Category Archives: Unit 1 Biology

Biological Classification


Classification of living organisms has been a human pastime throughout history – it is important that we can name and identify organisms, especially if they are harmful (venomous snakes and spiders for example) or beneficial (organisms that provide food, fibre, medicine or services). It also helps us to group and organize the huge variety of living organisms on our planet. The science of identifying and naming organisms is referred to as ‘taxonomy’. Carl Linnaeus, a Swedish scientist, is often referred to as the ‘father of taxonomy’ because he developed the naming system that we still use today, called binomial nomenclature, which literally means “two-name naming-system”. Every organism belongs to a particular species and is identified by two latin words – the Genus and species. So, Homo sapiens (modern humans) belong to the genus Homo and species sapiens. Note that the genus name is capitalized, but the species name is not.

Two organisms that belong to the same genus (Eg. Eucalyptus citriodora and Eucalyptus camaldulensis) are more closely related than two organisms with the same species name (Eg. Eucalyptus citiodora and Backhousia citriodora). This is because the species name (citriodora) is a descriptive name that can refer to a characteristic of different groups, in this case, Lemon-scented Gum and Lemon-scented Myrtle.

Within the Five Kingdoms of Living organisms (Protists, Prokaryotes, Fungi, Animals and Plants) are the Phyla, Classes, Orders, Genera and species. It helps to remember this sequence of groups:

  • Kingdom
  • Phylum (and sub-phyla)
  • Class (and sub-class)
  • Order (and sub-order)
  • Genus
  • Species

Some more resources to learn about classification:

Fern Reproduction – Alternation of Generations


1. Watch the Secret Life of Ferns; the Fern Life Cycle and the Fern sporangium catapult on YouTube.

2. Go to The Fern Life Cycle – Student Tutorial and label the Fern Life Cycle diagram as you work through the tutorial.

3. Use this worksheet to create a new task for next year’s Biology class to learn about the Alternation of Generations in ferns.

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This image is a screenshot from the YouTube video “The fern sporangium catapult” showing spores being released from a sporangium and the annulus colored blue, representing the water that is critical to the process of ejecting the spores. Due to the cohesive properties of water molecules and the structure of the annulus, as water evaporates, the sporangium ruptures as the annulus curls back. At a critical point, when water continues to evaporate, there are not enough water molecules to hold the annulus open and the ‘head’ of the sporangium springs back, ejecting the spores.

Term 2 – Week 5: Reproduction (Year 11)


This week in Year 11 Biology we are starting to discuss another body system – the reproductive system. First we will study the concepts of asexual and sexual reproduction and then learn how reproduction occurs in unicellular and multicellular organisms.

Asexual Reproduction – Plants, bacteria and fungi

Draw a diagram to show each of the following types of asexual reproduction:

  • binary fission (eg. bacteria, some algae)
  • budding (eg. yeast, hydra)
  • bulbs (eg. daffodils)
  • runners and rhizomes (eg. strawberries)
  • fragmentation (eg. sea stars, flatworms)
  • spore formation (eg. fungi)
  • parthenogenisis (eg. stick insects, some reptiles)

This YouTube video, Asexual Reproduction, shows budding in Hydra and Anenomes and binary fission in Paramecium, as well as asexual reproduction in Volvox, a green algae.

Sexual Reproduction Handout

Rat Dissection



Today we planned to do a rat dissection, but due to the frosty state of our subjects, we have postponed this investigation until Tuesday. In the meantime, we will answer the questions we can, using digital resources:

Plant adaptations for dry environments.


Terrestrial plants need to maintain their water balance, while still allowing the exchange of gases between the plant cells and the external environment. Gas exchange occurs through stomata, which also allows the escape of water vapour. The image above shows a cross section of a leaf from Marram grass, common on sand dunes, where it is very salty and often dry. You can see how the leaf is rolled, creating an internal micro-climate that is much more humid than the external environment. This reduces water loss and allows stomata to remain open, even in the driest of climates. PIne needles (Pinus) and Casaurina also have cylindrical leaves, an adaptation for dry environments.


The sunken stomata in this image (cross section of a leaf) allows a moist layer of air above the stomata, protecting the leaf from excessive evaporation.


This image shows a cross section of a leaf from a plant adapted to a very arid environment. The stomata are sunken into pits with lots of epidermal hairs, which provide a humid micro-climate, allowing the stomata to remain open, despite very dry external conditions.


Distribution of Materials


Image Source

In this unit of work we are looking at the ways plants and animals distribute nutrients, hormones, gases, water and waste products to and from different cells throughout the organism. In animals, this involves the circulatory, respiratory and excretory systems. In vascular plants, we consider gaseous exchange, transpiration and substances moving through the xylem and phloem.

