Russia 7 класс Biology (basic)

Chapters: 5

1. Systematic groups of plants

Plant classification · Algae · Mosses · Clubmosses, horsetails, ferns · Gymnosperms · Flowering plants · Families of flowering plants

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.
Algae – Algae are simple living things that live mostly in water and make food from sunlight. They have no true roots, stems or leaves. They can be one cell or very long. Green, brown and red algae have different pigments. They make oxygen and feed water animals.
Flowering Plants (Angiosperms) – Angiosperms are plants that make flowers, and their seeds grow inside fruits. They are split into two groups. Dicots have 2 seed leaves, taproot, net-veined leaves and flowers in 4s or 5s. Monocots have 1 seed leaf, fibrous roots, parallel veins and flowers in 3s.

Evolution of plants

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.

Plants and environment · Plant communities

Coming soon

Cultivated plants

Agriculture Basics: How Farming Began, Changed and Feeds the World – Agriculture is growing crops and raising animals on purpose. It began about 10,000–12,000 years ago in several separate hearths, where people domesticated wild plants and animals; it then spread by diffusion. The Second Agricultural Revolution (about 1700–1900) brought better tools, crop rotation and machines, so fewer farmers fed more people. The Green Revolution (from the 1960s) used high-yield seeds, irrigation and fertiliser. Farming can be subsistence or commercial, intensive or extensive. The von Thünen model explains why land use forms rings around a market. Today agriculture is a global system facing challenges of sustainability, climate, land use, food security and fair roles for women.

Fungi · Lichens · Bacteria

Fungi: Mushrooms, Moulds, Yeast and Lichens – Fungi are living things with cells that have a nucleus and a cell wall made of chitin. They have no chlorophyll, so they cannot make food. Most are made of thin threads called hyphae; a net of hyphae is a mycelium. Fungi pour digestive juices onto food and absorb what dissolves. They spread by tiny spores. Mushrooms, moulds and yeast are fungi. A lichen is a fungus living together with an alga.
Bacteria: Tiny Cells That Run the Planet – Bacteria are single-celled prokaryotes: they have no nucleus and no membrane-bound organelles. Their DNA is one circular loop (the nucleoid), often with small extra rings called plasmids. They have 70S ribosomes, a cell membrane, a cell wall of peptidoglycan, and may have a capsule, pili and flagella. Shapes: coccus, bacillus, spirillum, vibrio. They reproduce by binary fission and can swap genes sideways by conjugation, transformation and transduction. They feed by photosynthesis, chemosynthesis, decomposition, symbiosis or parasitism, and drive the carbon and nitrogen cycles. Archaea look similar but differ in wall and membrane chemistry and often live in extreme places.