Earth and Life Science Scope PDF

**Lesson 1: Origins of Life** **1. Creationism** - Traditionally associated with various religious beliefs; theologians, and religious philosophers. - The belief that life on Earth was created by a divine being or supernatural entity. This view is rooted in religious and spiritual...

**Lesson 1: Origins of Life** **1. Creationism** - Traditionally associated with various religious beliefs; theologians, and religious philosophers. - The belief that life on Earth was created by a divine being or supernatural entity. This view is rooted in religious and spiritual traditions that describe life as a purposeful creation rather than a product of natural processes. - **Examples**: Biblical Creationism (e.g., the Book of Genesis in Christianity), Islamic Creation narratives, and other creation myths around the world. **2. Panspermia** - Suggested by scientists like Svante Arrhenius and Fred Hoyle. - The hypothesis that life exists throughout the universe and was brought to Earth via meteoroids, comets, or cosmic dust. Panspermia suggests that microbial life could have originated in space and \"seeded\" Earth, rather than life originating here alone. - **Examples**: Microorganisms discovered in extreme environments on Earth, theories regarding the survival of bacteria in space, and studies of organic molecules in meteorites. **3. Physical and Chemical Theory** - J.B.S. Haldane, Alexander Oparin. - Proposes that life originated from simple chemical compounds through a series of complex chemical reactions powered by environmental factors like lightning and ultraviolet radiation. The theory involves the formation of complex organic molecules that eventually gave rise to living cells. - **Examples**: The Miller-Urey experiment, which simulated early Earth conditions and led to the formation of amino acids from inorganic precursors. **4. Abiogenesis** - Many modern scientists in the field of biochemistry and evolutionary biology. - The theory that life arose naturally from non-living matter through chemical processes on early Earth. Unlike creationism, it does not involve supernatural forces. Abiogenesis suggests that life started from self-replicating molecules, which eventually led to the diversity of life. - **Examples**: RNA world hypothesis, suggesting RNA was a precursor to life due to its ability to store genetic information and catalyze chemical reactions. **5. Biogenesis** - Louis Pasteur and Rudolf Virchow. - The principle that life arises only from pre-existing life, countering the concept of spontaneous generation. This theory suggests that all life forms originate from other living organisms, which has been foundational to the study of microbiology and modern biological sciences. - **Examples**: Pasteur\'s experiment disproving spontaneous generation by showing that sterilized broth remained free of life unless exposed to contamination from existing organisms. **Lesson II: Characteristics of Life and Unifying Themes in Life Science** Even though an amazing variety of living things exist on Earth, they are all alike in several ways. **Characteristics of Life** In study of life, there is an array of biological characteristics or properties and certain theme about how the living world works that are discussed. These properties are shared by all living things passed down over billions of years from the first organisms to have evolved on Earth. The Characteristics common to all living things that are considered in the study of life are cellular organization, metabolism, homeostasis, reproduction and heredity. **Cellular Organization** All cells have the same basic structure: a membrane that encloses the cell and controls materials that move in and out; an internal fluid known as the cytoplasm where the organelles are suspended; and nucleus that contains the hereditary genes called DNA. Organisms can either be made up of only one cell (unicellular) or made up of many cells (multicellular) Examples: - Amoeba, a unicellular organism - Ducklings, multicellular organisms **Metabolism** The sum of all chemical processes that maintain the living state of an organism is called metabolism. All organisms use energy to grow and all organisms transport this energy from one place to another within cells using special energy-carrying molecules called ATP. **Homeostasis** All living things maintain stable internal conditions. While the environment often varies a lot, organisms act to keep their interior conditions relatively constant in a process called homeostasis. The human body maintain an internal temperature of 37°C (98.5°F), however hot or cold the weather may be. **Reproduction** Reproduction involves the transfer of genetic information from parents to offspring. - Asexual Reproduction - produces offspring that are