8 topics with a brief review: definitions, key facts, and classroom questions.
This section combines classical life-development theory with modern data on inheritance that does not affect the nucleotide sequence. Here, we analyze how the stages of organic evolution relate to individual development (epigenetics and ontogenesis) and how environmental factors shape new biological traits.
The material covers both traditional topics—population genetics, natural selection, adaptations, speciation, and macroevolution—and cutting-edge concepts. Special attention is paid to molecular mechanisms: DNA methylation, the paramutation phenomenon, and the epigenetic theory of evolution, which explains how organisms rapidly adapt to changing environmental conditions.
Seminars and colloquia most frequently address the molecular essence of methylation and the mechanisms of fixation of adaptations, and also require a clear distinction between the impact of classical natural selection and epigenetic factors on speciation and ontogenesis. Study the articles sequentially to gain a comprehensive understanding of the evolutionary process.
From whom did the first multicellular animals in this diagram descend?
Multicellularity arose thanks to ciliated protozoa (ciliates), from which multinucleated flatworms descended.
What is the triggering mechanism of evolution in this theory?
The process is triggered when a population enters unusual living conditions, which provokes disruptions in ontogenesis.
What is the essence of DNA methylation?
This is the attachment of a methyl radical to cytosine, which leads to a change in DNA conformation and the temporary blockade of activity in inactive genes within differentiated tissues.
Do individuals that received two mutant alleles of the Kit gene survive?
No, homozygotes for this mutation do not survive. The presence of two mutant alleles simultaneously leads to a lethal outcome.
What is the difference between prezygotic and postzygotic isolation?
Prezygotic isolation prevents the very formation of the zygote due to behavioral, ecological, or gametic barriers. Postzygotic isolation manifests after fertilization — hybrids turn out to be inviable or sterile.
To which form of selection does bacterial resistance to antibiotics belong?
This is a classic example of the directional form of natural selection. Environmental change (the introduction of an antibiotic) shifts the survival norm towards bacteria possessing resistance mutations.
Master the entire topic in the "Biology" course
This is a summary. The course covers everything tested in classes and exams.
3,793 pages of study guides across all topics
Assignments and quizzes after every topic — just like in a colloquium