The Nervous System: Messages and Control

1. Unit 5

2. B1.2.1 The nervous system The nervous system uses electrical impulses to send messages along neurons. These are VERY fast and allow you to respond quickly to changes in the environment. Neurone – a cell that transmits electrical impulses in the nervous system. Central Nervous system (CNS) – Brain and Spinal cord. Peripheral Nervous system (PNS) - nerves connecting the sense organs and effectors to the CNS Sense organs – detect changes both in and outside your body. They contain receptor cells Eye; Ear; Skin; Mouth; Nose Stimulus – Anything your body is sensitive to e.g. noise, heat, light. Impulses – Electrical signals in the nervous system that travel through neurones. Types of Neurone : Sensory neurones send impulses from receptors in the sense organs to the CNS. Motor neurones send impulses from the CNS to muscles and glands. Relay neurones found in the spinal cord/brain. The link sensory and motor neurones. Light receptor cells, like most animal cells, have a nucleus, cytoplasm and cell membrane. The Reflex Arc – an automatic response A – Receptor (reacts to a stimulus) B – Sensory Neuron (carries message to the co-ordinator/CNS) C – Relay Neuron Gaps between neurons are called SYNAPSES D – Motor Neuron (carries message away from co-ordinator/CNS E – Effector (a muscle or gland)

3. B1.2.2 Control in the human body – Hormones and Homeostasis Hormones: The endocrine system produces hormones in parts of the body called glands. These are chemicals that help control body functions. The glands release the hormones into the blood where they are carried to target organs.Hormones travel a lot slower than nerve messages but their effects are usually longer lasting and they act quickly. Hormones control things like menstruation in women as well as the changes that occur to our bodies during puberty and homeostasis. Factors controlled by homeostasis: Water content– water leaves the body by: lungs when we breathe out, skin when we sweat, kidneys in the urine Ion content– ions are lost by: skin when we sweat, kidneys in the urine Temperature – to maintain the temperature at which enzymes work best for chemical reactions in the cells. Normal body temperature is 37oC Blood glucose levels – controlled by the pancreas to provide the cells with a constant supply of energy. SAS survival manual says to conserve water: - Avoid exercise, stay in the shade, don’t lie on hot ground – no sweating. - Don’t eat – digestion uses up water. - Don’t talk and breathe through your mouth – so no water lost from mouth.

4. Coordination and control • How are messages sent around the body? • Name the 3 neurones? • Which is attached to the receptor? effector? • What is a synapse? CNS? • How is the message different across a synapse? • List the steps in a reflex arc • What is a reflex? • List 2 conscious and 2 unconscious control? • What do plants respond to? What are these response called? • Which parts of the plants respond? • Name the hormone found in plants • How are plant hormones used?

5. 6Mark question Describe in detail what will happen if Cartman’s blow torch touches his fingers (think nervous system)

6. Peer assess • The pain receptors in the finger sense the pain and stimulate the sensory neurone. • Once the sensory neurone has been stimulated an electrical impulse travels along its length to the spinal cord. • The sensory neurone is connected to a relay neurone via a synapse. • The relay neurone is triggered by a chemical messenger which in turn triggers the motor neurone. • This stimulates the effector organ (biceps muscle). • The relay neurone also sends a message to the brain so it knows what is going on

7. B1.2.2 Control in the human body – Menstrual Cycle Controlling fertility: Contraception :Inhibits production of FSH so eggs don't mature in the ovaries. Fertility treatments: FSH used to stimulate eggs to mature and trigger oestrogen production. IVF - eggs collected and fertilised in the lab then implanted Advantages - fewer children (cost), women freedom. Disadvantages - expensive, multiple births, embryo use Menstrual cycle 28 days Reproductive cycle in women. Brought about by hormones. • Womb lining thickens • Eggs released from ovary after 14 days: ovulation • If not fertilised the womb lining and egg come out as a period

8. Coordination and control • What are hormones? • Name the 2 organs and the 4 hormones they produce • Briefly describe their role? • What is ovulation? What day does this happen? • What is contraception? List some methods • List some infertility treatments • What is homeostasis? • How are water and ions maintained? • How is temperature maintained? • How is blood sugar maintained?

