Introduction to Biology and Scientific Method

Biology is the study of life, encompassing a broad range of topics from the smallest molecules to the largest ecosystems.
Key characteristics of life include organization, metabolism, growth, reproduction, adaptation, response to stimuli, and homeostasis.
Understanding biology involves studying the structure and function of living things at different levels of organization, from atoms to cells, tissues, organs, organ systems, organisms, populations, communities, and ecosystems.

The scientific method, used to investigate the natural world, involves observation, hypothesis formation, experimentation, data analysis, and conclusion.
A hypothesis is a testable explanation for an observation.
Experiments designed to test hypotheses need control groups and experimental groups to establish cause-and-effect relationships.
Data collected during experiments should be carefully recorded and analyzed, potentially statistically.
Conclusions are drawn based on analyzed data and may support or refute a hypothesis.
Scientific theories are well-supported explanations based on a large body of evidence and repeatedly tested hypotheses

Living organisms are composed of matter, which is anything that occupies space and has mass.
Matter is made of elements, which are substances that cannot be broken down into simpler substances by chemical means.
Atoms are the basic building blocks of matter, composed of protons, neutrons, and electrons.
The periodic table organizes elements according to their properties.
Molecules are formed by the bonding of atoms through interactions between valence electrons.
Water is a crucial molecule for life, and its properties, like polarity, high specific heat, and cohesion, are essential for biological processes.
Biological systems often employ organic molecules: carbohydrates, lipids, proteins, and nucleic acids.

Cells are the basic structural and functional units of all living organisms.
Cells have a variety of structures and functions that depend on their role in the organism or the environment it inhabits.
Prokaryotic cells are simple, lack a nucleus, and include bacteria and archaea.
Eukaryotic cells are more complex, contain a nucleus and other membrane-bound organelles, and include plants, animals, fungi and protists.
Cell membranes regulate the transport of materials into and out of cells.
Organelles like the mitochondria and chloroplasts perform specific functions within a cell.

Cellular respiration is the process by which cells break down glucose to release energy in the form of ATP (adenosine triphosphate).
Photosynthesis is the process by which plants and some other organisms use light energy to synthesize sugars from carbon dioxide and water.
Cellular reproduction (mitosis and meiosis) enables the growth and development or asexual and sexual reproduction of organisms.
Processes like transcription and translation are fundamental for gene expression and protein synthesis.

Genes are the units of heredity that determine traits.
DNA is the molecule that carries genetic information, encoded in its sequence of nucleotides (adenine, thymine, cytosine, and guanine).
DNA replication ensures accurate transmission of genetic information during cell division.
RNA carries out various functions, including protein synthesis.
Mutations are changes in DNA sequences, which can sometimes affect an organism's traits.
Genetic variation arises from mutations, meiosis, and sexual reproduction.

Evolution is the process of change in heritable characteristics of biological populations over successive generations.
Natural selection is the process by which organisms with advantageous traits tend to survive and reproduce at higher rates than others.
Evidence for evolution comes from fossil records, comparative anatomy and embryology, and molecular biology.
Adaptation describes how an organism or species becomes better suited to its environment over time.
Biodiversity is the variety of life on Earth at all its levels, from genes to ecosystems.

Ecology is the study of interactions between organisms and their environment.
Ecosystems consist of living (biotic) and non-living (abiotic) components.
Energy flows through ecosystems via food chains and food webs.
Nutrient cycles play a crucial role in maintaining ecosystem health.
The interactions between organisms and their environment influence the distribution and abundance of species.
Population dynamics and community interactions are crucial aspects of ecology.
Biomes are large terrestrial regions characterized by their climate and vegetation.