Human Evolution
In 2013–2015, Lee Berger's team at the University of the Witwatersrand recovered 1,550 fossilised Homo naledi bones from Rising Star Cave in South Africa — representing 15 or more individuals. The discovery was remarkable not just for its scale but for what the fossils showed: Homo naledi combined modern-human-like feet and hands with ape-like curved fingers and a tiny brain case of just 560 cc. This mosaic of primitive and modern features directly challenged the simple "ladder of progress" model of human evolution in which bigger brains always evolved first.
Practise this lesson
Four printable worksheets that build from the foundations up to exam-style questions — start at whatever level suits you.
Commit to your first interpretation before we build the evidence properly.
1. If humans and chimpanzees share a common ancestor, does that mean humans descended from modern chimpanzees?
2. If brain size increases across some hominid species, does that mean human evolution was a straight line from small brain to big brain?
Know
- The main hominid species named in the syllabus.
- The key morphological trends in the hominid record.
- The difference between fossil and molecular evidence.
Understand
- Why humans are one great-ape lineage rather than separate from ape evolution.
- Why human evolution is branching rather than linear.
- Why multiple evidence types are needed because the fossil record is incomplete.
Can Do
- Describe bipedalism, brain-size and jaw changes through time.
- Summarise key hominid species accurately.
- Evaluate what fossils and ancient DNA can and cannot tell us.
Core Content
Humans are one branch of the ape family, not a species that stepped out of evolution separately
In 2013–2015, Lee Berger's team at the University of the Witwatersrand recovered 1,550 Homo naledi fossils from Rising Star Cave — 15 or more individuals. The fossils showed human-like hands and feet alongside a brain case of only 560 cc, a mosaic of features that makes no sense if human evolution was a straight line from primitive to modern. This discovery illustrates a key fact: humans are one of the great apes in the family Hominidae, sharing a common ancestor with chimpanzees, not descending from modern chimpanzees, and our evolutionary history is far more branched and overlapping than a simple ladder.
Several morphological trends appear repeatedly in the hominid record. Bipedalism is inferred from a more central foramen magnum, a broader pelvis, an inward-angled femur and the development of a foot arch. Brain size increases overall across many hominid species. Jaw shape becomes less prognathous, canine teeth reduce, and the dental arcade becomes more parabolic in Homo. Bipedalism is inferred from a more central foramen magnum, a broader pelvis, an inward-angled femur and the development of a foot arch. Brain size increases overall across many hominid species, although the pathway is not perfectly smooth. Jaw shape becomes less prognathous, canine teeth reduce, and the dental arcade becomes more parabolic in Homo. Tool use also becomes more sophisticated, from Oldowan stone tools to Acheulean hand axes and later modern technologies.
Bipedalism
Central foramen magnum, broader pelvis, angled femur, arched foot.
Brain Size
Rough increase from about 450 cc to about 1350 cc across major taxa.
Jaw and Teeth
Reduced prognathism, smaller canines, more parabolic dental arcade.
Pause — copy the highlighted bipedalism evidence and morphological trends into your book before the check below.
Which statement about humans and chimpanzees is most accurate?
From Australopithecus afarensis to Homo sapiens, with Homo naledi disrupting simple stories
We just saw that bipedalism and morphological trends are traceable across hominid species. That raises a question: which key species make up this record, and do they form a neat progression? This card answers it → the hominid timeline is a branching pattern, and Homo naledi specifically breaks the idea that "more recent always means more advanced".
