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Definition of Evolution: Change in the heritable characteristics of a species over time.
- Change occurs due to random mutations in genes.
- Evolution is unpredictable and has no specific direction.
- Non-heritable or acquired traits cannot be passed to offspring.

Fossil Record: Shows progressions of life forms from simple to complex.
Biogeographical Evidence: Distribution of species aligns with common ancestry and environmental adaptation.
Anatomical Evidence: Structures that indicate shared ancestry (homologous and analogous structures).
Developmental Evidence: Similarities in embryonic development across species.
Biochemical Evidence: Molecular similarities, including DNA, RNA, and proteins.
Genomic Evidence: Chromosomal similarities across different species.

Distribution of organisms is due to inheritance from common ancestors affected by plate tectonics.
Adaptation to unique environments leads to genetic changes in separated populations.

Homologous Structures: Similar body parts due to shared ancestry but may serve different functions (e.g., limb bones in vertebrates).
Analogous Structures: Structures with similar functions but evolved independently (e.g., wings of insects vs. birds).
Vestigial Structures: Inherited structures with no current function (e.g., the human ear muscles).

Shared characteristics in embryos of various species reveal common ancestry.
Similar developmental stages observed, e.g., vertebrate embryos have notochords and somites at certain stages.

Molecular similarities among DNA and proteins indicate a common genetic heritage.
Comparisons of genetic code allow estimation of divergence times among species.

Humans do not evolve from apes; instead, we share a common ancestor with them.
Genetic similarity: 1.3% single base-pair substitutions exist between humans and chimps.

Human chromosomes (2n=46) differ from those of other great apes (2n=48), indicating evolutionary divergence.
Human chromosome 2 arose from the fusion of two ancestral chromosomes.

Evolution: Change in allele frequency in a population over time.
Evolutionary Forces: Factors that alter allele frequencies (e.g., genetic drift, mutation).

Mutation: Source of new alleles important for variation.
Genetic Drift: Random changes in allele frequency; significant in small populations.
- Bottleneck Effect: Sudden decrease in population size reduces genetic variation.
- Founder Effect: New population starts with a smaller gene pool, leading to reduced variability.
Gene Flow: Introduction of new alleles through migration increases genetic variation.
Natural Selection: Favors advantageous traits — beneficial variations proliferate, whereas harmful traits are selected against.
Non-Random Mating: Influences reproductive success and can affect allele frequency.

Organisms exhibit variations, which can be hereditary.
Variants can be stable, harmful, or beneficial, influencing survival and reproduction.
The environment plays a critical role in determining which variants are favored.

Stage 1: Inorganic molecules formed complex structures.
Stage 2: Development of RNA as a replicator; RNA structures evolved to facilitate replication.
Stage 3: Emergence of cellular life, wherein replicating molecules became encapsulated within lipid structures, forming protocells.

The Last Universal Common Ancestor (LUCA) is hypothesized to be the starting point for all life, leading to prokaryotes and subsequently eukaryotes.
Cooperation among cells was a significant evolutionary transition toward multicellularity.

Evolutionary adaptations are ongoing, with evidence of genetic modifications in response to environmental pressures (e.g., high altitude adaptations in Tibetans).
Humans, as a species, represent diverse adaptations to different environments.