AQA Combined Higher Science - Biology Paper 2 Notes

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received by other neurons Adaptations include Insulated by a fatty sheath, long so can carry messages throughout the body Dendrite branches of neurons that receive signals from other neurons Regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in repones to internal and external changes. The mechanism that reverses a change Rapid and automatic response to a stimulus Change in a environment Spec Point / Questions Key Terms Effector Coordination centres Receptors Notes A synapse is a gap between the two neurons In which chemicals diffuse across 1. An electrical impulse travel along the first axon 2. Which triggers the nerve-ending of a neutron to release neurotransmitters A neurotransmitter is a chemical involved in passing nerve impulses 3. 4. These chemicals diffuse across the synapse (gap) and bind with receptor molecules on the membrane of the second neuron. 5. The receptor molecules on the second neurneurond p only to specific neuronthe second neuroneuronransmit electrical impulses The central nervous system receives and processes information from receptors (made up of brain and spinal cords) 1. Information from receptors passes along sensory neurons as electrical impulses to the CNS 2. Repones of effectors include muscles or glands secreting hormones Stimulus → receptor → sensory neuron Motor neuroneneuronctor Reflexes is a rapid repones to certain stimuli that don't involve the conscious part of the body 1. Receptorss in skin dethe tects stimuli (change in temp) 2. Setempsoneurone sends electrical impulses to relay neurone in the CNS 3. Motor neurone sends electrical impulses to a effector 4. Effector produces response Required Practical 7- Investigating reaction time Reacting time is the time it takes to respond to a stimulus affected by many factors 1. Person being tested should sit with their arm rested on the edge of the table Hold a ruler vertically between their farm and forefinger. Make sure the zero end of the ruler is level with the thumb and finger, then let go with no 2. 3. 4. warning. Person being tested should try and catch the ruler. Reaction time is measured on the ruler where it's caught, The further down, the slower the reaction time. 5. Repeat the test several times and calculate the mean. Control variable is. Same person catching ruler each time. Same hand to catch the ruler. Same height that the rulers dropped from. Measuring reaction time using a computer. Gives more precise reaction times as they remove the possibility of human error. Is more accurate reaction times as the recorder in milliseconds also. Muscles / glands which bring responses which restore optimal levels. Areas of the body like the brain, spinal cord, pancreas that recive that process information from the receptors Organs or cell that detect stimuli Spec Point / Questions 4.5.3.1 Human endocrine system 4.5.3.2 Control of blood glucose conc Key Terms Notes Endocrine system is a group of glands which secrete chemicals called hormones directly into the bloodstream The blood carries the hormone to the target organ where it produces and effect Compared to the nervous system, the action is slower but acts for longer Pituitary gland is known as the master gland because it releases hormones which control the release of other hormones - such as Pancreas releases the hormones insulin and glucagon which control blood glucose levels Thyroid-releases thyroxine which controls metabolism and is involved in maintaining body temperature and heart rate Adrenal gland - releases adrenaline causing changes in the body such as increased breathing rate, blood glucose, blood flow and dilated pupil Ovary - releases oestrogen involved in the menstrual cycle Testes-releases testosterone which controls sperm production Pancreas releases the hormone insulin and glycogen which control blood glucose level. Excess glucose is stored as glycogen. If blood glucose level is too low than glucagon is added. 1. Blood with too little glucose 2. Glucagon is secreted by pancreas 3. Glycogen makes live turn glycogen into glucose 4. Glucose released into blood by live If blood glucose level is too high, then insulin is added 1. Blood with too much glucose 2. Insulin secreted by pancreas 3. Causing glucose to move from blood to cells 4. Insulin makes live turn glucose into glycogen 5. Glucose moves from blood to muscle Diabetes is a condition which affects the ability to control blood sugar levels Type 1 diabetes is when the pancreas produces little or no insulin Meaning that a persons blood glucose level can rise and kill them Requires insulin therapy involving several injections of insulin after meals To make sure that glucose is removed one the food has been digested Can be controlled by diet, more activeness, limiting food intake, regular exercise Type 2 diabetes is a person becoming resistant to their own insulin due to being overweight Meaning that a person blood glucose level can rise and kill them Can be controlled by obesity, diet, exercise Spec Point / Questions 4.5.3.4 Hormones in human reproduction 4.5.3.5 Contraception Key Terms Notes Testosterone is the main reproductive hormone in men. It is produced by the tested and stimulates sperm production. Oestrogen is the main reproductive hormone in women. It is produced by the ovaries and is involved in the menstrual cycle. Steps of the menstrual cycle include. 