9. 6 Mark question Compare nervous impulses and hormone responses, using examples of each response in your answer

10. Peer assess Example Nervous Impulses include: •A response to a stimulus (e.g. hand on a hot pan handle) •A reflex response (e.g. blinking when something approaches your eye Example Hormone Responses include: •Insulin to regulate blood sugar levels •Adrelinto stimulate the flight or fight response •Oestrogen/Progesterone/LH/FSH to control the menstrual cycle •Thyroxin to control the rate of growth

11. Unit 6

12. Genetic information is in the nucleus of cells Inside the nucleus are chromosomes made up of DNA – humans have 46 chromosomes (23 pairs) fruit flies have 8 chromosomes (4 pairs) Genes are a section of DNA and control enzymes and proteins made in our body Genes are passed on to you in the sex cells (gametes) from your parents – they come in pairs B1.7.1 Why organisms are different Genetic Variations: Passed on from parents in your genes E.g. Eye colour, gender, shape of nose Environmental Variations: Due to the way of life E.g. Scars, accents, hair length Combined causes of variations: E.g. Height, weight Investigating variety: scientists study twins adopted by different families compared to identical twins brought up together and non-identical twins.

13. Variation, reproduction and technology • Where is genetic information? • What are chromosomes made of? • What is the structure of DNA? • What is the basic unit for inheritance? • What do genes code for? Why do genes come in pairs? • How many chromosomes in body cells? Gametes? • What is the difference between asexual and sexual reproduction? • Why is variation important? • List 2 ways variation happens and give examples of both. • List 2 factors that are a combination of both of the above

14. Reproduction can be sexual or asexual. Sexual reproduction produces variation. Asexual reproduction produces clones. B1.7.2 Reproduction In sexual reproduction two parents are involved. A mixture of genes is created. This variety is good as it helps us cope with changes and diseases as a species. Occurs in animals and some plants e.g. flowering plants. Advantages – allows evolution, variation, increases chances of species survival Disadvantages – need to find a partner, waste energy. Waste in producing gametes, slower Asexual reproduction involves only one parent. So there is no genetic variety (CLONES). Occurs in bacteria and some plants e.g. strawberries.

15. Variation, reproduction and technology • What is genetic engineering? • List the stages in genetic engineering • Why are bacteria used to produce insulin for humans? • What are the main advantages and disadvantages of genetic engineering? • What is embryo screening? • How is asexual reproduction different to sexual reproduction?

16. 6Mark question Explain how Spiderman was genetically engineered and name the process that will make copies of Spiderman No GaGa, I wasn’t born this way, I was bitten by a genetically engineered spider!

17. Peer assess • Desired gene selected and identified • Gene removed from spider • Using enzymes – restriction enzyme • Human DNA is cut open • Gene from spider is inserted into human DNA • Using ligase enzymes • New gene works in the human

18. Evolution • What is meant by evolution? Natural selection? • What was Darwin's theory? • Where did he travel to on what ? (names)which 3 organism did he find similarities in? • Was why was Darwins theory not accepted at first? What book did he publish? Why did it take so long to publish? • What else is natural selection known as? • What are mutations? How does this affect an organism? • What is speciation? • Wh came up with the theory of speciation?

19. 6Mark question Road runners used to have shorter legs why do you think the current generations have longer legs? Explain as fully as you can.

20. Peer assess • Organisms differ due to variation • Variation is inherited • Caused by mutations • Competition between species • Better adapted survive • Breed and reproduce • Genes passed on to offspring

21. All species of living things alive today have evolved from the first simple life forms. B1.8.1 Evolution- Theories Charles Darwin travelled the Galapago Islands and noticed animals were adapted to their surroundings – his theory is that all living organisms have evolved from simpler life forms. This process has come about by natural selection – accepted theory. Jean-Baptiste Lamarck -French biologist His idea was that every animal evolved from primitive worms - The change was caused by the inheritance of acquired characteristics Problems with Lamarck: No evidence - People didn’t like to think they descended from worms - People could see clearly that changes were not passed onto their children (e.g. Big muscles) Why did people object? Religious – god made the world Not enough evidence No way to explain inheritance – genetics not known about It took 50 years after Darwin’s theory was published to discover how inheritance and variation worked

