A4.1 Evolution & Speciation

Vocabulary flashcards covering evolution and speciation concepts from the video notes.

Evolution

Change in heritable characteristics of a population over time.

Darwinism

Evolution by natural selection; proposed by Charles Darwin; natural selection is the mechanism.

Lamarckism

Acquired characteristics during an individual's lifetime are inherited; Lamarck's view is incorrect.

Natural selection

Mechanism of evolution where individuals with advantageous traits reproduce more, shifting allele frequencies.

Speciation

Formation of new species via splitting of pre-existing species.

Reproductive isolation

Barriers that prevent gene flow between populations, enabling speciation.

Allopatric speciation

Speciation due to geographic isolation.

Sympatric speciation

Speciation without geographic isolation.

Adaptive radiation

Rapid diversification of a lineage into many forms to fill vacant ecological niches.

Barriers to hybridization

Prezygotic or postzygotic barriers that prevent interbreeding between species; e.g., sterile interspecific hybrids like mules.

Polyploidy

A change in chromosome number involving multiple chromosome sets; common in plants and can cause abrupt speciation.

Homologous structures

Similar bone structures in different species due to common ancestry; e.g., pentadactyl limbs.

Pentadactyl limb

A five-digit limb pattern used as an example of limb homologues across vertebrates.

Analogous structures

Structures with the same function but different evolutionary origins.

Convergent evolution

Independent evolution of similar traits in unrelated lineages leading to analogous structures.

HOX genes

Homeobox genes that determine body plan during development; highly conserved across diverse animals.

DNA/RNA base sequences evidence

Comparing nucleotide sequences reveals evolutionary relationships; closely related species differ less.

Cytochrome c

A conserved protein used in molecular comparisons to study evolutionary relationships.

Selective breeding (domesticated animals and crops)

Variation between breeds and varieties shows rapid evolution under human selection.

Pragmatic truth (science)

In science, a theory is considered true if it works to explain and predict observations; evolution is treated as a pragmatic truth.

Antibiotic/pesticide resistance

Resistance evolves by natural selection; evidence for evolution.

Geographical isolation (Congo River example)

Geographic separation of populations (e.g., bonobos and common chimpanzees by the Congo River) leading to divergence.

Mule (sterile hybrid)

A sterile hybrid between horses and donkeys; an example of postzygotic reproductive isolation.

Abrupt speciation in plants via hybridization & polyploidy (knotweed)

Rapid origin of new species through hybridization and genome doubling, as seen in knotweed Persicaria.