Classification, Variation, and Inheritance in Organisms

1. Write a definition for these keywords Vertebrate Invertebrate Homeotherm Poikilotherm Viviparous Oviparous Using the zedonk as an example, explain the difference between a species and a hybrid. Characteristics: Suggest two gulls that cannot interbreed. Why aren’t they classified as separate species? What is the binomial naming system and why is it useful? Explain why it was difficult to classify the platypus as a mammal. Suggest how Scientists finally made that decision. (5 marks) Classification, Variation and Inheritance Label the polar bear’s adaptations Calculate the mean length of these seed pods (23mm, 25.5mm, 26mm, 32mm, 34.5mm, 37mm) Describe the two graphs shown below. What type of variation is shown? Give examples. birds How does classification make it easier to measure biodiversity? Why do we need to protect biodiversity hotspots? reptiles mammals

2. Ring species It is difficult to know where to draw the line between one species and the next in the middle of the ring. The platypus, a good answer will contain the following points:  platypuses are like reptiles because they lay leathery eggs  they are like reptiles because they have a skeleton structure/body shape that is like a lizard’s  they are like birds because they have a beak  like all mammals it has hair  like all mammals it produces milk (although, as a point on interest, it doesn’t have nipples)  all mammals produce eggs, it’s just that the eggs tend to stay inside the female to develop They bear more similarities with mammals than with any of the other groups (some students might suggest that DNA testing would show their similarity to other mammals and this should also be given credit, even though DNA analysis was invented long after the classification of platypuses as mammals). Biodiversity hotspots It makes the identification of different species easy and so allows an accurate measure of the numbers of different species in an area (biodiversity), even if some of the species appear quite similar. The hotspots contain greater numbers of species than other areas and so by protecting them you are protecting more species than you could otherwise. Some students may go on to mention the importance of preserving species in general, including possible future uses by humans and that more biodiverse areas are better able to cope with environmental changes.

3. Write definitions for these key words: Evolution Speciation Competition Natural selection What type of chart is this? How and why might doctors use it? Construct a punnet square to show the genotypes of the offspring between a mother who is a Cystic Fibrosis sufferer and father who is a heterozygous non-sufferer. Sickle-cell disease has been a problem in Africa for centuries. Before modern medicine, the disease usually killed people before they were able to have children. So you would expect the allele to quickly be removed from a population of people. Explain why the allele still exists. Show the probability of each phenotype occurring in decimals, % and ratios Write definitions for these key words: Homozygous Heterozygous Dominant Recessive Genotype Phenotype Ground finches have large powerful beaks to crush seeds, a closely related species now has a narrow beak for probing in small holes for insect larvae. Suggest how the newer species could have evolved. Genes and Evolution Hint: sickle cell sufferers cannot catch malaria What is a genetic disorder? Describe the effects of these genetic disorders… Cystic Fibrosis – Sickle Cell disease – Describe how the use of warfarin to kill rats has led to the majority of rats now being resistant to warfarin

4. Sickle cell: Children with one copy of the sickle-cell allele are more likely to survive malaria than those without any sickle-cell alleles. These children are more likely to survive long enough to have their own children and pass on the allele, whilst others will die from malaria. Describe how the use of warfarin to kill rats has led to the majority of rats now being resistant to warfarin Warfarin was used to kill rats in the 1940s, however some rats were naturally resistant to warfarin (it didn’t kill them) due to natural variation within the species. The warfarin killed all the normal rats, but those that were resistant to it survived and passed on the genes for resistance to their offspring. The offspring inherited the genes and were resistant to warfarin too. • Finches: a good answer will contain the following points: • on an island with few seeds (but many insects) • some finches had naturally narrower beaks and were able to reach more insects • these finches survived more often than the ones with larger beaks • the finches with narrower beaks reproduced more often, passing on the genes for narrow beaks • of those finch offspring, those with even narrower beaks were still more likely to be able to get insects • so were more successful and survived and reproduced • this meant that gradually, over time, the birds got narrower and narrower beaks

