Monthly Archives: August 2016

The Science of Human Evolution

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human_evolution

Video Source (YouTube, 54.42 min)

  1. What vestigial organ, a remnant from our primate ancestors, is apparent in humans?
  2. Which species does the video refer to as our “distant cousins”?
  3. Name three characteristics that we share with these monkeys.
  4. Notharctus tenebrosus is a fossil that scientists believe to be a common ancestor of humans – how old is this fossil?
  5. What feature of this fossil’s hand is important for climbing and gripping objects?
  6. How was colour vision an important evolutionary advantage in early primates?
  7. What genetic mutation occurred to allow primates to see in colour like humans?
  8. What sense diminished as humans evolved high-colour vision? What evidence is there for this?
  9. ‘Lucy’ is a 3.2 million year old fossil from Ethiopia – why is this fossil significant?
  10. What advantages does this particular characteristic give the species?
  11. What disadvantages does bipedalism have for modern humans?
  12. What characteristic of stone-age man is an indication that human ancestors had the ability for complex thought, together with highly developed hand-eye co-ordination?
  13. In what test do 3 month old monkeys out-perform human babies?
  14. What fundamental brain architecture do all vertebrates, including sharks and humans, share?

The Hardy-Weinberg Principle of Allele Frequencies

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895px-Hardy-Weinberg

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The Hardy-Weinberg Principle is a mathematical law that predicts allelic frequencies, making several assumptions:

  • Large population
  • Random mating
  • No immigration
  • No emigration
  • No natural selection

In nature, these assumptions are extremely unlikely to occur, but it is the deviation from the expected distribution of alleles (according to the HW Principle) that informs us about the action of these natural conditions.

Please complete Activity 13.2 (page 141) Looking at Allele Frequencies – Parts A and B.

Unit 4: Area of Study 2: Change over time

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Sperm_whale_drawing_with_skeleton

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“The theory of evolution by natural selection, first formulated in Charles Darwin’s book “On the Origin of Species” in 1859, is the process by which organisms change over time as a result of changes in heritable physical or behavioral traits.”

“Natural selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin, and it is now regarded as be the main process that brings about evolution.”

What is the evidence for evolution? from Stated Clearly (YouTube, 11.21min)

  • Fossil evidence – organisms have changed over time and some have become extinct
  • Comparative morphology (anatomy) – there are similarities between some organisms that suggest a common ancestor
  • DNA evidence – Similar species have more genes in common than dissimilar species, suggesting a common ancestor; Chimpanzees and humans have 99% of their DNA in common
  • Distribution of species (biogeography) shows that islands have unique species, due to an original inhabitant becoming adapted to its’ environment over many generations, by natural selection
  • Similarities of embryos suggest that all vertebrates have a common ancestry

Tree of Life video HD with David Attenborough (YouTube, 6.29 min) – Complete the student worksheet – Highlighting important stages in evolution. 

VCE Genetics

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In Chapter 9, you learned about genes, chromosomes and patterns of inheritance, including genotypes and phenotypes, multiple alleles, dominant and recessive genes and co-dominance.

In Chapter 10, you learned about the nature, structure and organisation of the genetic material (DNA), including Mendels’ discoveries with pea plants and the genetic code.

In Chapter 11, you learned about genes in action – replication, transcription and translation to produce the proteins that make up all living organisms.

Chapter 12 is all about the tools and techniques we use to investigate and alter the DNA of organisms – DNA profiling and paternity testing, gene transfer and genetically modified organisms. These processes are newly discovered and there is still community debate about their use. It is important to consider the ethical issues surrounding genetic technologies, as our legal system lags behind scientific knowledge and practice. For example, the recent birth of an IVF baby to a 63 year old woman has made headlines in Australia – she was treated overseas, because the procedure is against the law for women over 53 in this country.