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Understanding Characteristics of Living Things

ο»ΏπŸ“˜ Characteristics of Living Things All living organisms share several key characteristics that define life. Understanding these traits is fundamental in biology. 1. Made of Cells * Definition: All living organisms are composed of one or more cells, which are considered the basic units of life. * Types: * Unicellular: Organisms consisting of a single cell (e.g., Amoeba, Paramecium). * Multicellular: Organisms composed of multiple cells (e.g., humans, plants). 2. Use Energy (Metabolism) * Definition: Living organisms require energy to perform various functions such as growth, repair, and maintenance. * Processes: * Photosynthesis: Used by plants to convert sunlight into chemical energy. * Cellular Respiration: Used by animals and plants to convert glucose into usable energy (ATP). 3. Respond to Stimuli * Definition: The ability to detect and respond to environmental changes. * Examples: * Blinking when something comes close to your eye β€” Your eyes close quickly to protect themselves. * Pulling your hand away from a hot surface β€” You quickly move your hand away to avoid getting burned. * Coughing when something irritates your throat β€” Your body tries to clear the throat to protect your airway. 4. Maintain Homeostasis * Definition: The regulation of internal conditions to maintain a stable internal environment. * Simple Definition: The body's ability to maintain a stable internal environment. * Examples: * Sweating to cool down β€” When your body gets too hot, you sweat, and the evaporation of sweat helps lower your body temperature. * Shivering to warm up β€” When you feel cold, your muscles shake (shiver) to generate heat and raise your body temperature. * Regulating blood sugar β€” After eating, your body releases insulin to lower high blood sugar levels, keeping it balanced. 5. Grow and Develop * Definition: Growth refers to an increase in size and mass, while development involves progression through life stages. * Examples: * A caterpillar developing into a butterfly. * Humans’ hair and nails are getting longer. * A seed growing into a plant 6. Reproduce * Definition: The biological process by which new individual organisms are produced. * Types: * Asexual Reproduction: Involves a single parent; offspring are genetically identical. Methods include: * Budding: e.g., Hydra. * Fragmentation: e.g., Planaria. * Binary Fission: e.g., Bacteria. * Spore Formation: e.g., Fungi. * Binary Fission: The most common method where a single cell divides into two identical daughter cells. The genetic material is duplicated, and the cell splits. * Budding: A new organism grows as an outgrowth or bud from the parent. This bud eventually detaches and becomes a new individual. * Fragmentation: The organism breaks into fragments, and each fragment develops into a new individual. * Spore Formation: Some bacteria form spores that can develop into new individuals under favorable conditions. * Sexual Reproduction: Involves two parents; offspring have genetic variation.BYJU'SBYJU'S+1BYJU'S+1 πŸ“– Parts of a Flower Involved 1. Stamen – The male part of the flower. * Anther: Produces pollen grains (which contain the male gametes). * Filament: Supports the anther. 2. Carpel (Pistil) – The female part of the flower. * Stigma: Sticky tip that catches pollen. * Style: Tube that connects stigma to ovary. * Ovary: Contains ovules (which have female gametes). ________________ πŸ”„ Steps in Sexual Reproduction 1. Pollination Pollen is transferred from the anther to the stigma. This can happen by: * Wind * Insects * Water * Animals 2. Fertilization * A pollen grain grows a pollen tube down the style to the ovary. * The male gamete travels through the tube and fuses with the female gamete in the ovule. * This forms a zygote. 3. Seed and Fruit Formation * The zygote becomes an embryo inside a seed. * The ovule becomes the seed, and the ovary becomes the fruit. Aspect Asexual Reproduction Sexual Reproduction Number of Parents Only one parent Two parents Genetic Variation Offspring are genetically identical (clones) Offspring have genetic variation (mix of parents' genes) Process Involves processes like budding, binary fission, fragmentation, spores Involves the fusion of male and female gametes (sperm and egg) Speed Usually faster since no mating is required Generally slower due to mating and fertilization process Examples Bacteria (binary fission), Hydra (budding), fungi (spores), starfish (fragmentation) Most animals and plants, including humans, birds, flowering plants Advantages - Quick reproduction - No need to find a mate - Useful in stable environments - Creates genetic diversity - Helps populations adapt to changing environments Disadvantages - No genetic diversity - Less adaptable to environmental changes - Requires finding a mate - Slower reproduction rate 7. Contain Genetic Material * Definition: All living organisms possess DNA (or RNA in some viruses) that carries genetic information necessary for growth, development, and reproduction. 