In-depth Notes on Genetics, Biology, and Ecosystems

Genetics: Study of heredity.
Heredity: Passing of traits from parents to offspring.
Innate behaviors: Instinctive behaviors performed from birth.
- Example: A dog drooling when it sees food.
Inherited traits: Characteristics passed from one generation to another (e.g., height, eye color).
Learned behaviors (Acquired traits): Traits influenced by experience/environment.
Influence of genes and environment: Most traits influenced by both genetics and the environment.

Human Chromosomes: Normal human cells contain 46 chromosomes, organized in 23 pairs.
- Autosomes: First 22 pairs, homologous chromosomes with same genes.
- Allosomes: 23rd pair, sex chromosomes (XX for females, XY for males).
Genotype: Unique DNA sequence (e.g., BB, Bb).
Phenotype: Detectable expression of genotype (e.g., physical traits like eye color).
Thomas Morgan: Discovered X and Y chromosomes in fruit flies in 1910.

Transformation: Some organisms can acquire new genetic properties from their environment.
Refers to bacteria taking up DNA from their environment, changing their characteristics.

Horizontal Gene Transfer: Process by which bacteria take up foreign DNA.
Plasmids: Small circular DNA separate from chromosomal DNA, valuable in recombinant DNA technology.
Restriction Enzymes: Enzymes that cut DNA at specific sites.
DNA Ligase: Enzyme that joins DNA fragments.

Mitosis: Division of a single cell into two identical daughter cells.
- Stages: Prophase, Metaphase, Anaphase, and Telophase (PMAT).
Meiosis: Division creating four non-identical sex cells, each with half the parent chromosomes.
Interphase: Pre-mitotic phase with three stages: G1 (first gap), S (synthesis), G2 (second gap).

DNA: Composed of nucleotides (sugar, phosphate, nitrogenous base).
- Bases: Adenine (A), Cytosine (C), Guanine (G), Thymine (T).
Central Dogma: Genetic information flows DNA -> RNA -> Protein.
Replication: DNA makes a copy during cell division.

Converts mRNA into a polypeptide (protein) at the ribosome.
- Codons in mRNA correspond to amino acids.

Mutation: Change in DNA sequence, which can be beneficial, harmful, or neutral.
Types of mutations include point mutations and frameshift mutations.
- Example: Sickle-cell anemia is a genetic disorder caused by point mutation.

Gradualism vs. Punctuated Equilibrium: Two models of evolution; gradualism suggests slow change, while punctuated equilibrium suggests rapid changes after periods of stability.
Natural Selection: Process where better-adapted organisms survive and reproduce.

Ecosystem: Interaction of biotic (living) and abiotic (non-living) factors in an environment.
Biomes: Large ecosystems characterized by climate, vegetation, and animal life.
Energy Pyramid: Represents energy transfer in a food chain; energy diminishes at each trophic level.

Adaptations are structures or behaviors enabling survival in an environment.
- Examples: Camouflage in animals, water storage in cacti.
Photosynthesis: Process by which plants use sunlight to convert carbon dioxide and water into glucose and oxygen.

Nervous System: Processes sensory information and coordinates responses.
Circulatory System: Transports nutrients and oxygen to cells, removes waste.
Respiratory System: Facilitates gas exchange between the body and the environment.
Endocrine System: Regulates physiological processes through hormones.

Complex interactions between genetic factors, environmental influences, evolutionary processes, and biological systems are essential for understanding life.