Biology Class

Health benefits of Taraxicum officinale. A dendelion plant.
“Dandelion isn’t just a w**d 🌼 It’s a medicinal powerhouse! ”

5 April 2026 “Dandelion isn’t just a w**d 🌼 It’s a medicinal powerhouse! ”

Level of Biological Organisation 📙

The cell was first discovered by English scientist Robert Hooke in 1665, who observed dead cork cells using a primitive microscope and named the compartments "cells" after monastery rooms, publishing his findings in Micrographia. Soon after, Antonie van Leeuwenhoek (1674) was the first to see living cells, including bacteria, in pond water with his improved microscope. Later, Robert Brown (1831) identified the nucleus, and Schleiden & Schwann (1838-39) developed the fundamental Cell Theory, stating all living things are made of cells.
Key Discoverers & Milestones:
Robert Hooke (1665): Observed dead plant cells in cork, named them "cells," and published in Micrographia.
Antonie van Leeuwenhoek (1674): First to see living cells (bacteria, protozoa) in pond water and plaque, calling them "animalcules".
Robert Brown (1831): Discovered the nucleus within plant cells.
Matthias Schleiden (1838) & Theodor Schwann (1839): Proposed the Cell Theory, stating plants and animals are made of cells.
Rudolf Virchow (1855): Added that all cells arise from pre-existing cells (omnis cellula e cellula).
Impact:
This series of discoveries revealed cells as the basic building blocks of life, revolutionizing biology, medicine, and our understanding of health and disease, leading to modern fields like genetics and personalized medicine.

A trophic level is an organism's position in a food chain, indicating how it gets its energy. The levels are: 1. Producers (plants, algae), 2. Primary Consumers (herbivores), 3. Secondary Consumers (carnivores/omnivores that eat primary consumers), 4. Tertiary Consumers (carnivores that eat secondary consumers), and so on. Understanding these levels is crucial for studying the flow of energy through an ecosystem.
The different trophic levels
First Trophic Level (Producers): These organisms produce their own food, usually through photosynthesis, forming the base of the food chain.
Examples: Plants, algae, and some bacteria.
Second Trophic Level (Primary Consumers): These are herbivores that eat producers.
Examples: Deer, rabbits, grasshoppers, and insects.
Third Trophic Level (Secondary Consumers): These are carnivores or omnivores that feed on primary consumers.
Examples: Frogs, foxes, and small birds.
Fourth Trophic Level (Tertiary Consumers): These are carnivores or omnivores that prey on secondary consumers.
Examples: Snakes, hawks, and large fish.
Higher Trophic Levels: These levels continue with quaternary consumers and apex predators at the top of the food chain.
Decomposers: Organisms like worms and fungi that break down dead organic matter and waste from all trophic levels.
Key concepts
Energy Transfer: Energy is transferred from one trophic level to the next as organisms are consumed. However, this transfer is very inefficient, with a significant amount of energy being lost at each step.
Biomass: The total mass of organisms at a given trophic level is called its biomass. Biomass generally decreases at higher trophic levels because of the energy loss during transfer.
Food Chain vs. Food Web: A food chain shows a single path of energy flow, while a food web is a more realistic representation of an ecosystem, showing interconnected food chains.

Food Chain 🏓

food chain

Fig

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