Key Concepts in Biology

Cell Theory
- All living organisms are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Genetics
- DNA (deoxyribonucleic acid) carries genetic information.
- Genes are segments of DNA that code for proteins.
- Mendelian genetics explains inheritance patterns (dominant, recessive traits).
Evolution
- Natural selection is the mechanism for evolution, proposed by Charles Darwin.
- Species adapt to their environments over time.
- Common descent suggests all species share a common ancestor.
Homeostasis
- Organisms maintain stable internal conditions (temperature, pH, etc.).
- Feedback loops (positive and negative) regulate physiological processes.
Biochemistry
- Macromolecules: proteins, lipids, carbohydrates, nucleic acids.
- Enzymes are catalysts that speed up chemical reactions in cells.
- Metabolism includes all biochemical reactions within an organism (catabolism and anabolism).
Ecology
- Ecosystems consist of biotic (living) and abiotic (non-living) factors.
- Trophic levels: producers (autotrophs), consumers (heterotrophs), decomposers.
- Biomes are large geographic biotic communities (e.g. rainforest, desert).
Physiology
- Study of how organisms function.
- Major systems include circulatory, respiratory, digestive, and nervous systems.
- Homeostatic mechanisms like feedback loops control bodily functions.
Microbiology
- Study of microorganisms (bacteria, viruses, fungi).
- Key concepts include cell structure (prokaryotic vs. eukaryotic), reproduction (asexual vs. sexual), and pathogenicity.
Plant Biology
- Photosynthesis converts light energy into chemical energy (glucose).
- Vascular systems (xylem and phloem) transport water and nutrients.
- Plant hormones regulate growth and development.
Animal Behavior
- Studying how animals interact with their environment and each other.
- Key concepts include innate vs. learned behaviors, mating systems, and territoriality.
Biotechnology
- Genetic engineering involves manipulating an organism's DNA.
- Applications include CRISPR, cloning, and recombinant DNA technology.
Conservation Biology
- Focuses on preserving biodiversity and ecosystems.
- Strategies include habitat conservation, endangered species protection, and sustainable practices.

Cell Theory

All living things are made up of cells.
Cells are the fundamental unit of life.
All cells come from pre-existing cells, meaning they don't spontaneously form.

Genetics

DNA, or deoxyribonucleic acid, is the molecule of heredity.
DNA contains genes, which are specific sequences that hold the instructions for building proteins.
Mendelian genetics describes predictable inheritance patterns. These patterns follow simple rules, like dominant vs. recessive traits, allowing us to understand how characteristics are passed down.

Evolution

Charles Darwin proposed the theory of natural selection, which describes how species adapt to their environments.
Individuals with traits better suited for their environment are more likely to survive and reproduce, passing those traits on.
Common descent: All living organisms share a common ancestor, meaning we are all related.

Homeostasis

Organisms need to maintain stable internal conditions, like temperature and pH.
Feedback loops regulate these conditions.
Negative feedback loops counter changes, bringing things back to a set point. Positive feedback loops amplify changes, moving away from a set point.

Biochemistry

Macromolecules are large, complex molecules essential for life. Examples include proteins, lipids, carbohydrates, and nucleic acids.
Enzymes are biological catalysts, speeding up chemical reactions in cells.
Metabolism encompasses all biochemical reactions within an organism, including catabolism (breaking down molecules) and anabolism (building up molecules).

Ecology

Ecosystems encompass all living (biotic) and non-living (abiotic) components in an area.
Trophic levels describe feeding relationships: producers (autotrophs) make their own food, consumers (heterotrophs) eat others, and decomposers break down dead organisms.
Biomes are large geographical regions characterized by similar climate and dominant plant life. Examples include rainforests, deserts, and grasslands.

Physiology

Physiology focuses on how organisms function.
Major organ systems, like circulatory, respiratory, digestive, and nervous systems, work together.
Homeostatic mechanisms, like feedback loops, regulate these functions.

Microbiology

This field studies microorganisms, such as bacteria, viruses, and fungi.
Key concepts include the differences between prokaryotic (simple) and eukaryotic (complex) cells.
Microorganisms can reproduce asexually, by copying themselves, or sexually, through exchange of genetic material.
Pathogenicity refers to an organism's ability to cause disease.

Plant Biology

Photosynthesis is the process where plants convert light energy into chemical energy (glucose) using chlorophyll.
Vascular systems transport water and nutrients through plants. Xylem carries water upwards, while phloem carries sugars.
Plant hormones regulate growth and development.

Animal Behavior

This field studies how animals interact with their environment and each other.
Innate behaviors are genetically programmed, while learned behaviors are acquired through experience.
Mating systems describe how animals find mates and reproduce, including monogamy, polygamy, etc.
Territoriality involves defending an area, providing exclusive access to resources.

Biotechnology

Genetic engineering manipulates an organism's DNA.
Tools like CRISPR allow precise editing of genes.
Cloning makes identical copies of an organism.
Recombinant DNA technology combines DNA from different sources.

Conservation Biology

This field focuses on protecting biodiversity and ecosystems.
Strategies include protecting habitats, managing endangered species, and promoting sustainable practices.