1. Lining if uterus breaks down. 2. Lining of uterus builds up again into a thick spongy layer full of blood vessels, ready to receive a egg. Egg develops and is released - called ovulation. If no fertilised egg has langed on the uterus by day 28, the spongy lining breaks down. Four hormones that control the cycle are FSH → Oestrogen → LH → Progesterone. ■ FSH is produced in pituitary gland. ■Causes an egg to mature in one of the ovaries (follicle) Stimulates the ovaries to produce oestrogen. 3. 4. Oestrogen is produced in the ovaries. Causes the lining of the uterus to grow. Stimulates the release of LH and inhibits release of FSH Contraception is a method to prevent fertilisation of any egg by sperm Oestrogen can be used to prevent the release of an egg, it inhibits the production of FSH and egg development Progesterone reduces fertility by stimulating the production of thick mucus to prevent any sperm from reaching an egg Oral contraceptives are certain hormones to inhibit FSH production so that no eggs mature. Injection, implant, or ski patch release progesterone slowly to inhibit the maturation and release of eggs. Barrier methods like condoms prevent sperm from reaching the egg Intrauterine device prevents egg from implanting in the uterine lining Spermicidal agents kill or disable the sperm. Surgical methods of female or male sterilisation such as vasectomy Spec Point / Questions 4.5.3.6 Use of hormones to Key Terms treat infertility 4.5.3.7 Negative Feedback Notes Fertility drugs is medication which enhances reproductive fertility FSH and LH can be given to women to stimulate ovulation Doesn't always work so has to be repeated and can be expensive Too many eggs can be stimulated resulting in unexpected multiple pregnancies It can be stressful, expensive, low success rate, chance of twins, could lead to a selection of characteristics In Vitro fertilisation is the process of fertilisation In a lab IVF involves giving a mother FSH and LH to stimulate the maturation of several eggs The eggs are collected from the mother and fertilised by sperm from the father in the lab The fertilised eggs develop into embryos At the stage when they are tiny balls of cell, one or two embryos are inserted into the mothers womb Adrenaline is a hormone released by adrenal glands in response to stressful situations. Increases supply of oxygen and glucose to cells in the brains and muscles Increases heart rate preparing the body for flight or fight. Thyroxine is produced by the thyroid glands and stimulates the basal metabolic rate. Plays an important role in grown and development Regulates base metabolic rate the speed at which chemical reactions occur during rest Important for protein synthesis Levels of thyroxine are controlled by negative feedback Spec Point / Questions Notes 1. Define homoeostasis. Maintance of a constant internal environment 2. What does the brain do in homeostasis? control centre of everything 3. What does central nervous system do in homeostasis? controls heart rate, breathing, digestive system 4. What is the endocrine system? Collection of glands which release hormones to 5. Where is the pituitary gland? 6. Where is the pancreas? Behind the stomach 7. Where is the thyroid? neck 8. Where is the adrenal gland? kidneys 9. Where are the ovaries? Halfway btwn belly button and hips 10. Where are the testis? Ur penis 11. How is blood glucose monitored? Liver and insulin 12. What happens when blood glucose is too high? Liver converts it into glucagon 13. What is the menstrual cycle? Build up and release of blood in uterus 14. What is ovulation? Egg is released 15. What is testosterone? Hormone in men 16. What is contraception? Block baby ting u know 17. What happens when blood glucose is too low? Liver glycogen into glucose 18. What is a negative feedback loop? Reaction causses decrease in reaction 19. What is FSH? Follicle stimulated hormone. 20. What is LH? Luteinising Hormone 21. What is oestrogen? Female hormone responsible for mensturual cycle 22. Where is FSH produced? Pitual glands 23. Where does FSH act? Acts on egg and causes it to mature Video Title: Topic 6- Inheritance Spec Point / Questions 4.6.1.1 Sexual & Asexual reproduction 4.6.1.2 Meiosis 4.6.1.4 DNA and the Genome Key Terms Notes Gametes is the male and female sex cells (sperm and egg) Only contain one copy of each chromosome. Meiosis is the process where the gametes are formed. 