Category Archives: Unit 4 Biology

The Science of Human Evolution

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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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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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“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. 

Exam Revision

Welcome back and thanks for your patience while I have been on study leave. There are only two weeks left before the Unit 3/4 Biology exam on Friday 30th October, so you should have already done the following:

  1. Written out a clear and concise set of study notes, outlining the main concepts in each Area of Study.
  2. Completed practice exams (available at the VCAA website) and identified areas where you need to do further revision.
  3. Joined the Elevate Education #elevatebio Video Series at http://bio.elevateeducation.com/
  4. You may also like to join the Study.com site for a five-day free trial and access their Immunology resources.

Some students have mentioned that they are having most difficulty remembering the cells involved and sequence of events of the cell cycle and immunology. These quick videos and other resources may assist with your revision:

Welcome Back – Term 3!

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Year 12 students will be counting down the next 14 weeks until their VCE Biology exam on the morning of Friday 30th October. We will start this term with a review of the structure of DNA, using the GTAC resources, “Exploring the structure of DNA“.

On Wednesday 22nd July we will be heading to the University of Melbourne Genetics Department to complete three practical activities that will contribute to your school-based assessment:

  1. An investigation using a DNA tool and a manipulation technique
  2. An investigation of inheritance in Drosophila melanogaster including a review of meiosis in gamete formation
  3. Meiosis in Drosophila

On Friday 4th September you will have the opportunity to travel to Brauer College and participate in GTAC outreach program, “From Hominoids to Hominins”.

On Tuesday 13th October you will be able to attend a “Get into Genes” program as revision prior to your exam.

Semester 2 Biology – Adaptations (Y11) and Heredity (Y12)

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This semester we will be starting Unit 2 (Organisms in their Environment) Area of Study 1: Adaptations of Organisms and Unit 4 (Continuity and Change) Area of Study 1: Heredity. We have created Quizlet Sets for each of these topics:

 

VCE Biology 2015

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  Welcome to VCE Biology for 2015! Biology is the study of all living organisms and life itself. So, what do all living organisms have in common?

  1. Living organisms are composed of cells and the products of cells
  2. Living organisms (usually) require oxygen and nutrients (inputs)
  3. Living organisms produce wastes (outputs)
  4. Living organisms respond to stimuli
  5. Living organisms reproduce

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Unit 1: Area of Study 1: Cells in Action (Year 11)

In our first week of Year 11 Biology we will be looking at size and scale, using light microscopes and viewing plant and animal cells. Check out these websites:

Unit 3: Area of Study 1: Molecules of Life  (Year 12)

In our first week of Year 12 Biology we the chemical nature of cells. All living matter is made up primarily of carbon, hydrogen, oxygen, phosphoros, sulfur and nitrogen (CHOPSN). These elements are combined into compounds, with the four classes of biological macromolecules being carbohydrates, lipids, proteins and nucleic acids. Which are which in the diagram below?

biomacromolecules

Human intervention in evolution

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Humans have had an influence on evolutionary processes for much longer than you may have thought – we have tamed wolves and wild cats to become the many breeds of domestic dogs and cats that share our homes today and we have selected cattle, sheep, goats and pigs over many generations for food characteristics. Our main food crops such as rice, corn, wheat, as well as many fruit and vegetables, are very different to their wild ancestors.

Artificial selection, or selective breeding, is the process by which humans breed other animals and plants for particular traits; for example, increased size, fast muscle growth or sweeter taste. This can be a deliberate process, like when farmers choose to breed animals or plants with particular characteristics or it can be accidental. In Asia and Africa, over many centuries, bull elephants with particularly large tusks have been targeted as trophies and for their valuable ivory. As a consequence, individuals with large tusks produce fewer offspring and become less frequent in the population. (Read more about elephant evolution here and here).

In more recent times, due to greater understanding of genetic inheritance and modern gene technology, we have been able to identify specific genes that code for particular characteristics and create new breeds of organisms with beneficial traits – drought tolerance, increased productivity or improved storage life, for example.

Play the videos from ABC Splash “Genetic Engineering of Crops”

Some sites that may be useful for your research project:

Geological time, Fossils and Radiometric dating

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Geological Time Periods

Fossils

Radiometric Dating

Patterns of Evolution

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Speciation: Due to natural variation between individuals, selection pressure, “survival of the fittest” and favourable traits being passed on to offspring over many generations, new species are formed. Biologists refer to allopatric (geographical), sympatric (same location and habitat), and parapatric (habitat differences) speciation.

Divergent Evolution: Over time, due to selection pressures, sub-species or species become less and less alike, as they become better adapted to their niche. Adaptive radiation (below) is a specific type of divergent evolution. The human foot and the foot of a chimpanzee is an example – they are quite different (divergent), although they evolved from a common ancestor, due to the differing habitats of the upright walking man, compared to the knuckle-walking chimpanzee.

Adaptive Radiation: The process by which organisms change over generations to fill different niches, especially when changes in the environment make new resources available. Charles Darwin famously documented the different beak shapes of finches on the Galapagos Islands, which he postulated had arisen form a common ancestor. Above, you can see the variations of honeycreepers from the Hawaiian islands.

Convergent Evolution: In this form of change over time, different species begin to look more alike, despite having no recent common ancestor. Analogous structures develop, that have the same form and function, but were not present in the most recent common ancestor. Examples include flying insects, birds and bats, who have all developed wings as a solution to escaping from predators or finding more food and mates. Hedgehogs and echidnas are a good example of convergent evolution.

Parallel Evolution: Parallel evolution is similar to convergent evolution, in that different organisms display similar characterisitics, but tend to be more closely related. So, gliding frogs for example, evolved in parallel from multiple types of tree frog. Some examples that are closer to home include the Tasmanian tiger and the European wolf; the flying squirrel and gliding possums and marsupial and placental moles/mice.

More about patterns of evolution: