases.

Lastly, the tribe hominini It is also within the family of hominids, and this includes gender Bread and to gender Homo. The gender Bread includes the species Pan paniscus and Pan troglodytes, of all life, chimpanzees. Genetic studies show that these cute primates underwent an evolutionary divergence from gorillas 7-8 million years ago, and from the genus Homo only 6 million years ago.

Therefore, it is not surprising that chimpanzees share up to 99% of the genetic code with us humans. These small primates, clearly humanoid in appearance, exhibit hierarchical societies, are capable of deception, and understand many human interactions. Due to our phylogenetic closeness, it is impossible to look a chimpanzee in the eye and not feel a certain part of ourselves in it.

Let's return to terminology after exploring the large family Hominidae. In contrast, the subtribe hominin (yes, which is part of the subfamily hominins and of the tribe hominini) only contains humans, the species Homo sapiens. There is not much more to tell about this category, since this is what it has been designed for, to name only our species.

Following a small concatenation of terms, the classification of the human being would be as follows:

Order Primates - family hominidae - subfamily hominins - tribe hominini - subtribe hominin - gender Homo - species Homo sapiens.

If there is one thing we want to make clear in this hodgepodge of terminology, it is that all great primates are hominins, but not all hominins are hominins. Only we, the human species, find ourselves in the latter category.

• You may be interested in: "Michael Tomasello's Theory: What Makes Us Human?"

2. bipedalism

As we have seen, there is a key characteristic that produces differences between hominins and other hominids: bipedalism. It is clear that a chimpanzee can stand on its two forelimbs at specific moments, but fully bipedal locomotion and skeletal readjustment for it is a privilege only present in humans. In the wild, bipedalism is risky and expensive for several reasons:

• The bipedal posture is not suitable for escaping quickly in dangerous situations.
• It involves enormous skeletal stresses, especially in the spine.
• Changes at the pelvic level make the labor period difficult.
• It takes longer to learn to walk bipedally than in a quadrupedal mode.

Clearly, it's not all downsides. Although bipedalism did not emerge as an evolutionary response to human intelligence, this form of locomotion allowed us to use the hindlimbs for the use and handling of tools, that is, brain development.

3. Morphology

No matter how many similarities that hominins present with the rest of hominids, the differences Morphological characteristics are also palpable, since it is enough to compare the photo of a person with that of a gorilla. For example, the rest of the primates have prehensile feet, since the first toe of these is more robust and is aligned with the remaining four.

Height, weight, hair distribution, and diverse muscle development are also glaring morphological differences between hominins and other hominids. Yes, for example, we all have relatively large brains and a mouth apparatus made up of 32 teeth. Where differences are found, bridges are also built.

conclusions

As we have seen in the previous lines, the term hominin is nothing more than an appreciation to differentiate the human being from the rest of hominoid primates, that is, orangutans, gorillas and chimpanzees.

Despite the differences that we have tried to highlight in this space, it is clear that at compare ourselves with any other animal species, we have much more in common than different with all these primates. This is not a matter of chance, since the 99% genetic relationship that we show with chimpanzees has to be expressed in some way.

If there is one thing we can take away from this dive into the phylogenetic history of higher primates, it is that we are the only hominids alive today, but we share the family hominidae with many other species of living beings. The differences between hominins and hominids, on a large scale and taking into account the diversity of the animal kingdom, are minimal.

Bibliographic references:

• Smith, b. H., & Tompkins, R. L. (1995). Toward a life history of the Hominidae. Annual Review of Anthropology, 24(1), 257-279.
• Steiper, M. AND. (2006). Population history, biogeography, and taxonomy of orangutans (Genus: Pongo) based on a population genetic meta-analysis of multiple loci. Journal of Human Evolution, 50(5), 509-522.
• Zhang, Y. W., Ryder, O. A., & Zhang, Y. Q. (2001). Genetic divergence of orangutan subspecies (Pongo pygmaeus). Journal of Molecular Evolution, 52(6), 516-526.
• zoological, n. (1999). International Code of Zoological Nomenclature.