Biology Notes PDF

· Classification: why do we classify living things? · 8 characteristics of living things and their descriptions · 7 Levels of Classification · Photosynthesis (what is it, why is it important?) · 6 kingdoms (what types of living things fit in each, how is each group special?) · The m...

· Classification: why do we classify living things? · 8 characteristics of living things and their descriptions · 7 Levels of Classification · Photosynthesis (what is it, why is it important?) · 6 kingdoms (what types of living things fit in each, how is each group special?) · The microscope parts · Protists · Bacteria – beneficial functions of bacteria · Fungi · Features of the main animal Phylum & Classes · Plants · Dichotomous keys: how to classify things 1. Classification of Living Things ​ Why do we classify living things? ○​ Organization: It helps us organize the vast diversity of life on Earth into manageable groups. ○​ Understanding Relationships: Classification reveals evolutionary relationships between different organisms. ○​ Communication: It provides a standardized system for scientists to communicate about organisms worldwide. ○​ Identification: It helps us identify and name organisms accurately. 2. 8 Characteristics of Living Things 1.​ Organization: All living things are composed of cells, the basic units of life. 2.​ Growth and Development: Living things increase in size (growth) and undergo changes throughout their lifespan (development). 3.​ Reproduction: Living things produce offspring, ensuring the continuation of their species. 4.​ Response to Stimuli: Living things react to changes in their environment, such as light, temperature, or touch.  5.​ Homeostasis: Living things maintain a stable internal environment despite external changes. 6.​ Energy Use: Living things obtain and use energy to carry out life processes. 7.​ Adaptation: Living things have traits that help them survive and reproduce in their specific environments. 8.​ Evolution: Living things change over time through the process of evolution. 3. 7 Levels of Classification 1.​ Kingdom: The broadest category, grouping organisms based on fundamental characteristics. 2.​ Phylum: A more specific grouping within a kingdom. 3.​ Class: A further subdivision within a phylum. 4.​ Order: A more specific grouping within a class. 5.​ Family: A more specific grouping within an order. 6.​ Genus: A group of closely related species. 7.​ Species: The most specific level, representing a group of organisms that can interbreed and produce fertile offspring. 4. Photosynthesis ​ What is it? Photosynthesis is the process by which green plants and some other organisms convert light energy into chemical energy. ​ Why 1 is it important? ○​ Primary Energy Source: It's the foundation of most food webs, providing energy for almost all life on Earth. ○​ Oxygen Production: Photosynthesis releases oxygen as a byproduct, essential for the survival of many organisms. ○​ Carbon Dioxide Removal: It helps regulate the Earth's atmosphere by removing carbon dioxide, a greenhouse gas. ​ ​ 1. www.answeree.com ​ www.answeree.com ​ 5. 6 Kingdoms 1.​ Animalia: ○​ Characteristics: Multicellular, eukaryotic (cells with a nucleus), heterotrophic (obtain food by consuming other organisms), capable of movement. ○​ Examples: Mammals, birds, reptiles, amphibians, fish, insects. 2.​ Plantae: ○​ Characteristics: Multicellular, eukaryotic, autotrophic (produce their own food through photosynthesis), mostly immobile. ○​ Examples: Trees, flowers, grasses, ferns, mosses.  3.​ Fungi: ○​ Characteristics: Eukaryotic, heterotrophic (obtain food by absorbing nutrients from their surroundings), have cell walls made of chitin. ○​ Examples: Mushrooms, yeasts, molds. 4.​ Protista: ○​ Characteristics: A diverse group, mostly unicellular, eukaryotic, can be autotrophic or heterotrophic. ○​ Examples: Amoeba, paramecium, algae. 5.​ Archaea: ○​ Characteristics: Unicellular, prokaryotic (lack a true nucleus), often live in extreme environments. ○​ Examples: Methanogens, halophiles, thermophiles. 6.​ Bacteria: ○​ Characteristics: Unicellular, prokaryotic, diverse in structure and metabolism. ○​ Examples: E. coli, Streptococcus, Lactobacillus. 6. Microscope Parts ​ Eyepiece: The lens you look through to view the specimen. ​ Objective Lenses: Multiple lenses with different magnifications. ​ Stage: The platform where the slide with the specimen is placed. ​ Light Source: Provides illumination for viewing the specimen. ​ Diaphragm: Controls the amount of light reaching the specimen. ​ Coarse Focus Knob: Used for initial focusing. ​ Fine Focus Knob: Used for precise focusing. ​ Base: The bottom of the microscope, providing support. ​ Arm: Connects the base to the body tube, used for carrying the microscope. 7. Protists Protists are a diverse group of eukaryotic organisms. They can be unicellular or multicellular, and they exhibit a wide range of characteristics. Some protists are autotrophic (like algae), while others are heterotrophic (like amoeba). 8. Bacteria ​ Beneficial Functions: ○​ Food Production: Used in the production of yogurt, cheese, and other fermented foods. ○​ Environmental Cleanup: Decompose organic matter, helping to recycle nutrients in the environment. ○​ Medicine: Used to produce antibiotics and other medications. ○​ Biotechnology: Used in genetic engineering and other biotechnological applications. 9. Fungi Fungi are eukaryotic organisms that obtain nutrients by absorbing them from their surroundings. They play crucial roles in decomposition and nutrient cycling. Some fungi, like mushrooms, are edible, while others can cause diseases in plants and animals. 10. Features of the Main Animal Phylum & Classes ​ Phylum Chordata:​ ○​ Characteristics: Presence of a notochord (a flexible rod-like structure) at some point in their development, dorsal hollow nerve cord, pharyngeal slits, post-anal tail. ○​ Classes: ​ Mammalia: Warm-blooded, have hair or fur, mammary glands for producing milk. ​ Aves: Birds, warm-blooded, have feathers, lay eggs. ​ Reptilia: Cold-blooded, scaly skin, lay eggs. ​ Amphibia: Cold-blooded, smooth, moist skin, undergo metamorphosis. ​ Chondrichthyes: Cartilaginous fishes, skeletons made of cartilage (e.g., sharks, rays). ​ Osteichthyes: Bony fishes, skeletons made of bone. ​ Phylum Arthropoda:​ ○​ Characteristics: Exoskeleton made of chitin, jointed appendages, segmented bodies. ○​ Classes: ​ Insecta: Six legs, three body segments (head, thorax, abdomen). ​ Arachnida: Eight legs, two body segments (cephalothorax, abdomen) (e.g., spiders, scorpions). ​ Crustacea: Hard exoskeleton, multiple pairs of legs (e.g., crabs, lobsters). ​ Phylum Mollusca:​ ○​ Characteristics: Soft-bodied animals, often with a shell. ○​ Classes: ​ Gastropoda: Snails, slugs. ​ Bivalvia: Clams, oysters. ​ Cephalopoda: Octopuses, squids. ​ Phylum Annelida:​ ○​ Characteristics: Segmented worms, have bristles on their bodies. ○​ Examples: Earthworms, leeches. ​ Phylum Nematoda:​  ○​ Characteristics: Roundworms, unsegmented, lack a circulatory system. ​ Phylum Platyhelminthes:​ ○​ Characteristics: Flatworms, bilaterally symmetrical, lack a body cavity. ​ Phylum Porifera:​ ○​ Characteristics: Sponges, simplest animals, lack true tissues and organs. ​ Phylum Cnidaria:​ ○​ Characteristics: Jellyfish, corals, anemones, have stinging cells called cnidocytes. 11. Plants Plants are multicellular, eukaryotic organisms that are primarily autotrophic. They play a vital role in the ecosystem by producing oxygen and providing food for other organisms. Plants are classified into various groups based on their characteristics, such as the presence or absence of vascular tissues, seeds, and flowers. 12. Dichotomous Keys ​ How to Classify Things: ○​ A dichotomous key is a tool used to identify organisms based on a series of paired statements. ○​ Each pair of statements presents two contrasting characteristics. ○​ By choosing the statement that best describes the organism, you are directed to the next pair of statements. ○​ This process continues until you reach the final identification of the organism.