The hominid record is best understood as a branching pattern reconstructed from many fossil discoveries, not as a single neat ladder of progress.
| Species | Approximate Date | Why It Matters |
|---|---|---|
| Australopithecus afarensis | ~3.2 MYA | Lucy; clearly bipedal but still small-brained, showing that upright walking came before large brains. |
| Homo habilis | ~2.4–1.4 MYA | "Handy Man"; associated with regular stone-tool use and a larger brain than Australopithecus. |
| Homo erectus | ~1.9 MYA–117,000 years ago | Used fire, made Acheulean tools, and was the first Homo species to leave Africa. |
| Homo naledi | ~335,000–236,000 years ago | Announced in 2015; mosaic of primitive and modern features, showing human evolution was more complex than a simple brain-size ladder. |
| Homo sapiens | ~300,000 years ago to present | Modern humans; African origin, later Out of Africa dispersal, and interbreeding with Neanderthals and Denisovans. |
Key hominid species: A. afarensis (Lucy) — bipedal, small brain; H. habilis — stone tools; H. erectus — fire, left Africa; H. naledi — mosaic traits disrupting simple linear stories; H. sapiens — interbreeding with Neanderthals and Denisovans confirmed by ancient DNA.
Pause — copy the highlighted species summary table into your book before the check below.
Why is Australopithecus afarensis especially important?
Why the record is incomplete but still powerful when multiple lines of evidence agree
We just saw that hominid species form a branching rather than linear timeline. That raises a question: how confident can we be in this reconstruction given incomplete evidence? This card answers it → no single source is enough, but fossil evidence, archaeology and ancient DNA each contribute different strengths that together support a reliable picture.
No single fossil or DNA sample tells the whole story. Human evolution is reconstructed by combining incomplete fossils, anatomical comparisons, archaeological evidence and, where available, molecular data.
| Evidence Type | Strengths | Limitations |
|---|---|---|
| Fossil bones | Show anatomy directly; reveal posture, skull shape, teeth, pelvis and limb structure | Fossil record is incomplete and preservation is uneven |
| Stone tools / archaeology | Show behaviour and technology associated with hominids | Tools do not always identify the exact maker with certainty |
| Ancient DNA | Tests relatedness directly and can reveal interbreeding between lineages | Only survives in some conditions; unavailable for many older fossils |
Ancient DNA from archaic humans is one reason we know modern non-African populations carry Neanderthal and Denisovan ancestry. But DNA cannot be extracted from every fossil, especially very old ones or those from unsuitable environments. Fossil evidence shows anatomy directly (skull, pelvis, limbs) but record is incomplete. Ancient DNA tests relatedness and can detect interbreeding, but is not available for all fossils. Multiple converging lines of evidence together give a stronger reconstruction than any single source — human evolution is best represented as a branching tree.
Pause — copy the highlighted evidence strengths and limitations into your book before the check below.
What does ancient DNA add to the study of human evolution?
Activities
Trait Before Trend
Lucy (Australopithecus afarensis) was bipedal but had a much smaller brain than modern humans. Explain why this is important evidence against the idea that big brains came first in human evolution.
Why Homo naledi Matters
Explain why the 2015 announcement of Homo naledi made scientists more cautious about describing human evolution as a simple straight line from primitive to advanced forms.
True or false: the fossil record is complete enough that no further hominid discoveries are expected to change our understanding of human evolution.
Shared Ancestry
- Humans are one of the great apes.
- Humans and chimpanzees share a common ancestor; humans did not descend from modern chimpanzees.
Morphological Trends
- Bipedalism evidence includes foramen magnum position, pelvis, femur angle and foot structure.
- Brain size generally increases and the jaw becomes less prognathous.
Key Species
- A. afarensis, H. habilis, H. erectus, H. naledi, H. sapiens.
- H. naledi is especially important because it disrupts simple linear stories.
Evidence Quality
- Fossils are incomplete but directly show anatomy.
- Ancient DNA is powerful but not available for every fossil.
- Human evolution is best represented as a branching tree.
A fresh set drawn from this lesson's question bank — feedback shown immediately. +5 XP per correct · +25 XP all correct
Pick your answer, then rate your confidence — that tells the system what to drill next.
UnderstandBand 3–4(4 marks) 1. Describe two lines of evidence for bipedalism in the hominid fossil record.