22. B1.8.1 Evolution- Classification Biologists classify living organisms according to how closely they are related to one another. Similarities and differences Different organisms can be classified by studying their similarities and differences. These studies also help us to understand the evolutionary relationships between different organisms. Species: A group of similar organisms that can breed to produce fertile offspring Evolutionary tree DNA evidence used to decide which species an animal belongs to and work out evolutionary relationships Darwin’s theory of Evolution by Natural Selection Variation –populations of organisms have variations. Over-production –produce more young than will survive to adulthood. Struggle for existence – competition for survival between the organisms Survival – those with advantageous characteristics are more likely to survive Advantageous characteristics inherited – better adapted organisms are more likely to Reproduce successfully passing on the advantageous characteristics to their offspring in their genes. Gradual change – over a period of time the more individuals with the advantageous characteristics in the population. New evidence from DNA research and the emergence of resistant organisms supports Darwin’s theory

23. Evolution • What is classification? • Who came up with the old classification system? The new one? • How are organisms classified? • What are the 3 domains? • Which is the biggest and smallest group of classification? • Name the 5 biggest groups? • What do we call evolutionary links between organisms? • How are they useful? • What’s the difference between an evolutionary and ecological relationship? • What is the binomial system?

24. What are the female chromosomes? Males? • Draw a genetic cross for having a boy or a girl • What are dominant characteristics? Recessive? Give examples • Define genotype, phenotype, heterozygous, homozygous • What is a genetic disorder? • Describe the symptoms and inheritance of polydactyl and cystic fibrosis. Draw punnet squares to show how they can be inherited. • What are carriers? Why must both of your parents be carriers to inherit cystic fibrosis? Where as polydactyl you only need one parent to inherit it

25. 6 Mark question

26. Peer assess

27. Old and new species • What are fossils? • What can we learn from fossils? • How can fossils be formed? • Why is the fossil record incomplete? • Which animal has a complete fossil record? • Why is it difficult for scientists to know exactly how long ago life on earth began? • What is extinction? List ways that organisms cause extinction • What environmental changes cause extinction? • Give 2 possible causes of mass extinction

28. 6 Mark question Define extinction and explain how a species can become extinct.

29. Peer assess • When a species no longer exists • Environmental change • Habitat loss • Competition • Predators • Disease • Catastrophic event

30. 6 Mark question New species can arise from existing species. This is called speciation. Explain how speciation can occur.

31. Peer assess • New species arise as a result of: • isolation – two populations of a species become separated, eg geographically • genetic variation – each population has a wide range of alleles that control their characteristics • natural selection – in each population, the alleles that control the characteristics which help the organism to survive are selected • speciation – the populations become so different that successful interbreeding is no longer possible.

32. Unit 7

33. Adaptation for survival • What do plants compete for? animals? • What is intra specific competition? Interspecific competition? • List some plant adaptations to avoid competition? • How are seeds spread to avoid competition? 3 ways • What affects the distribution of species? • Give examples of living and non living environmental factors • What is distribution? • How can environmental change be measured? • How do changes in the environment affect distribution? • List the main causes for the decline of the bumble bee

34. Living organisms need to survive and reproduce • Plantsneed: light, carbon dioxide, water, oxygen, nutrients • Animalsneed: food, water, shelter, mates, territory • Microorganisms needs depend - some are light plants, some like animals and some need no oxygen or light B1.4.1 Adaptations Animal survival Surface area: volume ratio Mammals in a cool climate grow to a large size (e.g. Whales) to keep their ratio as small as possible to maintain body heat Being the most competitive means an organism will be more likely to survive and pass its genes on to its offspring Remember: Plants have adaptations too. They need light, water and space with nutrients to grow. Dry climates Deserts may be hot in day and freezing at night. Lack of water. Often active at night rather than day. Can’t sweat or will lose water. Large surface area:volume to lose heat through skin. Big ears- lose heat. Thin fur, little body fat Camouflage : Important in predators and prey Dependent on environment (arctic hares brown in summer and white in winter) Cold Climates: Small surface area:volumee.g. Ears. Insulation – blubber (thick layer of fat under skin), fur coat Fat layer also provides a food supply during winter) Extremophiles have adaptations for living in extreme conditions. Such as high heat and pressures e.g. deep ocean volcanoes!

35. Adaptation for survival • What do animals, Plant, Microorganisms need to survive and reproduce • What is the difference between herbivores and carnivores teeth? • Define what an extremophile is • Why are bacteria able to live in high temperatures? • Give another example of an extremophile adaptation • List adaptations of plants and animals living in hot conditions • List adaptations of living in a cold climate • List 3 ways plants reduce water loss in hot and dry climates • Where can a plant store water?

36. 6 Mark question Plants and animals have become adapted in many different ways to reduce the risk of being eaten by predators.