4 different daughter cells whilst mitosis is two. Reproduction is the production of a offspring. Topic/SLR: Topic 6- Inheritance Notion + Spec Notes Asexual reproduction involves only one parent and no fusion of gametes and leads to genetically identical clones using mitosis. Sexual reproduction is the mixing of genetic material involving the fusion of male and female gametes which leads to variety using meiosis. Sperm and egg cells in animals Pollen and egg cells in flowering plants O O Meiosis is the type of cell division which produces gametes for sexual reproduction. Cells in reproductive organs divide by meiosis to form gametes. Gametes join at fertilisation to restore the normal number of chromosomes. The new cell divides by mitosis and the number of cells increase. As the embryo develops, cells differentiate. When a cell divides to form gametes, O Copies of the genetic information are made. The cell divides twice to form 4 gametes, each with a single set of chromosomes. O all gametes are genetically different from each other. O A chromosome is a long molecule of DNA. DNA STRAND A gene is a small section of DNA on a chromosome, each gene codes for a particular sequence of amino acids, to make a specific protein. DNA is a polymer made of two strands forming a double helix and is contained in structures called chromosomes. DNA DOUBLE HELIX DOC A CHROMOSOME (A LONG STRAND OF DNA WRAPPED AROUND PROTEINS) NUCLEUS CONTAINS CHROMOSOMES Genome is the entire genetic material of an organism which has helped to. Search for genes linked to different types of diseases. Understand and treat inherited diseases. Trace human migration patterns from the past Video Title: Spec Point / Questions 4.6.1.6 Genetic inheritance Punnett Square Key Terms Notes Allele is different versions of a particular gene. Dominant means a dominant allele is always expressed, even with only one copy. Recessive is a recessive allele is only expressed with two copies present Homozygous is if the two alleles are present at the same time Heterozygous is if the two alleles present are different You have two alleles of every gene in the body. One on each chromosome in a pair Topic/SLR: Inheritance is the process where genetic formation is passed from parent to child Genotype is the combination of alleles that control each characteristic. Phenotype is the observable characteristics of an organism Most phenotype features are the result of multiple genes and rather than single genes In genetic cross diagrams Dominant alleles are capital letters Recessive alleles are same letter in case IN GENETIC CROSS DIAGRAMS - DOMINANT ALLELES ARE REPRESENTED BY CAPITAL LETTERS RECESSIVE ALLELES ARE REPRESENTED BY THE SAME LETTER IN LOWER CASE KEY T-TALL IDOMINANT) t=SHORT (RECESSIVE) PARENTAL GENOTYPE GAMETES T t TALL T₁ Tt x tt 1/2 CHANCE OF TALL TALL PHENOTYPE T t Tt tt Tt (tt SHORT PARENTAL TGENOTYPE OFFSPRING OFFSPRING GENOTYPES PHENOTYPES Tt TALL SHORT 1/2 CHANCE OF SHORT PHENOTYPE M SHORT lower Video Title: Spec Point / Questions 4.6.1.7 Inherited Disorders 4.6.1.8 Sex Determination 4.6.2.1 Variation Key Terms Notes Some disorders are inherited and can be caused by certain alleles. Topic/SLR: Polydactyly is caused by a dominant allele and means having extra fingers / toes. O People who are heterozygous will be affected as it only requires the dominant allele. Cystic fibrosis is caused by a recessive allele and means a disorder of cell membranes. Results in the body producing large amounts of Sticky mucus in the airways. O O People who are heterozygous won't be affected but may be carriers. Embryo screening is a procedure to analyse an embryo genes before the implant Advantages include - Can avoid suffering by stopping children with genetic disorders. Laws to stop parents from selecting desired characteristics Disadvantages include- Costs a lot of money Gene therapy is a process where normal alleles are inserted into the chromosome of an individual who carries defective alleles Some believe it is unnatural Some believe it helps suffering Ordinary human body cells contain 23 pairs of chromosomes 22 pairs control characteristics. One pair carry the genes that determine the sex In females, the sex chromosomes are the same XX In males, the chromosomes are different XY Variation is the differences in the characteristics of individuals in a population There is usually extensive genetic variation within a population All variants arise from mutations and most have no effect on phenotype If the new phenotype is suited to a environmental change, it can lead to a rapid change in the species Video Title: Spec Point / Questions 4.6.2.2. Evolution 4.6.2.3 Selective Breeding Key Terms Notes Variation can be due to Topic/SLR: The genes they have inherited (genetic cause) The conditions in which they were developed (nurture) Combination of nurture and genetic cause Evolution is the change in inherited characteristics over time through a process of natural selection which may result in forming new species Theory of evolution by natural selection states that all species of living things have evolved from simple life forms that first developed 3 billion yrs ago. If 2 populations of one species become so different in phenotype that they cant interbreed to produce fertile offspring, they have formed two new species Natural selection is a process where organisms better adaptated to their environment tend to survive Individuals in a species show a wide range of variation due to differences in their genes Individuals with characteristics most suited to their environment are more likely to survive and reproduce passing on their genes The individuals that are less well adapted are less likely to survive and reproduce, so are less likely to pass on their genes Over time, characteristics become more common in the population and the species change. Selective breeding is the process by which humans breed plants and animals for genetic characteristics. 