8. Adaptation in Animals Definition: The ability of living things to adjust to changes in their environment to survive, without changes to their DNA or species over generations. These adaptations are behavioral, physiological, or structural. Examples: * Behavioral: Bears hibernate during winter to conserve energy when food is hard to find. * Structural: Rabbits have big ears to help them hear predators. * Physiological: A snake's ability to produce venom 9. Adaptation in Plants: Plant Adaptations in Different Habitats * Deserts: Plants like cactus have small leaves or spines to save water. They also have roots close to the surface to grab water quickly. Examples: Cactus and Joshua Tree. * Tropical Rainforests: Plants have drip tips and waxy leaves to get rid of extra water. Some plants grow on others to reach sunlight. Examples: Bromeliads and Lianas. * Temperate Forests: Trees have thick bark to protect them from the cold. Some trees drop their leaves in the fall to save water. Examples: Wildflowers, Oak, Ash, Maple, etc. * Water: Water plants have special leaves that are green on top and red underneath. They don't need strong stems because they don't need to absorb water. Examples: Water lily and Lotus. Important Points * Moving plants to a new place can be hard for them because they are used to their home. * Adaptation is a slow process. * Changes in a plant's adaptations can be either helpful or harmful. 🧬 Cell Structure and Function Understanding the structure and function of cells is crucial, as they are the building blocks of life. πŸ”Ή Plant Cell Diagram and Organelles Oak National Academy+10BYJU'S+10Storyboard That+10 * Cell Wall: Provides structural support and protection; composed of cellulose. * Cell Membrane: Regulates the movement of substances in and out of the cell. * Nucleus: Contains genetic material (DNA) and controls cellular activities. * Chloroplasts: Site of photosynthesis; contains chlorophyll. * Vacuole: Stores nutrients and waste products; maintains turgor pressure. * Mitochondria: Powerhouse of the cell; site of cellular respiration. * Endoplasmic Reticulum (Rough and Smooth): Synthesizes proteins (rough ER) and lipids (smooth ER). * Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for storage or transport.BYJU'S πŸ”Ή Animal Cell Diagram and Organelles BYJU'S+21GeeksforGeeks+21Oak National Academy+21 * Cell Membrane: Same function as in plant cells. * Nucleus: Same function as in plant cells. * Mitochondria: Same function as in plant cells. * Endoplasmic Reticulum (Rough and Smooth): Same function as in plant cells. * Golgi Apparatus: Same function as in plant cells. * Lysosomes: Contain digestive enzymes to break down waste. * Centrioles: Involved in cell division. ________________ 🌍 Necessities of Life in Different Organisms Different organisms have varying requirements for survival. * Air/Gases: * Oxygen: Required by most animals for cellular respiration. * Carbon Dioxide: Utilized by plants during photosynthesis.BYJU'S * Source of Energy: * Autotrophs: Produce their own food (e.g., plants via photosynthesis). * Heterotrophs: Consume other organisms for energy (e.g., animals). * Space: * Necessary for growth, reproduction, and access to resources. ________________ 🧠 Specialized Cells and Adaptations Specialized cells have unique structures that enable them to perform specific functions. πŸ”Ή Examples in Animals: * Red Blood Cells: Biconcave shape increases surface area for oxygen transport. * Nerve Cells (Neurons): Long extensions (axons) transmit electrical signals. * Muscle Cells: Contain fibers that contract for movement. πŸ”Ή Examples in Plants: * Root Hair Cells: Extended surface area for water and nutrient absorption. * Guard Cells: Regulate gas exchange by opening and closing stomata. * Xylem Cells: Transport water from roots to leaves. ________________ πŸ—οΈ Key Terms * Unicellular: Organisms consisting of a single cell. * Multicellular: Organisms composed of multiple cells. * Prokaryotic: Cells without a nucleus (e.g., bacteria). * Eukaryotic: Cells with a nucleus (e.g., plant and animal cells). * Homeostasis: Maintenance of a stable internal environment. * Reproduction: * Asexual: Single parent; offspring are clones. * Sexual: Two parents; offspring have genetic variation. * Stimuli: Environmental changes that elicit responses from organisms.BYJU'S+9BYJU'S+9BYJU'S+9 ________________ πŸ“š Additional Resources For further reading and visual aids, consider exploring the following resources: * Characteristics of Living Things: Biology LibreTexts * Sexual and Asexual Reproduction: BYJU'S * Plant and Animal Cell Differences: BYJU'S * Specialized Cells and Adaptations: 🧬 CHARACTERISTICS OF LIVING THINGS All living things share specific characteristics: Characteristic Explanation Example Made of cells All organisms are made of one (unicellular) or many cells (multicellular). Amoeba (unicellular), Humans (multicellular) Use energy Living things need energy to perform life processes. Plants use sunlight (photosynthesis), animals eat food Respond to stimuli Organisms respond to changes in their environment (stimuli). A