AnalyseBand 3–4(3 marks) 2. Distinguish between what fossil evidence and ancient DNA evidence can tell us about human evolution.
EvaluateBand 4–5(3 marks) 3. Explain why Homo naledi supports a branching rather than linear view of human evolution.
Show all answers
Multiple choice
MC answers and full explanations are shown inline as you complete each question. Use the retry button to attempt a fresh set from the lesson bank.
Activity 1 — Trait Before Trend
Lucy is important because she was clearly bipedal (inferred from her pelvis, femur angle and foramen magnum position) but had a cranial capacity of only about 450 cc — far smaller than modern humans. This directly contradicts the idea that a large brain was the first trait to evolve. Bipedalism preceded large brains, which means human evolution did not simply scale up brain size first and then add walking ability.
Activity 2 — Why Homo naledi Matters
Homo naledi matters because it has a mosaic of features — some very primitive (small brain, curved fingers) and some more modern (teeth, feet) — in a hominid that lived relatively recently, around 335,000–236,000 years ago. This does not fit a simple ladder model where each later hominid must be more "advanced" than earlier ones. It supports the idea that human evolution was branching, with different lineages following different evolutionary pathways rather than a single progressive chain.
Short Answer Model Responses
SA1 (4 marks): One line of evidence for bipedalism is the position of the foramen magnum [1]. In bipedal hominids it is more central underneath the skull, showing that the head balanced over an upright spine [1]. Another line of evidence is pelvis and leg structure [1]. A broader pelvis and inward-angled femur help support body weight during upright walking. An arched foot can also be used as supporting evidence [1].
SA2 (3 marks): Fossil evidence shows physical structure directly, including skull shape, pelvis shape, jaw projection, tooth size and limb proportions [1]. It is especially useful for reconstructing bipedalism and overall morphology, but the fossil record is incomplete [1]. Ancient DNA can test relatedness more directly and can show interbreeding between lineages such as Homo sapiens and Neanderthals, but it is only available from some remains and environments [1].
SA3 (3 marks): Homo naledi supports a branching view because it combines primitive and more modern traits in the same hominid rather than fitting neatly into a straight ladder from "ape-like" to "human-like" [1]. Its mosaic anatomy shows that different traits evolved at different times and in different combinations [1]. This supports the idea that multiple hominid lineages coexisted and that human evolution was branching rather than linear [1].
Common ancestor, not ancestor
Humans and chimps share a common ancestor ~6–7 MYA. Chimps are our closest living relatives — not our ancestors.
Bipedalism first
Lucy shows upright walking before large brains. Four clues: central foramen magnum, broad pelvis, angled femur, arched foot.
Branching, not ladder
Multiple hominid species coexisted. Homo naledi's mosaic traits break the simple primitive-to-modern narrative.
Evidence synthesis
Fossils show morphology. Ancient DNA tests relatedness. Neither alone is enough — convergence of evidence strengthens the reconstruction.
Rapid-fire questions on hominid species, morphological trends and evidence evaluation. Beat the boss to bank a tier — gold (perfect + fast), silver (80%+), or bronze (cleared).
The most reliable way to avoid common mistakes here is to separate "common ancestor" from "direct ancestor", and "overall trend" from "single straight line". Human evolution contains branching, coexistence and unexpected trait combinations.
The 2013–2015 Rising Star Cave discovery of 1,550 Homo naledi fossils by Lee Berger's University of the Witwatersrand team is the clearest recent demonstration that the "ladder of progress" model is wrong. Homo naledi combined modern-human-like feet (suggesting bipedalism) with a brain case of only 560 cc and ape-like curved fingers (suggesting tree-climbing). This mosaic species coexisted with other hominids at a time when the simple linear model predicted brain enlargement should have been complete. Human evolution is a branching tree, not a ladder — and 15 individuals found in a single South African cave proved that point more powerfully than any previous discovery.