1. Choosing parents with the desired characteristics which are bred together 2. From the offspring, those with the desired characteristics are bred together 3. This continues over many generations until all offspring show the desired characteristic This characteristic can be chosen for usefulness / appearance Disease resistance in food crops Animals which produce more meat or milk Domestic dogs with a gentle nature Large interesting flowers Video Title: Spec Point / Questions 4.6.2.4 Genetic Engineering Key Terms Notes Disadvantages Reduction of the gene pool More prone to genetic defects In a new disease appears, as there's not much variation, the others will dies. Selective breeding can lead to inbreeding where some breeds are prone to disease. Topic/SLR: Is the process which involves modifying the genome of a organism by introducing a gene from another organism to give a desired characteristic 1. Restriction enzymes are used to isolate the required gene. This gene is then inserted into a vector, usually a bacterial plasmid or virus The vector is used to insert the gene into the required cells Genes are transferred to the cells of animals, plants or microorganisms so that they develop with the desired characteristic Example include 2. 3. Bacteria being able to produce human insulin to treat diabetes Genetically modified crops having their genes modified to improve size / quality Sheep have been genetically engineered to produce substances like drugs, in their milk to treat diseases Advantages include Reduced use of chemicals like pesticides which help environment Cheaper / less time consuming Disadvantages include Increased costs of seeds Reduced biodiversity of plants Video Title: Spec Point / Questions 4.6.3.4 Evidence for evolution 4.6.3.5 Fossil 4.6.3.6 Extinction Key Terms Notes Topic/SLR: Theory for evolution by natural selection is Widely accepted Evidence for the Darwin theory is now available as It has been shown that characteristics are passed on to offspring in genes there is now further evidence in the fossil record and the knowledge of how resistance to antibiotics evolves in bacteria. Fossils are the remains of a organism from millions of years ago and are found in rocks Fossils may be formed From parts of organisms have not yet decayed because one or more of the conditions needed for decay are absent. When parts of the Organism are replaced by minerals as they decay. As preserved traces of organisms, such as footprints, Burrows and rootlet traces. Many early forms of life were soft bodied, which means that they have left few traces behind. What traces there have been mainly destroyed by geological activity. This is why scientists can't be certain about how life began. We learn from fossils how much how or little different organisms have changed as life developed on earth Extinction occur when there are no remaining individuals of a species still alive Due to New diseases O A species that has not had to evolve resistance to a disease may not have any resistant alleles within the population. O Leading to large numbers of the species dying New predators O A species that has not had to evolve defence mechanisms to a predator will be vulnerable o Leading to species being heavily predated New competitor species O Species will have to complete for resources Changes to the environment O A species may not be well adapted to this change O Like climate change. Some species wont be able to handle it Video Title: Spec Point / Questions 4.6.3.7 Resistant Bacteria Key Terms Notes Topic/SLR: Bacteria can evolve rapidly because they reproduce at a very fast rate. Mutations of bacterial pathogens produce new strains. Some strains might be resistant to antibiotics, and so aren't killed. they survive and reproduce, so the population of the resistant strain rises. the resistance strain will then spread because people are not being mean to it and there is no effective treatment. MRSA is resistant to antibiotics To reduce the rate of development of antibiotic resistant strains - Doctors shouldn't prescribe antibiotics inappropriately, such as treating non serious whatnot Patients should complete their course of antibiotics so all bacteria are killed and non survive to mutate them and form resistant strains The agricultural use should be restricted The development of new antibiotics is costly and slow. It is unlikely to keep up with the emergence of new strains Video Title: Spec Point / Questions 4.6.4 Classification of living organism Key Terms Topic/SLR: Notes Living things have been classified depending on their structure and characteristics in a system developed by a man called Carl Linnaeus It classified living things into kingdom, phylum, class, order, genus, and species. Organisms are named by the binomial system of genus and species. Three domain system - biological classification that divides all living creatures into three groups. 1. Archaea- primitive bacteria often found in extreme environments. 