plant bending toward sunlight Homeostasis Maintaining a stable internal environment. Sweating to cool down body temperature Grow and develop Organisms grow by increasing cell number or size and undergo changes. Baby growing into an adult Reproduce Ability to create offspring. Can be asexual or sexual. Bacteria split (asexual), Humans (sexual) Genetic material All living things have DNA or RNA. DNA in the nucleus Adaptation Traits that help organisms survive and reproduce. Thick fur in arctic animals ________________ πŸ“— VOCABULARY (KNOW + UNDERSTAND) Word Meaning Unicellular Made of one cell Multicellular Made of many cells Prokaryotic Simple cells with no nucleus (e.g., bacteria) Eukaryotic Complex cells with a nucleus (e.g., plant and animal cells) Homeostasis The process of maintaining internal balance Reproduction Making new organisms Asexual reproduction One parent β†’ identical offspring (e.g., budding, fragmentation) Sexual reproduction Two parents β†’ genetically different offspring Stimuli (plural of stimulus) Things that cause a response in living things (e.g., heat, light) ________________ 🧫 CELL STRUCTURE: PLANT VS ANIMAL Both plant and animal cells are eukaryotic and share many organelles but also have key differences. ________________ 🌿 PLANT CELL DIAGRAM (From your image) Organelle Function Cell Wall Supports and protects the plant cell Cell Membrane Controls what enters/leaves the cell Vacuole Stores water and nutrients; large in plant cells Nucleus Controls the cell; holds genetic material (DNA) Nucleolus Makes ribosomes Nuclear Membrane Protects the nucleus Chloroplast Site of photosynthesis (uses sunlight for food) Mitochondrion Powerhouse of the cell (releases energy) Cytoplasm Jelly-like fluid where organelles float, and it holds the internal components of cells in place and protects them from damage. Amyloplast Stores starch Golgi Body Packages and transports materials Smooth ER Makes lipids, detoxifies Rough ER Has ribosomes; helps make proteins Ribosomes Make proteins Centrosome Helps in cell division ________________ 🐾 ANIMAL CELL DIAGRAM Organelle Function Cell Membrane Outer layer; controls movement in/out of cell Cytoplasm Fluid where cell parts are suspended Nucleus Controls cell’s functions; holds DNA Nucleolus Makes ribosomes inside the nucleus Nuclear Membrane Protects and separates nucleus from cytoplasm Mitochondria Produces energy (cell respiration) Ribosomes Protein synthesis Golgi Body Modifies and sends out proteins Rough ER Transports proteins made by ribosomes Smooth ER Makes lipids Centrioles Help during cell division (not in plants) Lysosomes Breaks down waste and old cell parts (mainly in animals) ________________ πŸ§ͺ NECESSITIES OF LIFE All organisms need these to survive: Need Why it's important Water Needed for chemical reactions Energy source To do work (sunlight for plants, food for animals) Gases (Oxygen/Carbon Dioxide) Used in respiration (O2 for animals) and photosynthesis (CO2 for plants) Space To grow and reproduce Stable environment To maintain homeostasis ________________ 🧠 SPECIALIZED CELLS & ADAPTATIONS Some cells have special shapes or parts to help them do their job well. Cell Function Adaptation Red blood cell Carry oxygen No nucleus, large surface area Nerve cell Send messages Long body to carry signals quickly Muscle cell Help movement Can contract and relax Root hair cell (plant) Absorb water Long extension for more surface area Palisade cell (plant) Photosynthesis Packed with chloroplasts ________________ πŸ“˜ HOW TO SURVIVE BOOKLET SUMMARY This booklet explained how different organisms show the 8 characteristics of life in different ways. For example: * Bacteria: Unicellular, asexual, prokaryotic * Plants: Multicellular, use sunlight, reproduce sexually/asexually * Humans: Complex systems (digestive, respiratory) to survive * Cactus: Thick stem stores water (adaptation) * Fish: Gills for gas exchange ________________ πŸ“š RESOURCES USED All information above was supported by: * LibreTexts: Characteristics of Living Things * Sexual & Asexual Reproduction * Homeostasis Video * Animal & Plant Cell Video * Plant vs Animal Cell Article * Adaptation in Animals * Adaptation in Plants ________________ πŸ“ PRACTICE QUESTIONS (with answers) Q1. List all characteristics of living things and give one example for each. A: * Made of cells β†’ Human * Use energy β†’ Tiger hunting * Respond to stimuli β†’ Leaves closing at night * Homeostasis β†’ Human body temperature stays 37Β°C * Grow and develop β†’ Tadpole β†’ Frog * Reproduce β†’ Plants via seeds * Genetic material β†’ DNA in nucleus * Adaptation β†’ Giraffe’s long neck ________________ Q2. Compare plant and animal cells. Give 3 similarities and 3 differences. Similarities Differences Both have nucleus Only plants have chloroplasts Both have mitochondria Only plant cells have a cell wall Both have cytoplasm Animal cells have centrioles, plants do not ________________ Q3. What is the function of the mitochondria and why is it important? A: It releases energy from food during cellular respiration, which is used for all life processes.