Romania Clasa a VIII-a Biology
Chapters: 3
1. Heredity and variation in humans
Genetic material · Passing on genetic material
- Heredity and Mendel's Laws – Heredity is the passing of traits from parents to children through genes. Each parent gives one copy of every gene. A dominant copy hides a recessive one, which is why Mendel saw 3:1 in a monohybrid cross and 9:3:3:1 in a dihybrid cross. Genes are pieces of DNA that make proteins, and proteins build the trait.
2. Evolution
Origin and evolution of life · Evidence of evolution · Factors of evolution · Human evolution
- Evolution: How New Kinds of Living Things Arise – Variations arise during reproduction. Nature selects those that help survival, so over many generations populations change: this is evolution. Only inherited (DNA) changes pass on; acquired changes do not. Separated populations can become new species. Homologous organs, analogous organs and fossils help us trace who is related to whom, and complex organs evolved step by step.
- Evolution: Origin of Life, Mechanisms and Human Evolution – Life began on the early Earth from simple chemicals: Oparin and Haldane proposed it and Miller made amino acids in a flask. Evidence of evolution comes from fossils, homologous and analogous organs, embryos, molecules and changes we can watch (industrial melanism, drug resistance). Darwin explained it by natural selection acting on variation in populations; the modern synthetic theory adds genes: mutation, recombination, gene flow, genetic drift and natural selection change allele frequencies. If none of these act, frequencies stay constant: Hardy–Weinberg, p² + 2pq + q² = 1. Selection can be stabilising, directional or disruptive. One ancestor spreading into many habitats gives adaptive radiation (Darwin’s finches, Australian marsupials). Humans evolved from Dryopithecus-like apes through Australopithecus, Homo habilis, Homo erectus and Neanderthals to Homo sapiens.
3. Human and environmental health
Quality of the environment · Environment- and lifestyle-related diseases · People and technology · Energy resources, biodiversity, sustainability
- Pollution: Air, Water, Land and Noise – Pollution is the release of harmful substances or energy into air, water or land faster than nature can remove them. Main air pollutants are particulates, carbon monoxide, sulfur dioxide, nitrogen oxides and ozone; they cause acid rain and smog. Water pollution by nutrients, sewage and toxins causes eutrophication and biomagnification. We reduce pollution by cutting emissions at the source, cleaning waste before release, and the 3Rs.
- Science, Technology and Society: How Discoveries Change Our Lives – Science finds out how nature works; technology uses that knowledge to make tools and solve problems. Society shapes science too, by asking questions, paying for research and making rules. Big changes such as the printing press, the steam engine, electricity, vaccines and the internet changed how people work, live and think. Every technology has benefits and risks. To decide wisely we look at evidence, weigh benefits against risks, ask who gains and who loses, think about ethics and the future, and use safety rules.