37. Peer assess

38. As environmental changes happen the distribution of organisms also changes. We can collect information on these changes but it is difficult to do it a way that can be repeated by others making it difficult to draw conclusion and say why the change has happened. B1.4.2 Environmental change Changes in an environment can be measured by looking at living indicators (Mosses and Lichens) These are very sensitive to changes in AIR pollution. Water pollution: harmful substances into rivers, lakes etc. Some invertebrate animals cannot survive in polluted water their presence or absence shows if water is polluted. The environment can change due living factors like a new predator or disease or a non-living factor like a temperature rise or lack of sun and water. Environmental changes can be measured using non-living indicators such as oxygen/CO2 levels, temperature and rainfall. Bees Disease (CCD) affecting honey bees Bees are important for pollination of plants – apples, raspberries, cucumbers etc Cause unknown – pesticides? Climate?

39. List the 6 physical factors that affect living organisms living in an environment • How can the distribution of organisms be measured? • Explain how a quadrat is used • How is a transect used? • What is validity? Reproducibility? • Why is sample size important • What are control variables? Independent variable? Dependent variable?

40. B4 Mark question Describe how you would use a 1/2-metre x 1/2-metre quadrat frame and a 30-metre tape measure to obtain data on plant distribution along a transect line. You should include details of how you would make sure that you would obtain valid results.

41. Peer assess • 1-2 marks • There is a basic description of how a quadrat or a meter tape could be used to collect data. Poor SPAG. • 3-4 marks • There is a clear description of how a quadrat and a metre tape could be used to collect • data along a line. Some SPAG Errors. • 5-6 marks • There is a clear, logical and detailed description of a method that will produce valid, repeatable results at intervals along the chosen sample area. Almost faultless SPAG. • Use a tape measure to produce a transect along the sample area, i.e a stream. • Place the quadrat at regular intervals along the tape and count each plant species inside the quadrat. Repeat the transect several times at random or regular intervals along the stream.

42. Trophic level – organisms that feed at the same level Interdependence – organisms in an area that depend on each other Dynamic relationship – constantly changing populations B1.5.1 Energy in biomass Energy that will become part of the animals biomass Plants are producers . They are always at the start of food chains, pyramids of numbers and pyramids of biomass. Carnivores, top predators 1110 KJ in heat loss Carnivores, both predator and prey Herbivores Biomass is the dry mass of living material in an animal or plant. Plants Pyramid of Biomass. The biomass of each organism in a food chain. Labelled layer for each thing in your food chain The producer is always the biggest layer and it is always pyramid shaped. Pyramids of numbers just tell you how many of each organism you have in each step of the food chain. Not about the energy being passed on. They don’t have to be pyramid shaped. 3060 KJ in food 1797 KJ in urine and faeces

43. Energy in biomass • What is biomass? • What is the original source of energy in a food chain? • What does a food chain always start with? • Draw a pyramid of biomass and a pyramid of numbers for oak tree, aphids, ladybirds, label the producer, primary and secondary consumer • Why does it get smaller as it gets to the top? • How is energy lost? • Why do mammals and birds transfer more energy? • Why do carnivores eat less and less often?

44. Detritivores – worms and maggots that feed on dead materialDecomposer – organisms (bacteria and fungi) that feeds on dead material starting the process of decay B1.6.2 The carbon cycle The amount of carbon is fixed Carbon is recycled as carbon dioxide (CO2) through respiration and photosynthesis. Photosynthesis: green plants and algae remove CO2 from the atmosphere – passed on when plants are eaten. Plants use CO2 to make carbohydrates, fats and proteins. Carbon dioxide + water  glucose + oxygen Respiration: living organisms use oxygen to break down glucose CO2 is a waste product. Decomposers respire too Glucose + oxygen  carbon dioxide + water Combustion: fossil fuels contain carbon , when we burn then CO2 is produced Fuel + oxygen  carbon dioxide + water Chalk and some other sedimentary rocks is formed from the fossilised remains of sea creatures. When these rocks are exposed to rain (which is slightly acid), the rock dissolves and more CO2 is released.

45. Energy in biomass • How is CO2 added to the environment? • List the word equations for combustion, photosynthesis and respiration • Describe the carbon cycle • What do plants use the CO2 to create? • How does this get into animals? • List the steps in the water cycle? • What is biodiversity? • How can we conserve organisms? • Why are peat bogs important? • List reasons for deforestation • What causes global warming