Introduction to Biology

• Biology is the scientific study of life, encompassing topics from microscopic processes within cells to ecosystem interactions.

Characteristics of Life

• Living organisms exhibit key characteristics.
• Order: Organisms possess highly organized structures.
• Sensitivity or Response to Stimuli: Organisms respond to environmental changes.
• Reproduction: Organisms create new organisms through reproduction.
• Adaptation: Organisms evolve adaptations for their environment.
• Growth and Development: Organisms grow and develop via genetic information.
• Regulation/Homeostasis: Organisms maintain stable internal conditions.
• Energy Processing: Organisms use energy to power activities.
• Evolution: Populations of organisms evolve over time.

Levels of Biological Organization

• Life is organized into a hierarchy of levels.
• Molecules: Atoms combine to form molecules.
• Organelles: Molecules form organelles, which are functional components of cells.
• Cells: The basic unit of life.
• Tissues: Groups of cells performing similar functions.
• Organs and Organ Systems: Organs are composed of tissues and perform specific functions; organ systems consist of multiple organs working together.
• Organisms: Individual living entities.
• Populations: Groups of individuals of the same species in an area.
• Communities: Populations of different species in an area.
• Ecosystems: Communities and their physical environment.
• Biosphere: All ecosystems on Earth.

Cell Structure and Function

• The cell is the basic unit of life.
• Cells are either prokaryotic or eukaryotic.
• Prokaryotic cells lack a nucleus and complex organelles.
• Eukaryotic cells possess a nucleus and membrane-bound organelles.
• Nucleus: Contains the cell's DNA.
• Ribosomes: Synthesize proteins.
• Endoplasmic Reticulum (ER): Involved in protein and lipid synthesis.
• Golgi Apparatus: Processes and packages proteins.
• Mitochondria: Generate ATP through cellular respiration.
• Lysosomes: Contain enzymes for breaking down cellular waste.
• Plasma Membrane: The outer boundary of the cell, controls entry and exit.

Genetics and Heredity

• Genes, composed of DNA, are the units of heredity.
• DNA (deoxyribonucleic acid) carries genetic information.
• Chromosomes are structures containing DNA.
• Genes encode instructions for building proteins.
• Genotype: Genetic makeup of an organism.
• Phenotype: Observable characteristics influenced by genotype and environment.
• Inheritance: Transmission of traits from parents to offspring.
• Meiosis: Cell division that produces gametes (sperm and egg cells) with half the number of chromosomes.
• Fertilization: Fusion of gametes to restore the full chromosome number and create a new organism.

Evolution

• Evolution is the process of change in species characteristics over generations.
• Natural selection is a primary mechanism; advantageous traits become more common in a population.
• Charles Darwin proposed the theory of evolution by natural selection.
• Adaptation: A trait that improves survival and reproduction in a specific environment.
• The fossil record shows the history of life to evidence evolution.
• Comparative anatomy shows structural similarities between species to evidence evolution.
• Embryology shows similarities in embryonic development to evidence evolution.
• Molecular biology shows similarities in DNA and protein sequences to evidence evolution.
• Biogeography, examining species distribution on Earth, evidences evolution.

Ecology

• Ecology is the study of interactions between organisms and their environment.
• Population: A group of individuals of the same species in the same area.
• Community: All populations of different species in the same area.
• Ecosystem: A community of organisms in an area and their physical environment.
• Biosphere: The sum of all ecosystems on Earth.
• Trophic Levels describe the feeding positions in an ecosystem.
• Producers: Autotrophs, produce their own food (e.g., plants).
• Consumers: Heterotrophs obtain energy by consuming other organisms.
• Decomposers: Break down dead organisms and waste.
• Food chains and food webs: Show the flow of energy and nutrients through an ecosystem.
• Biogeochemical cycles: The movement of elements (e.g., carbon, nitrogen, water) through ecosystems.

Plant Biology

• Plants are multicellular, eukaryotic organisms.
• Photosynthesis: Plants convert light energy into chemical energy (sugars).
• Roots: Anchor the plant and absorb water and nutrients.
• Stems: Support the plant and transport water and nutrients.
• Leaves: Sites of photosynthesis.
• Flowers: Reproductive structures.
• Vascular tissue transports water and nutrients for plant adaptation to terrestrial life.
• The cuticle, a waxy layer, prevents water loss as a plant adaptation to terrestrial life.
• Stomata are pores for gas exchange as a plant adaptation to terrestrial life.
• Pollination is the transfer of pollen from the stamen to the pistil in plant reproduction.
• Fertilization is the fusion of sperm and egg to form a zygote in plant reproduction.
• Seed dispersal spreads seeds to new locations in plant reproduction.

Animal Biology

• Animals are multicellular, eukaryotic organisms.
• Animals are heterotrophic, obtaining energy by consuming other organisms.
• Most animals can move.
• Reproduction is primarily sexual in animals.
• Specialized tissues include nervous, muscle, epithelial, and connective tissues.
• Invertebrates are animals without a backbone.
• Vertebrates are animals with a backbone.
• The nervous system coordinates body functions through electrical and chemical signals.
• The endocrine system regulates body functions through hormones.
• The circulatory system transports blood, oxygen, and nutrients.
• The respiratory system exchanges gases with the environment.
• The digestive system breaks down food for absorption.
• The excretory system removes waste products.
• The immune system protects the body from pathogens.
• The reproductive system is involved in reproduction.

Microbiology

• Microbiology is the study of microorganisms, including bacteria, archaea, viruses, fungi, and protists.
• Bacteria are prokaryotic, single-celled organisms.
• Archaea are prokaryotic organisms, often living in extreme environments.
• Viruses are non-cellular entities requiring a host cell to replicate.
• Fungi are eukaryotic organisms, including yeasts, molds, and mushrooms.
• Protists are eukaryotic organisms, mostly unicellular.
• Microorganisms play roles in nutrient cycling as decomposers break down organic matter.
• Microorganisms play roles in disease when pathogens cause infectious diseases.
• Microorganisms used in food production, medicine, etc in biotechnology.

Biotechnology

• Biotechnology uses biological systems, organisms, or their parts to develop or create different products.
• Genetic engineering modifies an organism's genetic material.
• Cloning creates genetically identical copies of an organism.
• Polymerase chain reaction (PCR) amplifies DNA.
• Medicine: Developing new drugs and therapies uses biotechnology.
• Agriculture: Creating genetically modified crops uses biotechnology.
• Environmental science: Bioremediation of pollutants uses biotechnology.
• Forensics: DNA fingerprinting for identification uses biotechnology.