Biology Chapter 7: Evolution

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Questions and Answers

What is the primary focus of Evolutionary Biology?

The study of the history of life forms on earth.

The Big Bang theory attempts to explain the origin of life on earth.

False

What did Louis Pasteur's experiments demonstrate regarding the origin of life?

Life arises from non-living matter.

Life can spontaneously generate.

Life originates from outer space.

Life comes only from pre-existing life. (correct)

Fossils are remains of hard parts of __________ found in rocks.

life-forms Signup and view all the answers

Match the following terms with their definitions:

Homology = Structures derived from a common ancestor Analogy = Structures with similar functions but different origins Divergent evolution = Similar structures due to adaptation to different needs Convergent evolution = Different structures evolving for the same function Signup and view all the answers

What did Hugo deVries believe causes evolution?

Mutations Signup and view all the answers

According to Mendel, inheritable factors influence phenotype.

True Signup and view all the answers

In a diploid, the frequency of allele A is represented by and allele a is represented by .

p, q Signup and view all the answers

What is the Hardy-Weinberg principle used for?

The Hardy-Weinberg principle is used to find out the frequency of alleles of a gene in a population and states that allele frequencies remain stable across generations. Signup and view all the answers

Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.

Antibiotic resistance in bacteria can be explained by the process of natural selection proposed by Darwin. When bacteria are exposed to antibiotics, those with genetic mutations that provide resistance to the antibiotic will survive, reproduce, and pass on these resistance genes to their offspring. Over time, this leads to the development of more antibiotic-resistant bacterial populations. Signup and view all the answers

Match the following evolutionary stages with their descriptions:

Australopithecines = Hunted with stone weapons and primarily ate fruit Neanderthal man = Lived in near east and central Asia, used hides to protect body, buried their dead Homo sapiens = Arose in Africa, moved across continents, and developed into distinct races Signup and view all the answers

Describe one example of adaptive radiation.

One example of adaptive radiation is the finches on the Galapagos Islands studied by Charles Darwin. These finches adapted to different ecological niches on different islands, leading to the development of various beak shapes and sizes to exploit different food sources. Signup and view all the answers

Attempt giving a clear definition of the term species.

A species is a group of organisms that can interbreed and produce fertile offspring. Members of the same species share similar characteristics and are able to reproduce within their group, but typically not with members of other species. Signup and view all the answers

Can we call human evolution as adaptive radiation?

Human evolution is not typically classified as adaptive radiation. Adaptive radiation refers to the rapid diversification of a single ancestral species into multiple different species to exploit diverse ecological opportunities. Human evolution involves gradual changes over long periods and does not fit the criteria for adaptive radiation. Signup and view all the answers

What is another example of analogy provided in the text?

Sweet potato (root modification) and potato (stem modification) Signup and view all the answers

What supports evolution by natural selection based on the example from England?

Predators will spot a moth against a contrasting background Signup and view all the answers

Evolution is a directed process.

False Signup and view all the answers

What are the two key concepts of Darwinian Theory of Evolution?

Natural selection Signup and view all the answers

Adaptive radiation refers to the process of evolution of different species in a given geographical area starting from a point and radiating to other areas of geography, also known as ________.

convergent evolution Signup and view all the answers

Study Notes

Origin of Life

The origin of life is considered a unique event in the history of the universe.
The universe is vast and approximately 20 billion years old.
The Big Bang theory attempts to explain the origin of the universe.
The Earth was formed about 4.5 billion years ago, and there was no atmosphere on early Earth.
Water vapor, methane, carbon dioxide, and ammonia released from the molten mass covered the surface.
The UV rays from the sun broke up water into Hydrogen and Oxygen, and the lighter H2 escaped.
Oxygen combined with ammonia and methane to form water, CO2, and others.
The ozone layer was formed, and as it cooled, the water vapor fell as rain, filling all the depressions and forming oceans.
Life appeared 500 million years after the formation of Earth, approximately 4 billion years ago.