genetically identical to a single parent. - Sexual Reproduction - involves two parents contributing genetic information to produce a unique offspring. **Heredity** - The information that determines what an individual organism will be like is written in a code dictated by the sequence of the DNA molecule. Each set of instruction within the DNA is called a gene. - The transmission of characteristics from parent to offspring is called heredity. **Unifying Themes in Life Science** Life Science is unified by certain themes. These six general themes are levels of organization, the flow of energy, evolution, interacting systems, structure and function, ecology and science and society. **Lesson III: Cell: The Basic Unit of Life** The cell is the smallest structural and functional unit of life. It is considered the building block of all living organisms. - **Types of Cells**: - **Prokaryotic Cells**: Simple, smaller cells without a nucleus. Example: Bacteria. - **Eukaryotic Cells**: Complex cells with a defined nucleus and membrane-bound organelles. Examples: Plant and animal cells. **Importance of Cells**: - Basis of all life forms, providing structure to organisms. - Responsible for carrying out essential life processes like metabolism, growth, and reproduction. **History of Cell Discovery** - Observed cork under a microscope and coined the term \"cell\" to describe the tiny, box-like structures he saw. - Used a single-lens microscope to observe living cells (like bacteria and protozoa) and termed them \"animalcules.\" - Proposed that all plants are made up of cells. - Stated that all animals are made of cells, laying the groundwork for the **Cell Theory**. - Proposed that all cells arise from pre-existing cells, which added the third part to the Cell Theory. **Cell Theory**: 1. All living organisms are composed of one or more cells. 2. The cell is the basic unit of structure and function in organisms. 3. All cells arise from pre-existing cells. **Cell Organelles and Their Functions** Organelles are specialized structures within eukaryotic cells that perform distinct functions. Here's a list of major cell organelles: 1. **Nucleus** - Contains the cell\'s genetic material (DNA) and controls cellular activities. - **Components**: Nuclear envelope, nucleolus, and chromatin. 2. **Cell Membrane (Plasma Membrane)** - Protects the cell and controls the movement of substances in and out of the cell. - **Structure**: Phospholipid bilayer with embedded proteins. 3. **Cytoplasm** - Jelly-like substance that holds cell organelles and supports cellular functions. - **Components**: Cytosol (fluid) and various organelles. 4. **Mitochondria** - Known as the \"powerhouse of the cell,\" it generates ATP through cellular respiration. - **Unique Feature**: Has its own DNA. 5. **Endoplasmic Reticulum (ER)** - **Types**: - **Rough ER**: Studded with ribosomes; involved in protein synthesis. - **Smooth ER**: Lacks ribosomes; involved in lipid synthesis and detoxification. - **Function**: Transports synthesized proteins and lipids to various parts of the cell. Known as the "highway" of the cell. 6. **Golgi Apparatus** - Modifies, sorts, and packages proteins and lipids for transport. - **Structure**: Series of flattened sacs, often compared to a \"post office.\" 7. **Ribosomes** - Synthesize proteins. - **Location**: Found either floating in the cytoplasm or attached to the Rough ER. 8. **Lysosomes** (in animal cells) - Contains enzymes that digest waste materials and cellular debris. Known as the "suicide sac" of the cell. - **Importance**: Helps in breaking down macromolecules and old organelles. 9. **Chloroplasts** (in plant cells) - Site of photosynthesis, converting sunlight into chemical energy (glucose). Contains chlorophyll which is the green pigment of a plants. 10. **Vacuoles** - Storage of nutrients, waste products, and other substances. - **Size**: Larger in plant cells (central vacuole), smaller in animal cells. 11. **Centrioles** (mostly in animal cells) - Play a role in cell division by helping in the formation of the mitotic spindle. 12. **Cell Wall** (in plant cells, fungi, and some prokaryotes) - Provides structure, protection, and rigidity to the cell. - **Composition**: Mainly made of cellulose in plants. **Lesson III: Photosynthesis** **Photosynthesis** Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose, which can be used as food. This process takes place in the chloroplasts of plant cells and is essential for sustaining life on Earth by providing energy for most living organisms. **The process of photosynthesis occurs in two main stages:** **1. Light-Dependent Reaction (Thylakoid Membrane)** - **Purpose:** Capture light energy to produce ATP and NADPH, which are energy carriers used in the next stage. - **Location:** Thylakoid membrane of the