Page 3: Earth's History and Reproductive Technologies
This page covers Earth's age, reproductive technologies, and further details on evolution and speciation.
The Earth is approximately 4.5 billion years old, providing a vast timescale for evolutionary processes.
Reproductive technologies discussed include:
- Embryo transplants
- Artificial insemination
- Adult cell cloning (first occurred in 1996)
Example: Adult cell cloning involves removing the nucleus from an unfertilized egg, inserting the nucleus of an adult body cell, and stimulating division with an electric shock.
Darwin's Theory of Evolution faced initial rejection due to:
- Conflict with religious beliefs
- Insufficient evidence at the time
- Lack of understanding about inheritance mechanisms
Highlight: Why were Mendel's ideas not accepted initially? Similarly, Darwin's ideas challenged existing beliefs and lacked supporting evidence from genetics.
Alfred Wallace contributed to evolutionary theory by studying warning coloration in species and developing ideas on speciation. Wallace and Darwin published their joint ideas in 1858.
Definition: Speciation is the formation of two or more species from an original species, often due to genetic variation, natural selection, or isolation.
The page emphasizes that new species can occur through:
- Genetic variation
- Natural selection
- Speciation
- Isolation leading to adaptations to new environments
Vocabulary: Reproduction and Inheritance GCSE Biology topics often include terms like "speciation," "genetic variation," and "natural selection" to explain how species evolve and diversify.
This comprehensive overview of evolution, speciation, and reproductive technologies provides essential knowledge for AQA GCSE Biology inheritance, variation and evolution past papers and exam questions.