Reproduction & Genetics
27 mechanisms in this category
Asexual Reproduction
Asexual reproduction copies an organism's entire genome identically. Bacteria divide this way. So do many plants, fungi, and some animals. One parent...
Chronotypes
Chronotypes are genetically-determined individual differences in circadian phase. Approximately 25% of the population are 'owls' (evening chronotype)...
DNA Repair Mechanisms
Cells maintain extraordinary reliability through redundant DNA repair mechanisms - multiple, partially overlapping pathways that detect and correct di...
DNA Replication
Every human alive today carries approximately three billion base pairs of DNA in nearly every cell. That information - encoded in just four chemical l...
DNA Replication Errors
DNA polymerase (the enzyme copying DNA during cell division) makes mistakes at a baseline rate. In bacteria, it's approximately 10^-10 errors per base...
Epigenetic Silencing
Epigenetic silencing involves chemical tags that silence genes without changing DNA sequence. In vernalization, cold triggers epigenetic changes that...
Epigenetics
Here's where reproduction gets truly subtle. For decades, biology taught that only DNA sequence determines inheritance - that acquired characteristics...
Genetic Redundancy
Genetic information exhibits redundancy through gene duplication and gene families - groups of genes with similar sequences and overlapping functions....
Genotype vs. Phenotype
This distinction between genotype (the information) and phenotype (the expression) is fundamental to understanding reproduction. It's also the most mi...
Germline vs. Somatic Distinction
The final critical concept: not all cells contribute to the next generation. Organisms divide their cells into two categories: somatic cells (body cel...
Good Genes Hypothesis
Some costly ornaments reliably correlate with genetic quality. The peacock's tail signals honest information - only healthy males can grow magnificent...
Horizontal Gene Transfer
Reproduction usually transfers genes vertically - from parent to offspring. But bacteria discovered a shortcut: horizontal gene transfer. They can acq...
Intersexual Choice
Female choice drives male investment in displays and courtship. Bower birds build elaborate structures, decorate them with blue objects, and perform d...
Intrasexual Competition
Male elephant seals fight each other directly for access to harems. The competition isn't about attracting females through displays - it's about defea...
Iteroparous Reproduction
Iteroparous reproduction (from Latin itero = repeat) is a reproductive strategy where organisms flower repeatedly, year after year, balancing growth a...
K-Selection
K-selection is nature's bet on stability. When environments are predictable - when the future resembles the past - evolution doesn't reward speed. It...
Mast Seeding
Oak trees exhibit synchronized mast seeding - massive acorn production (60 kg in mast year) alternating with minimal production (2 kg in recovery year...
Meiosis
Most cells divide through mitosis - copying the genome and splitting into two identical cells. But sex cells (sperm and eggs) are created through meio...
Molecular Clock Mechanism
The molecular clock is a transcription-translation feedback loop operating in each cell. Two proteins - CLOCK and BMAL1 - form a complex that binds to...
Protein Domain Architecture
Proteins are linear chains of amino acids that fold into three-dimensional shapes, and rather than each having a unique monolithic structure, most pro...
r-Selection
r-selection is nature's bet on chaos. When the future is unknowable - when environments shift faster than organisms can adapt - evolution doesn't rewa...
Recombination
Sexual reproduction shuffles existing genetic variants through meiotic recombination (crossover between homologous chromosomes). While not creating ne...
Runaway Selection
R.A. Fisher proposed in 1930 that some sexual selection creates self-reinforcing feedback loops unconnected to survival fitness. If females develop a...
Semelparous Reproduction
Semelparous reproduction (from Latin semel = once, pario = to beget) is a reproductive strategy where organisms reproduce once, then die. Century plan...
Semelparous vs Iteroparous
Semelparous organisms (Pacific salmon) reproduce once then die - 100% allocation to single reproductive event, zero resources to post-reproductive sur...
Sexual Reproduction
Sexual reproduction mixes genetic material from two parents. The offspring aren't copies - they're recombinations. The advantage: diversity. Each offs...
Transposable Elements
'Jumping genes' (transposons, retrotransposons) copy themselves and insert into new genomic locations, disrupting genes or regulatory sequences. Trans...