Chemical Evolution

The first form of life could have come from pre-existing non-living organic molecules (e.g., RNA, protein, etc.).
The formation of life was preceded by chemical evolution, i.e., the formation of diverse organic molecules from inorganic constituents.
The conditions on Earth were - high temperature, volcanic storms, reducing atmosphere containing CH4, NH3, etc.
In 1953, S.L. Miller created similar conditions in a laboratory scale, observing the formation of amino acids and other organic compounds.

Evolution of Life Forms

The theory of special creation suggests that all living organisms were created as such, with diversity being the same since creation.
Charles Darwin concluded that existing living forms share similarities to varying degrees not only among themselves but also with life forms that existed millions of years ago.
There has been gradual evolution of life forms, with a population having built-in variation in characteristics.
Those characteristics that enable some to survive better in natural conditions would outbreed others, leading to natural selection.
Fitness refers to reproductive fitness, and those who are better fit in an environment leave more progeny than others.

Evidences for Evolution

Fossils are remains of hard parts of life-forms found in rocks, indicating the arrangement of sediments one over the other during the long history of Earth.
Comparative anatomy and morphology show similarities and differences among organisms of today and those that existed years ago.
Homology indicates common ancestry, whereas analogy refers to a situation where different structures evolve for the same function.
Biochemical similarities point to the same shared ancestry as structural similarities among diverse organisms.

Adaptive Radiation

Adaptive radiation is the process of evolution of different species in a given geographical area starting from a point and radiating to other areas of geography (habitats).
Darwin's finches represent one of the best examples of this phenomenon, with different varieties of finches evolving from the original seed-eating features.
Australian marsupials and placental mammals in Australia also exhibit adaptive radiation, evolving into varieties each of which appears to be 'similar' to a corresponding marsupial.

Biological Evolution

Evolution by natural selection would have started when cellular forms of life with differences in metabolic capability originated on Earth.
The rate of appearance of new forms is linked to the life cycle or life span.
Microbes that divide fast have the ability to multiply and become millions of individuals within hours.
A change in the medium composition would bring out only that part of the population that can survive under the new conditions.### Evolution
Evolution is a process that leads to the formation of new species over time.
It occurs through the selection of individuals with favorable traits, leading to adaptation and survival in a changing environment.

Mechanism of Evolution

Variation in a population is the raw material for evolution.
There are five factors that affect Hardy-Weinberg equilibrium: gene migration, genetic drift, mutation, genetic recombination, and natural selection.
Natural selection is the process by which heritable variations enabling better survival and reproduction are favored.

Natural Selection

It is a process that leads to the survival and reproduction of individuals with favorable traits.
There are three types of natural selection: stabilizing, directional, and disruptive selection.
Stabilizing selection leads to the formation of a population with a mean character value.
Directional selection leads to the formation of a population with a value other than the mean character value.
Disruptive selection leads to the formation of a population with extreme values.

Evolution of Life on Earth

The first cellular forms of life appeared on earth around 2000 million years ago.
The earliest life forms were single-celled organisms that evolved into multi-cellular life forms.
Around 500 million years ago, invertebrates were formed, and by 350 million years ago, jawless fish had evolved.
Plants were the first organisms to invade land, and animals later followed.

Evolution of Vertebrates

The first vertebrates were fish-like organisms that evolved into amphibians.
Amphibians evolved into reptiles, which laid thick-shelled eggs.
Reptiles dominated the earth for 200 million years and then disappeared.
Mammals evolved from small, shrew-like reptiles and took over the earth.

Evolution of Man

The earliest human-like primates walked upright in eastern Africa around 3-4 million years ago.
The first human-like being, Homo habilis, had a brain capacity of 650-800cc and did not eat meat.
Homo erectus had a larger brain capacity and probably ate meat.
Homo sapiens arose in Africa and migrated to other continents, developing into distinct races.

Summary

The origin of life on earth can be understood against the background of the origin of the universe.
Darwinian ideas of organic evolution by natural selection explain the diversity of life forms on earth.
The study of comparative anatomy, fossils, and comparative biochemistry provides evidence for evolution.

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Description

This quiz covers the origin of life, evolution of life forms, evidence for evolution, and adaptive radiation. Understand the history of life forms on earth and the context of origin of life.