Identify and describe Early Beliefs: Creationism, Charles Darwin and His Observations and Variation Within Species in the context of theory of evolution (biology only).
BEEZYREVISOR
GCSE Biology Revision
Learn it. Recall it. Revise it.
GCSE Biology revision
Theory of evolution (biology only)
The development of understanding of genetics and evolution
Your specification
AQA student objectives
Learning pathway
All · Most · Some
Explain the relationships between Early Beliefs: Creationism, Charles Darwin and His Observations and Variation Within Species and how they contribute to theory of evolution (biology only).
Apply and analyse knowledge of Early Beliefs: Creationism, Charles Darwin and His Observations and Variation Within Species to interpret unfamiliar information about theory of evolution (biology only).
Revision summary
Key knowledge
Read on screen, then print for Cornell-style active revision.
Early Beliefs: Creationism
- Before the 18th century, the dominant view was creationism — the belief that a God created all living organisms on Earth from nothing.
- This understanding meant that the diversity of life was seen as fixed and divinely designed, rather than the result of natural processes.
Charles Darwin and His Observations
- Charles Darwin travelled to the Galápagos Islands, where he spent long periods observing the variety of life found there.
- Darwin collected extensive evidence over his lifetime, which he used to develop and support his theory of natural selection.
Variation Within Species
- Darwin observed that individual organisms within the same species show variation in their characteristics, for example, some giraffes have longer necks than others.
- This natural variation is the foundation of Darwin's theory, as it means some individuals are better suited to their environment than others.
Natural Selection and Survival of the Fittest
- Individuals with characteristics better suited to their environment are more likely to survive long enough to reproduce successfully.
- For example, giraffes with longer necks can reach leaves higher in trees, giving them a food advantage when resources are scarce.
- The phrase 'survival of the fittest' refers to those individuals with the most advantageous characteristics being most likely to survive and reproduce.
Inheritance of Advantageous Characteristics
- Parents who survive due to their advantageous characteristics pass those traits on to their offspring through their genes.
- Over many generations, these beneficial characteristics become more common in the population, leading to gradual evolutionary change.
- Natural selection is a very slow process and changes are only observed after many, many generations.
Controversy Surrounding Darwin's Theory
- Darwin's theory caused significant controversy, particularly among creationists who believed God had created all plants and animals.
- At the time, the understanding of genetics was still in its infancy, meaning Darwin could not fully explain why variation existed between organisms.
- The lack of genetic evidence was Darwin's greatest challenge, and it took approximately 50 more years after publication for this understanding to develop.
- Despite proposing one of the most important scientific theories, Darwin did not receive full recognition for his work during his lifetime.
Darwin's Published Work
- Darwin published his findings in a book known as 'On the Origin of Species', which outlined his theory of evolution by natural selection.
- The reception of this work was affected by the lack of genetic evidence available at the time to support his ideas.
Lamarck's Theory: Inheritance of Acquired Characteristics
- Jean-Baptiste Lamarck proposed an alternative theory of evolution known as the inheritance of acquired characteristics.
- Lamarck suggested that changes an organism develops during its lifetime — such as a giraffe stretching its neck to reach higher leaves — would be passed on to its offspring.
- Another example would be two parents who build significant muscular strength; according to Lamarck, their child would inherit that muscular strength.
Why Lamarck's Theory Was Rejected
- Lamarck's theory is not accepted today because we now understand that it is genetic information, not physical changes acquired during a lifetime, that is passed on to offspring.
- Stretching your neck or building muscle does not alter your DNA, so these acquired traits cannot be inherited by the next generation.
Comparing Darwin and Lamarck
- Darwin's theory of natural selection is the currently accepted scientific explanation for how species evolve over time.
- Lamarck's theory incorrectly proposed that characteristics acquired through an organism's behaviour or environment could be directly inherited.
- The key difference is that Darwin focused on inherited genetic variation and survival advantage, whereas Lamarck focused on changes made during an organism's lifetime being passed on.