2. Bacteria - true bacteria 3. Euaryota- range of organisms including fungi, animals and protists Naming groups Named organisms in Latin using the binomial system Name of an organism is made up of two parts starting with the genus and followed by the species. Evolutionary trees - methods used by scientists to show how they believe organisms are related Organisms share features because they originally come from a common ancestor. The more similar the base sequences in the DNA of the two species, the more closely related those species are Video Title: Topic 7 - ecology Spec Point / Questions 4.7.1.1 Communities 4.7.1.2 Abiotic factors 4.7.1.3 Biotic factors Key Terms Notes Topic/SLR: An ecosystem is a interaction of a community of living organisms (biotic) with the non-living organisms (abiotic) parts of the environment Individual organism is a single member of a species Population is a number of individuals of the same species living in the same area at the same time A community is multiple populations (of different organisms) living in a habitat A habitat is the place where an organism lives. A competition is the interaction between organisms or species in which both require a resource that is in limited supply O Plants often compete with each other for light and space O Animals often compete with each other for food and mates Interdependence is where all organisms in an ecosystem depend on each other If one species ir removed, it can affect the whole population A stable community is one where all the species and environmental factors are in balance so that the population remains constant. Abiotic means not from living organisms Light intensity affects the rate of photosynthesis Temperature affects the rate of photosynthesis Moisture levels is when plants and animals need water to survive Soil pH and mineral contents is when different species of plants need different levels Wind intensity and direction affects transpiration rates and rate of photosynthesis Carbon dioxide levels is required for photosynthesis Oxygen levels is when some aquatic animals need oxygen to survive. Biotic means from living organisms Availability of food - more food means organisms have higher change to reproduce New predators - could cause a decrease in prey population New pathogens - means the population living will have no immunity or resistance Competition - if two species compete for the same resource and one is better adapted to its environment, then that species will outcompete the other Video Title: Spec Point / Questions 4.7.1.4 Adaptations 4.7.2.1 Levels of organisation Key Terms Notes Adaptation is the biological mechanism where organisms adjust to new environments or changes in their current environment and can be Structural where a physical part or feature of an organism eg - a white fur coat for camouflage Behavioural - the way an organism behaves The functional - biological process within the organism Cold regions Topic/SLR: Small surface area: volume ratio to minimise heat loss Thick fat layer/fur to insulate cold Hot regions Specially adapted kidneys to produce concentrated urine Only active at night Increasing surface area: volume ratio to help the heat loss. Extremophiles - organisms that live in extreme conditions Like high temp, high pressure Producers - organisms that make their food Predators - consumers that kill and eat other animals Prey - organisms are eaten by predators In a stable community, the number of predators/prey fall and rise in cycles Biomass - total mass of living organisms They can photosynthesise and use the glucose to produce other biological molecules, which then make up the producer's biomass Food chains show the transfer of energy between Producer food chains start here Primary consumer - producers are always eaten by primary consumers Secondary consumer - primary consumers are eaten by secondary consumers Tertiary consumers - secondary consumers are eaten by tertiary consumers. Ecology - branch of biology that studies the distribution and abundance of species, the interaction between species and the interaction between species ant their abiotic environment Video Title: Spec Point / Questions 4.7.2.2 How materials are cycled Notes Topic/SLR: Quadrat- square frame made from wood or wire The quadrat is placed at random locations in the area Count the number of organisms in the quadrat. Population size = total area/area sampled X number of organisms sample Transect - line A quadrat is placed at regular places along the transect At each point, the number of organisms are counted in each quadrat KEY 4. Drains back into the sea and the process starts again PEAK IN SHOWSHOE THAR NUMBERS.. --SNOWSHOE HARE -FOLLOWED BY A PEAK IN CANADIAN LYNX NUMBERS. --CANADIAN LYNX The number of predators increases as there is more prey available The number of prey then decreases as there are now more predators The number of predators decreases as there is now less prey available The number of prey increases as there are now fewer predators The cycle now repeate in a Carbon cycle Basically returns carbon from organisms to the atmosphere as carbon dioxide can be used by plants in photosynthesis 1. Carbon