chloroplast. - **Inputs:** Sunlight, Water (H₂O) - **Process:** - Sunlight excites electrons in chlorophyll molecules. - Water is split to release oxygen as a byproduct. - Energy from sunlight is used to convert ADP to ATP and NADP⁺ to NADPH. - **Outputs:** - **ATP** (energy carrier) - **NADPH** (electron carrier) - **Oxygen** (O₂) (byproduct released into the atmosphere) **2. Light-Independent Reaction (Calvin Cycle)** - **Purpose:** Use the ATP and NADPH produced in the light-dependent reactions to synthesize glucose. - **Location:** Stroma of the chloroplast. - **Inputs:** ATP, NADPH, Carbon Dioxide (CO₂), Water (H₂O) - **Process:** - Carbon dioxide is fixed into a stable intermediate and eventually converted into glucose. - ATP provides energy, and NADPH provides electrons for the synthesis of glucose. - **Outputs:** - **Glucose (C₆H₁₂O₆):** The main food source produced, which can be used immediately or stored. - **Oxygen:** Released as a byproduct. **Summary:** - **Light-Dependent Reactions** convert light energy into chemical energy (ATP and NADPH). - **Light-Independent Reactions (Calvin Cycle)** use ATP and NADPH to produce glucose. **Lesson IV: Plant Reproduction** **Introduction to Plant Reproduction** - Overview of asexual and sexual reproduction in plants - Importance of reproduction for plant survival and biodiversity **Anatomy of Flowering Plants (Basic Structure)** - **Sepals**: Protective layer for the bud - **Petals**: Attraction mechanism for pollinators - **Stamens and Carpels**: Primary reproductive structures **The Female Reproductive Part** - **Pistil** - **Stigma**: Receives pollen - **Style**: Connects stigma to ovary; pathway for pollen tube - **Ovary**: Contains ovules; site of fertilization - **Ovules**: Develop into seeds after fertilization - **Functions**: Capture pollen, fertilization, and seed development **The Male Reproductive Part** - **Stamen** - **Anther**: Produces pollen (male gametes) - **Filament**: Supports the anther - **Functions**: Pollen production and dispersal **Pollination Mechanisms** - **Definition of Pollination**: Transfer of pollen from anther to stigma - **Wind Pollination** - Characteristics of wind-pollinated plants (e.g., light, airborne pollen, exposed anthers and stigmas) - Examples: Grasses, conifers - **Insect Pollination** - Characteristics of insect-pollinated plants (e.g., bright petals, nectar, scents) - Role of insects (e.g., bees, butterflies) in transferring pollen - Examples: Sunflowers, orchids **Seed Dispersal Mechanisms** - **Purpose of Dispersal**: Reduce competition, colonize new areas - **Types of Dispersal** - **Wind Dispersal** - Characteristics: Lightweight seeds, winged or feathered structures - Examples: Dandelion, maple - **Self Dispersal** - Characteristics: Explosive mechanisms that propel seeds - Examples: Peas, balsam - **Water Dispersal** - Characteristics: Buoyant seeds or fruits that can float - Examples: Coconut, water lily - **Animal Dispersal** - Characteristics: Hooks or tasty fruit to attract animals - Examples: Berries (eaten by birds), burdock seeds (attach to fur) **Lesson V: Animal Production** **Introduction to Reproduction** - **Definition of Reproduction**: Fundamental biological process for species survival - **Importance of Reproduction**: Continuation of species, genetic diversity, adaptation **Overview of Reproduction in Animals** - **Asexual vs. Sexual Reproduction**: - **Asexual Reproduction**: Single parent, genetically identical offspring - **Sexual Reproduction**: Two parents, genetic variation in offspring - **Examples in Animals**: Common animals for each type **Modes of Reproduction in Animals** - **Oviparous** (Egg-laying): - Definition and examples (e.g., birds, fish, reptiles) - **Viviparous** (Live birth): - Definition and examples (e.g., mammals) - **Ovoviviparous** (Eggs hatch inside the mother): - Definition and examples (e.g., some sharks and reptiles) **Types of Asexual Reproduction in Animals** - **Budding**: - Process and examples (e.g., hydra, yeast) - Formation of new organism from the parent - **Fragmentation**: - Process and examples (e.g., starfish, flatworms) - Organism splits into parts, each regenerating into a new individual - **Regeneration**: - Process and examples (e.g., lizards regrowing tails, planaria) - Re-growth of lost or damaged body parts, sometimes leading to new individuals **Advanced Reproductive Techniques in Animals (Genetic Engineering)** - **Cloning**: - Definition and techniques (e.g., Dolly the sheep, somatic cell nuclear transfer) - Advantages, ethical considerations, and applications in agriculture and medicine - **Artificial Insemination**: - Definition and process (sperm collection, storage, and insertion into female) - Use in livestock breeding, benefits, and impact on genetic diversity