5 topics with brief reviews: definitions, key facts, and class questions.
Speciation is the central process of macroevolution, explaining how new isolates and distinct species arise from a single ancestral species.
In this section, we will analyze the classical forms of divergent speciation: allopatric (geographic) and sympatric (ecological). You will learn how trait divergence works at the genetic level and what genetic load is—whether it is an evolutionary ballast for a population or its hidden reserve. A separate block is dedicated to hominid evolutionary cytogenetics: we will trace which specific chromosomal rearrangements led to the formation of the Homo sapiens species.
In seminars and colloquia, you are most often asked to clearly distinguish between allopatric and sympatric speciation (with examples) and to explain the paradox of genetic load. Pay special attention to the chromosomal differences between humans and great apes—this is a classic examination question.
This is an indicator of the number of deleterious alleles in the genotype. Every human carries 3–5 recessive alleles that, in the homozygous state, lead to death before puberty.
What is divergent speciation in simple terms?
This is a process in which new species arise from a single ancestral species (divergence via the $A \rightarrow A + B$ scheme) due to the emergence of barriers and isolation within populations.
What initiates allopatric speciation?
The process always begins with the formation of a physical barrier (mountains, rivers, deserts, or a sharp change in population size) that divides the range of the original population.
Is a geographic barrier required for sympatric speciation?
No, the process occurs within a single range, inside a unified original population, without the formation of any physical barriers.
How many chromosome pairs does the normal karyotype of great apes contain?
In members of the Hominidae family (apes), the genetic apparatus consists of 24 pairs of homologous chromosomes, totaling 48.
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