5. Hot or cold? Label the diagrams to show all the changes that occur to cool you down or warm you up. Why do they happen? You play in the snow for an hour, describe the changes that occur in your body to ensure your core temperature remains at 37°C What is hypothermia? Name and label these neurones What are their functions? Label this diagram of a synapse. Outline the role of the synapse. Whys is it important to have small numbers of these in a reflex arc? Produce a flow chart that illustrates the path along a reflex arc vs Reflex actions What is the function of the myelin sheath? Coordinated responses Write definitions for these key words: Osmoregulation Thermoregulation Homeostasis Negative feedback Homeostasis and Sensitivity What relationships or correlations can you see in this graph? Why? What is the difference between a nerve, a neurone and the CNS? Vasoconstriction Vasodilation

6. Playing in the snow Include the key words: dermis, hypothalamus, erector muscles, vasoconstriction

7. Write definitions for these key words: Target organ Diabetes Subcutaneous fat Phototropism Geotropism Glucagon Glycogen Why are bananas that are grown in Africa over 4000 miles away are perfectly yellow in our shops? What hormone causes plants to grow like this and how does it have this effect? What causes roots & shoots to grow in opposite directions? Which would germinate first; a seed soaked in water, a seed soaked in gibberellins. Can you explain why? How are plant hormones used? Hormones Imagine you are a doctor, how would you explain to a patient the difference between type 1 and 2 diabetes. What treatments would you recommend for each? Control of blood glucose Calculate the BMI of someone who is 1.72m tall and weighs 98kg (show your working) Are they at risk of type 2 diabetes? Why? Messages carried by nerves vs Messages carried by hormones Explain how insulin helps to control blood glucose concentrations. [6 marks] Label these endocrine glands and give their functions

8. insulin made by/released by/secreted from endocrine glands • insulin is a hormone • pancreas makes/releases/secretes insulin • liver is the target organ/where insulin has an effect • insulin is released when blood glucose concentrations go above a certain level • insulin causes glucose removal from the blood so lowering its concentration • glucose from blood is made into glycogen • insulin release is switched off when concentrations fall back into normal range

9. What is this organism and what diseases is it linked to? Why? Cigarette smoke only enters the lungs, explain why smoking can cause diseases all over the body and give examples. Turn this statement into an explanation: Antibiotic resistance is an example of evolution. Explain why you can buy painkillers such as paracetamol in a shop but only a doctor can give you morphine. Label all the ways in which the human body prevents entry of pathogens Drugs and Pathogens Write definitions for these key words: Antiseptic Antibiotic Pathogen Cirrhosis Vector Lysozyme Describe and explain the patterns shown in the graph Use Scientific evidence to put forward an argument for raising the legal age to buy alcohol to 21 GABA is a neurotransmitter that is released at inhibitory synapses, which drugs do you think might increase the release of GABA and why? What criteria do doctors use to decide who gets organ transplants? Why might an athlete be banned from taking part in the Olympics if they had taken cold medicine?

10. Why is there a limit to the length of a food chain? Produce a pyramid of biomass for this food chain Field of corn  Locust Mouse  Snake  Hawk (150g/m2) (60g/m2) (40g/m2) (15g/m2) (8g/m2) What would happen if a disease killed half the mouse population? Write definitions for these words: Consumer Producer Trophic level Biomass Interdependent The Nitrogen Cycle Add labels to this simplified carbon cycle. How could you improve it? Describe how & why you could use lichen to indicate the level of pollution in a given area. How does this model help explain what happens in terms of energy? What doesn’t it show us? How is acid rain formed and what is its effect on the environment? Environment Complete the stages of the nitrogen cycle Describe the ways in which carbon is recycled. Name the organism and describe the relationship it has with others 6 In what ways are tape worms so well adapted to living in their host? 4 Label the diagram to show how Eutrophication occurs 1 What does this graph show? What impact will this have on the environment & why? 2 Give 2 examples of each of the following: Clean water indicator: Polluted water indicator: Air quality indicator: 3 5