Circulatory System: Once food has been digested, these nutrients needs to be distributed to every cell within the body to enable cellular respiration to occur. These nutrients, as well as hormones, waste products (CO2 and urea), salts and heat are transported in the circulatory system. The circulatory system of mammals includes  a four-chambered heart, arteries, veins and capillaries that allow the movement of blood to every cell within the body.

Respiratory System: The mammalian respiratory system includes the lungs, trachea, bronchi and alveoli that allow the transfer of oxygen and carbon dioxide between the internal blood supply and the external environment. Insects have an open respiratory system in which the air and the internal cells are in close contact, oxygen entering through spiracles and passing in to branching tubes within the organism. Don’t get confused between cellular respiration and breathing! Cellular respiration is the process that converts glucose and oxygen to energy within the cells. Oxygen is supplied to those cells by the red blood cells, which carry oxyhaemoglobin to cells and remove carbon dioxide from cells.

Excretory System: Our kidneys are part of our excretory system, to remove nitrogenous wastes from our body. The nephron is the functioning unit that removes urea from the blood and allows water, nutrients and salts to be re-absorbed to the body. Ureters are the tubes that carry urea from the kidneys to the bladder and urine leaves the body via the urethra.

Gaseous Exchange in Plants: Plant cells need to exchange oxygen and carbon dioxide with the environment and they do so through stomata (pores) in their leaves.

Transpiration: How do the tallest trees draw water from the soil to hydrate leaves many metres in the air?

Xylem and Phloem in Vascular Plants: What are vascular plants and how do they transport water with dissolved minerals and nutrients to cells in the roots, stems and leaves?

Please let me know in the comments below if any of these links are no longer working!

Mammalian Digestive System


Image Source – Attribution: By Leysi24 (Own work) [CC BY-SA 3.0  via Wikimedia Commons

Firstly, dismantle the human torso model in the science laboratory and describe what you know about each part of the alimentary canal and associated glands and organs. Draw and label  a detailed diagram, showing each of the organs above. Then complete the “Cut-and-Paste your Guts” activity, identifying each organ from it’s description and pasting each description into your book, in the order that food would pass through, on it’s 12 hour journey through the 7 metres of the digestive system.

Next, match the skulls (noting the teeth structure and position of eye sockets) with the corresponding herbivore, omnivore and carnivore digestive systems. Describe the diet of each organism, explaining your reasoning in terms of teeth structure, size of stomach and length of intestines, any enlarged organs and corresponding diet.

Term 1 Study Break

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Unit 1 – Year 11 Biology 

  • Read Chapter 5 – Obtaining Energy and nutrients for life.
  • Make sure you understand the key terms and definitions (pg 125).
  • Complete Chapter 5 Review Questions.
  • Create a set of study notes for Unit 1: Area of Study 1: Cells in Action
  • Download Mr Barlow’s Unit 1 and Unit 2 Biology apps from the iTunes or Google store.

 Unit 3 – Year 12 Biology

Cupcake mitosis


Students in Year 11 Biology are learning the phases of mitosis, so we baked and decorated these cupcakes. Students now have a good understanding of what happens inside the nucleus during:

  • Interphase
  • Prophase
  • Metaphase
  • Anaphase
  • Telophase and
  • Cytokinesis.

Watch the Cells Alive Interactive and describe where in each cycle are the three checkpoints that allow DNA replication and mitosis to continue. Why is it incorrect to suggest that the cell is “resting” during interphase, between mitotic cycles?

Mutants can be beautiful!


Both these roses come from the same bush in my garden at home. The one on the left is how the rose normally looks, year after year. This year, on a single branch sprouting to the side, there are about six flowers that look striped, like the one on the right. This article, from the American Rose Society, describes how a genetic mutation can cause this change in pigments.

Stripes may also result from spontaneous or induced mutations. Mutations are sudden changes that occur at a very low frequency in a gene. Spontaneous mutations (popularly known as ‘sports’) alter the existing genes and their expression, resulting in stripes. Induced mutations by irradiation or chemical mutagens also lead to genetically-altered  pigmentation, and the result is stripes. Stripes may develop as a result of the transmission of genes responsible for stripes through hybridization. Viral infection that causes variegation in tulips may also cause stripes in roses. These infections could interfere with physiological functions of pigmentation, giving them a striped appearance.

It is possible that a mutation has occurred during mitosis somewhere at the base of the new branch and all the cells in the new branch carry the mutated gene, which is expressed as a striped phenotype. If this is the case, a cutting from this branch will also produce striped flowers. So, I will take a cutting and propagate this rose, to see if we can produce more of these beautiful mutants!