Image Source – 20 Amazing Animal Adaptations for Living in the Desert
Living organisms are spread across the planet in a wide variety of different habitats and environments. Various adaptations assist organisms to survive in the hottest and driest deserts, coldest arctic tundra and wettest rainforests. Structural adaptations are how an organism is built, such as the wings, feathers and hollow bones of birds that assist them to escape from predators and find their food. Functional or physiological adaptations are how an organism works, which you may not necessarily be able to see from the outside, such as the ability of desert dwellers to survive without drinking water by re-absorbing much of the water from their faeces and producing small amounts of very concentrated urine. Behavioural adaptations are the actions that an animal takes – what it does – to survive, such as migration, resting in the heat of the day or huddling with other individuals to conserve body heat and moisture.
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:
There are several strategies you can use to revise for mid-year exams – here are just a few:
- Use the Hawkesdale Biology Quizlet Class to revise terms and definitions for each chapter
- Copy and revise the Slideshows I have saved in the Year 11 and Year 12 Biology class folders (Student Public Drive)
- Create a set of study notes with the Chapter headings, diagrams and key concepts. These will be very useful at the end of the year for revision too.
- Create mind maps that link each of the main concepts – use colour to help you remember.
- Use the posts in this blog to review YouTube videos and other resources for each chapter.
- Past exams are a good indication of the standard of questions you will be asked – do as many as you can reasonably cope with! Use questions you find difficult as a guide to what you need to study more of.
- Create flow charts and posters for the wall at home of concepts that can be represented diagrammatically.
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:
- Phylum (and sub-phyla)
- Class (and sub-class)
- Order (and sub-order)
Some more resources to learn about classification:
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.
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.
Image from WorldMapper: The world as you’ve never seen it before
This map shows the size of the country in proportion to the absolute number of people that died from infectious and parasitic diseases in one year. Australia, Europe and America are barely visible due to good sanitation practices, education and high quality health care, including vaccination programs. Africa and India are disproportionately large due to HIV/AIDS (27% of total deaths); diarrhoeal diseases (17%); tuberculosis (14%); malaria (8%); measles (6%) and whooping cough (3%).
Infectious diseases have had significant impacts on population numbers, politics and society throughout history, from the Athens epidemic (430-427BC) that killed up to half the population of ancient Athens, waves of plague (‘Black death’) that killed up to 90% of Europeans in the 12th century and smallpox that ravaged populations as the Spanish and Portuguese conquistadors invaded the Americas. (“Early History of Infectious Disease” by Nelson and Williams)
More recently, vaccination programs have been very successful in eradicating smallpox and dramatically reducing the numbers of cases of polio, measles/rubella and tetanus. However, diseases such as HIV/AIDS, various influenza strains and Ebola are still causing many deaths throughout the world. The pathogens that cause these diseases are very good at evading the immune system, making it difficult for the immune system to recognise or remember them.
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
ELISA technique with materials supplied by Zoetis Australia.
This week we had another opportunity to connect with the Gene Technology Access Centre via Polycom. The topic of this session was the Hendra virus and a method to detect antibodies with a colour change (called ELISA – Enzyme-Linked Immuno-Sorbent Assay). We are very grateful to Zoetis for supplying the materials for this practical work and Fran at GTAC for stepping us through the process.
In a suburb of Brisbane in 1994, a horse-trainer and fourteen horses died of a mysterious illness within days of falling ill. CSIRO’s Australian Animal Health Laboratory, in Geelong, swung into action and worked intensively on blood and tissue samples for two weeks before identifying the virus responsible as Equine morbillivirus. However, further genetic analysis showed that the most appropriate classification of the virus was to place it in a new genus within the family Paramyxoviridae. It was later renamed Hendra virus, after the name of the Brisbane suburb in which the original outbreak occurred.
Zoetis Australia is a global animal health company who research and create animal medicines and vaccines, complemented by diagnostics products and genetics tests. As well as a Hendra virus vaccine, they have developed a technique for determining if an animal has virus antibodies present, which indicates that the individual has been exposed to the disease or has been vaccinated previously. We will use this technique to determine if three horses have had prior exposure to the disease or if they need to be vaccinated or receive booster shots.
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: