Spain 2º ESO Biology and Geology
Chapters: 8
1. Scientific project
Scientific hypotheses and questions · Searching and communicating science · Reliable scientific sources · Experiments and fieldwork · Modelling natural processes · Observing and collecting data · Analysing results · Scientists and their work
- The Scientific Method – The scientific method is the careful way scientists find out how the world works. Observe something, ask a testable question, make a hypothesis (a clear, testable guess), test it with a fair experiment (change one variable, measure one, keep the rest the same), repeat and record data, analyse it, draw a conclusion and share it so others can check. Results that fail the test are useful too: they send you back to a new hypothesis.
- Research Skills: From a Question to a Finished Project – Research is a careful way of finding an answer. You ask a clear, focused question, plan how to answer it, find information and check that each source can be trusted, collect and analyse your own data, draw a conclusion that the evidence supports, and share it while crediting every source you used.
- Computer Simulation – A model is a simplified description of a real system that keeps only what matters. A computer simulation runs that model step by step in time to see what would happen. It has variables (the state), rules (how the state changes), parameters (numbers we can set) and often randomness, so we repeat runs and average. We check a simulation against real data (validation). Simulations are used for weather, traffic, disease spread, flight training and design, because they are cheaper, safer and faster than real tests, but they are only as good as their model and data.
- Collection of Data: Primary and Secondary Sources, Sampling, Census of India and NSSO – Data can be primary (collected first-hand by you) or secondary (already collected by someone else). Primary data comes from personal interviews, mailed questionnaires or telephone interviews. We may study everyone (census) or a small part (sample). Samples can be random or non-random. Results can have sampling errors and non-sampling errors. In India, the Census counts everyone every 10 years, and the NSSO (now NSO) runs sample surveys.
- Data: Source and Compilation (Class 12 Geography Practical) – Data are numbers or facts about places and people. We get them from primary sources (our own field work), secondary sources (published by others) and unpublished records. Raw data are messy, so we tabulate them in a clear table, group them into equal classes and count the frequency of each class. A frequency polygon joins the midpoints of the classes to show the shape of the data.
- Data Analysis – Data analysis means turning raw data into answers. It follows a cycle: ask a question, collect data, clean it (remove errors, repeats and blanks), organise and transform it, analyse it with summaries such as mean, median, range and patterns, show it with a good chart, and draw a careful conclusion. Watch for outliers, small samples and bias, and remember that a correlation between two things does not prove that one causes the other. Data must also be stored safely and used with permission.
2. Geology
Rocks and minerals · Rock classification and rock cycle · Identifying local rocks and minerals · Uses of rocks and minerals · Basic structure of the geosphere
- Rocks and Minerals – A mineral is a natural, non-living solid with a fixed chemical make-up and a regular crystal shape, like quartz or halite. A rock is a mixture of one or more minerals. Rocks are of three types: igneous (from cooled magma or lava), sedimentary (from layers of pressed bits) and metamorphic (changed by heat and pressure). The rock cycle slowly turns each type into the others over millions of years.
- Resources and Development – A resource is anything in nature that people can use with the help of technology. Resources can be grouped by origin, by how long they last, by who owns them and by how much we have developed them. India must plan how it uses resources, look after its land, and protect its soils from erosion.
- Interior of the Earth: Earthquake Waves, Layers and Volcanoes – Nobody can dig to the centre of the Earth, so we learn about the inside from direct sources (mine rocks, deep drilling, lava) and indirect sources (heat and pressure with depth, meteors, gravity, magnetism and, above all, earthquake waves). P-waves travel through solids and liquids; S-waves only through solids. Where the waves do not arrive, we get shadow zones, which prove the outer core is liquid. Earthquakes are measured by magnitude (Richter) and intensity (Mercalli). The Earth has a thin crust, a thick mantle with a soft asthenosphere, a liquid outer core and a solid inner core. Magma that reaches the surface builds volcanoes; magma that cools inside forms intrusive landforms like batholiths, sills and dykes.
3. The cell
Cell as unit of life · Prokaryotic and eukaryotic cells · Observing cells under microscope
- The Cell: Basic Unit of Life – Every living thing is made of cells. Robert Hooke first saw cells in cork in 1665. Cells are prokaryotic (no true nucleus, like bacteria) or eukaryotic (true nucleus). Plant cells have a cell wall, chloroplasts and a big vacuole; animal cells do not. Each organelle has a job. Water enters and leaves cells by osmosis. Cells make new cells by mitosis (growth) and meiosis (sex cells).
4. Living things
Classifying living things into kingdoms · Main taxonomic groups · Identifying local species · Animals as sentient beings
- Diversity and Classification of Living Organisms – Earth has millions of kinds of living things, and India is one of the richest places. To study them, we sort them into groups by asking simple questions about their bodies: Is there a nucleus? One cell or many? Can it make its own food? This gives five kingdoms: Monera, Protista, Fungi, Plantae and Animalia. Animals split into invertebrates and vertebrates. Every species gets a two-part scientific name. Viruses are not cells, so they fit in no kingdom.
- Animal Behaviour: Why Animals Do What They Do – Behaviour is everything an animal does in reply to a stimulus from outside (a predator, light, a sound) or inside (hunger, hormones). Some behaviour is innate (instinct, born with it); some is learned (habituation, conditioning, imprinting, insight). Behaviour has a function: it helps the animal survive and reproduce, often by living in groups. Many animals are sentient: they can feel pain, fear and pleasure.
5. Ecology and sustainability
Local ecosystems · Conserving ecosystems and biodiversity · Atmosphere and hydrosphere functions · Earth spheres and soil · Climate change causes and effects · Sustainable habits · One Health
- Ecosystem, Food Chains and Energy Flow – An ecosystem is all the living things in a place plus the non-living things around them, working together. Energy enters as sunlight, passes one way up a food chain, and only about 10% moves to each next level.
- Biodiversity and its Conservation – Biodiversity is the variety of life at three levels: genetic, species and ecological. It is highest near the equator and grows with area (log S = log C + Z log A). Every species matters, like rivets on a plane. We are losing species fast because of the 'evil quartet': habitat loss and fragmentation, over-exploitation, alien species invasions and co-extinction. The IUCN Red List (Red Data Book) ranks species from Least Concern to Extinct. We protect life in situ (hotspots, national parks, sanctuaries, biosphere reserves, sacred groves, Ramsar wetlands) and ex situ (zoos, botanical gardens, seed and gene banks).
- Earth as a System: Spheres and Energy – Earth is like one big machine with five parts: rock (geosphere), water (hydrosphere), ice (cryosphere), air (atmosphere) and life (biosphere). The Sun powers it. Sunlight comes as many kinds of rays (the electromagnetic spectrum). The Sun heats Earth unevenly, and that makes winds, breezes and ocean currents. Water, carbon, nitrogen and oxygen move round and round between the spheres in cycles. Humans now change these cycles, so we must use Earth carefully.
- Soil: How It Forms, Its Layers and How to Protect It – Soil is the thin, loose top layer of the land where plants grow. It is a mix of rock grains (about 45%), organic matter or humus (about 5%), water (about 25%) and air (about 25%). Soil forms very slowly when weathering breaks parent rock and living things add humus. Five factors control it: parent rock, climate, living things, relief (slope) and time. A cut through the ground shows layers called horizons: O (litter and humus), A (topsoil), B (subsoil, where washed-down minerals collect), C (broken rock) and R (bedrock). Soil texture depends on the share of sand, silt and clay. Soil feeds plants, stores and cleans water, stores carbon and is home to countless organisms, but erosion, salt and pollution can destroy it far faster than it forms.
- Climate Change and the Greenhouse Effect – Climate is the average weather of a place over about 30 years. Greenhouse gases like carbon dioxide and methane trap some of the heat the Earth gives off. Humans have added a lot more of these gases by burning fossil fuels and cutting forests, so the Earth is warming. This causes melting ice, rising seas and more extreme weather. We can cut emissions (mitigation) and prepare for changes (adaptation).
- Sustainability – Sustainability means meeting our needs today without taking away the ability of future people to meet theirs. It rests on three pillars — environment, society and economy. A resource is used sustainably when we use it no faster than it renews. Today humanity uses about 1.7 Earths' worth of resources a year, and this use is very unequal. Stewardship, careful planning and spatial tools like GIS help us move towards sustainability.
- Environmental Health – Environmental health is about how our surroundings — air, water, food, soil, chemicals, noise, heat and the buildings we live in — affect our health. Harm reaches the body by four roads: breathing, drinking, eating and touching. Risk depends on the dose and how long we are exposed. Some poisons build up along food chains. The One Health idea says human, animal and environmental health are linked, so we protect all three together.
6. Human body
Nutrition function · Main human organ systems · Interaction function overview · Linking body systems
- Human Body Systems – Your body is organised in levels: cells make tissues, tissues make organs, organs make organ systems, and all systems together make you, the organism. Each system has a main job: skeletal (frame), muscular (movement), circulatory (transport), respiratory (gas exchange), digestive (food), excretory (waste), nervous and endocrine (control), immune (defence), integumentary (skin, hair, nails) and reproductive. No system works alone: during exercise the muscles, heart, lungs and nerves all change together to keep the inside of the body steady (homeostasis).
- Neural Control and Coordination – Coordination means organs working together. The nervous system does this fast, using neurons. A neuron has a cell body, dendrites and an axon; many axons have a myelin sheath with nodes of Ranvier. The central nervous system (brain and spinal cord) processes information; the peripheral nervous system (nerves) carries it. The PNS has a somatic part (skeletal muscles) and an autonomic part (sympathetic and parasympathetic) for internal organs, the visceral system. At rest the axon is polarised: inside −, outside +, about −70 mV. A stimulus lets Na+ rush in, creating an action potential that travels along the axon. At a synapse, neurotransmitters carry the signal to the next neuron.
7. Healthy habits
Healthy diet · Sex, sexuality and respect · Relationships and sexual health education · Legal and illegal drugs · Healthy lifestyle habits
- Nutrition – Nutrition is how we get and use the substances in food. The body needs six groups of nutrients: carbohydrates and fats (mainly energy), proteins (growth and repair), vitamins and minerals (small amounts to keep the body working), and water, plus fibre for healthy digestion. Carbohydrate and protein give about 17 kJ per gram, fat about 37 kJ per gram. A balanced diet gives all nutrients in the right amounts, and energy in should roughly equal energy out.
- Reproduction in Human Beings and Reproductive Health – At puberty, hormones from the brain make the testes and ovaries start working. The male system makes and carries sperm; the female system makes eggs and provides a place (uterus) where a baby develops. Fertilisation happens in the oviduct, and the embryo is fed through the placenta. Reproductive health includes safe choices, contraception, avoiding female foeticide, and preventing sexually transmitted diseases such as HIV/AIDS.
- Reproductive Health – Reproductive health means being well in body, mind, behaviour and social life in all matters of reproduction. It needs correct information, safe and hygienic habits, prevention of sexually transmitted infections (STIs), and access to safe birth control, legal abortion (MTP) and care for infertility. Birth-control methods act at different points: natural methods avoid fertile days, barriers block sperm, IUDs stop sperm and implantation, pills stop ovulation and surgery cuts the tubes. Assisted reproductive technologies such as IVF-ET, ZIFT, IUT, GIFT, ICSI and IUI help couples who cannot conceive.
- Addiction: How It Starts and How to Stay Free – Addiction is losing control over a substance or a behaviour, even when it causes harm. It can be to substances (tobacco, alcohol, drugs, misused medicines) or to behaviours (gaming, gambling, social media). Each use gives the brain a burst of dopamine, which teaches it to repeat the action; with time tolerance grows and you need more. Warning signs are craving, loss of control, compulsion and carrying on despite harm. Protection comes from refusal skills, healthy rewards, sleep and routine, and asking for help early. Addiction is treatable.
- Healthy Lifestyle: Daily Habits That Keep You Well – A healthy lifestyle is a set of daily habits: a balanced diet from five food groups, enough water, 9–11 hours of sleep for school-age children and about 8–10 for teenagers, at least 60 minutes of activity a day, good posture, safe food handling and avoiding tobacco, alcohol and drugs. These habits lower the risk of lifestyle (non-communicable) diseases such as type 2 diabetes, heart disease and some cancers.
8. Health and disease
Infectious and non-infectious diseases · Preventing and treating infections · Body barriers against pathogens · Body defence mechanisms · Importance of vaccination · Transplants and organ donation
- Infectious Diseases: How Germs Spread and How We Stop Them – An infectious (communicable) disease is caused by a tiny living thing called a pathogen: a bacterium, virus, fungus or protist. It passes from one person to another through air, water and food, touch, or a vector such as a mosquito. The body fights back with skin, mucus, stomach acid and white blood cells. Vaccines train the immune system in advance. Hand washing, clean water, cooking food well, mosquito nets and staying home when sick all cut the spread.
- The Immune System: How Your Body Fights Germs – Germs (pathogens) cause infectious disease. The body has three lines of defence: barriers (skin, mucus, acid), a fast general (innate) response (inflammation, fever, phagocytes) and a slow, specific (adaptive) response (B cells make antibodies, T cells kill infected cells). Memory cells make the second attack fast. Vaccines create memory safely. Immunity can go wrong: allergy, autoimmune disease, immunodeficiency (e.g. HIV).
- Human Health and Disease – Health means the body, mind and social life all work well. Diseases can be caused by germs (pathogens) like bacteria, viruses, protozoa, worms and fungi. Our body fights them with two kinds of immunity: innate (we are born with it) and acquired (it learns and remembers). Vaccines use this memory. HIV destroys helper T cells and causes AIDS. Cancer is cells dividing without control. Drugs and alcohol harm the body and mind, especially in teenagers.