Biology Chapter 6: Evolution

A set of vocabulary flashcards derived from the lecture notes on Evolutionary Biology, covering origins, theories of evolution, anatomical evidence, and the history of human ancestors.

Evolutionary Biology

The study of the history of life forms on earth.

Age of the Universe

It is almost $13.8$ billion years old.

Big Bang Theory

A theory attempting to explain the origin of the universe as a singular huge explosion that led to expansion, cooling, and the subsequent formation of Hydrogen and Helium.

Formation of Earth

Earth was supposed to have been formed about $4.5$ billion years back in the solar system of the milky way galaxy.

Panspermia

An idea favoured by some astronomers that units of life called spores were transferred to different planets, including earth, from outerspace.

Theory of Spontaneous Generation

The belief that life arose from decaying and rotting matter like straw and mud; a theory dismissed by Louis Pasteur.

Chemical Evolution

The proposal by Oparin and Haldane that the first form of life could have come from pre-existing non-living organic molecules and was preceded by the formation of diverse organic molecules from inorganic constituents.

Miller's Experiment

A $1953$ experiment by S.L. Miller where electric discharge in a closed flask containing $CH_4, H_2, NH_3$ and water vapour at $8000C$ resulted in the formation of amino acids.

Theory of Special Creation

A religious theory with Three connotations: all organisms were created as they are today, diversity has always been and will be the same, and the earth is about $4000$ years old.

Natural Selection

A mechanism of evolution suggested by Charles Darwin where individuals with characteristics that enable better survival in natural conditions leave more progeny and are selected by nature.

Paleontological Evidence

Evidence for evolution based on fossils, which are remains of hard parts of life-forms found in rock sediments of different ages.

Homologous Structures

Structures that share similar anatomical patterns but perform different functions, indicating common ancestry and divergent evolution, such as the forelimbs of whales, bats, Cheetah, and humans.

Analogous Structures

Structures that are not anatomically similar but perform similar functions due to convergent evolution, such as the wings of butterflies and birds or the flippers of Penguins and Dolphins.

Industrial Melanism

An observation from England where the proportion of white-winged moths to dark-winged moths reversed after industrialisation due to soot-covered tree trunks and predator selection.

Adaptive Radiation

The process of evolution of different species in a given geographical area starting from a point and radiating to other habitats, exemplified by Darwin's finches and Australian marsupials.

Mutation Theory

The idea proposed by Hugo deVries that evolution is caused by large, random, and directionless differences arising suddenly in a population.

Saltation

A term used by Hugo deVries to describe a single step large mutation as the cause of speciation.

Hardy-Weinberg Principle

A principle stating that allele frequencies in a population are stable and constant from generation to generation ($p^2+2pq+q^2=1$) in the absence of evolutionary disturbances.

Genetic Drift

A change in allele frequency that occurs by chance, which can lead to the founder effect if a new sample of population becomes a different species.

Coelacanth

A lobefin fish caught in South Africa in $1938$ that was previously thought to be extinct and is considered an ancestor of modern day amphibians.

Homo habilis

The first human-like hominid with brain capacities between $650\text{--}800\text{cc}$ who lived about $2\text{mya}$ and probably did not eat meat.

Homo erectus

A hominid fossil discovered in Java in $1891$ that existed about $1.5\text{mya}$ with a brain size of around $900\text{cc}$ and probably ate meat.

Neanderthal man

Hominids with a brain size of $1400\text{cc}$ who lived in near east and central Asia between $1,00,000\text{--}40,000$ years ago, used hides, and buried their dead.