is removed from the atmosphere by green plants and algea during photosynthesis. The carbon is used to make glucose, which can be turned into carbohydrates, fats and proteins which make the bodies of plants and algea 2. When plants and algea respire, some carbon is returned to the atmosphere 3. When the plants are eaten by animals, some carbon becomes part of the fats and proteins in their bodies 4. When the animals respire, some carbon is retuned to the atmosphere 5. When plants and animals die, other animals and microorganisms feed on their remains. When these organisms respire, carbon is returned to the atmosphere 6. Animals also produce waste that is broken down 7. Combustion of wood and fossil fuels releases carbon back into the air Water cycle 1. Energy from the sun evaporates water from the land and sea and turns it into water vapour, which also comes from transpiration in plants 2. Warm water vapour is carried upwards and when it gets higher up, it cools and condenses to make clouds 3. Water falls from the clouds as precipitation onto land and provides fresh water Video Title: Spec Point / Questions 4.7.2.4 Impact of environmental change 4.7.3.1 Biodi versit у 4.7.3.2 Waste Management Key Terms Notes Environmental change affect the distribution of species in a ecosystem and changes include Temperature Water Topic/SLR: Distribution of bird species in Germany changes whole time because average temp rise Atmospheric gases - All organisms need water Oxygen is needed for aerobic respiration Some aquatic animals can only survive in water with high oxygen temperatures Carbon dioxide is needed for photosynthesis concentration Biodiversity is the variety of all the different species of organisms on earth, or within a ecosystem A great biodiversity makes sure and stabilises the ecosystem by reducing the dependence of one species on another food, shelter and maintenance of the physical environment. The future of human species on earth relies on us maintaining a good level of biodiversity and many human activities are reducing biodiversity and recently, measures have been input to try and stop this. Producing Waste- destruction of habitats to make space for landfill and toxic chemicals from landfill waste Deforestation - destroying forest habitats that have a high biodiversity Global warming - disrupting ecosystems and reducing biodiversity Rapid growth of the human population and increase in standard of living results in more resources used and more waste produced. Unless waste / chemical materials are properly handled, more pollution will be caused Pollution can occur In water, from sewage, fertiliser, toxic chemicals. In air, from smoke and acidic gases On land, from landfill and from toxic chemicals Pollution kills plants and reduces biodiversity. Video Title: Spec Point / Questions 4.7.3.2 Land Use 4.7.3.4 Deforestation 4.7.3.5 Global Warming Key Terms Notes Topic/SLR: Humans reduce the amount of land available for other animals and plants by building, quarrying, farming and dumping waste. Bogs - areas of land that are waterlogged / acidic - plants living in bogs don't decay fully when they die due to a lack of oxygen. Peat bogs are dense wetlands filled with partially decayed vegetation. The destruction of peat bogs and other areas of peat to produce garden compost, reduces the area of this habitat and the variety of different plant, animal and microorganism species that live there The decay or burning of the peat releases carbon dioxide into the atmosphere Deforestation is the clearing of forest lands Large scale deforestation has occur to Provide land for cattle Grow crops for biofuels Global warming is the long term shift in temperature and weather patterns A greenhouse gas is a gas that absorbs infrared radiation from the sun so it remains trapped in the earth's atmosphere Human activities have led to increasing levels of carbon dioxide and methane in the atmosphere Carbon dioxide is produced during the combustion of fossil fuel Methane is produced by cattle as they digest grass The consequences of global warming due to a enhanced greenhouse effect include Ocean temperature rising - causing ice caps to melt, rising sea levels Increased temperatures - causing extreme weather Changes in / loss or habitats - due to the extreme weather events Decrease in biodiversity - as the food chain is disrupted Video Title: Spec Point / Questions 4.7.3.6 Maintaining Biodiversity Key Terms Notes Topic/SLR: Scientists and concerned people have put in place measures to reduce the effect of humans on ecosystems and biodiversity Breeding programmes for endangered species Protection and regeneration of rare habitats Reintroduction of field margins and hedgerows (clear lines on the field when you look on google maps) Reducing deforestation Recycling rather than dumping in landfill Can be expensive Land that is protected to maintain biodiversity could be instead used for forming and can cause conflict in areas of food shortages Sometimes, organisms are seen as a threat to farmers (like locusts) and can kill crops. This makes a negative effect on the food chain and can cause conflict when species that are already under threat due to hunting