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Evolution One Shot | Part 2 | Fast Track NEET 2024 | Seep Pahuja

Unacademy NEET・95 minutes read

The text covers the Evolution chapter for Class 12, focusing on genetics, NEET application instructions, Lamarckism theory, Darwin's theory of natural selection, Hardy Weinberg equilibrium, and the evolution of various species from reptiles to humans. It also highlights the importance of understanding genetic inheritance, adaptability, and environmental changes in evolutionary processes.

Insights

Lamarckism theory suggests acquired traits can be inherited, such as a giraffe's stretched neck, but not all acquired traits pass on to the next generation.
Darwin's theory of natural selection emphasizes survival advantages through positive variations and adaptation to the environment, critiqued for lacking an understanding of mutations.
Hardy Weinberg principle states that populations in equilibrium show constant allelic frequencies, with factors like genetic drift and natural selection influencing gene pools and evolution.

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What is Lamarckism theory?
Lamarckism theory suggests acquired traits can be inherited.

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Summary

00:00

NEET Application Form Instructions and Evolution Theories

The chapter discussed is Evolution, belonging to Class 12th, focusing on genetics and Evolution.
The session was delayed due to the introduction of NEET 2024 Application Forms, which needed to be filled out.
Detailed instructions were provided on how to fill out the NEET application form, including uploading photos and necessary documents.
Emphasis was placed on the importance of correctly uploading a passport-sized photo with specific requirements.
Reservation categories like General, EWS, OBC, SC, and ST were mentioned for the application process.
Instructions were given on how to edit and upload a photo for the NEET application, ensuring compliance with guidelines.
The Lamarckism theory was discussed, highlighting the concepts of Use and Disuse Theory and Inheritance of Acquired Character.
Lamarck's theory suggested that acquired characteristics could be passed on to the next generation, using the example of a giraffe stretching its neck to reach leaves.
The theory of Inheritance of Acquired Character was explained, indicating that not all acquired traits are passed on to the next generation.
Practical advice was given on how to correctly upload photos for the NEET application, emphasizing the importance of following guidelines precisely.

15:39

"Essential Changes for Generational Inheritance"

Learning a good song is emphasized, with no need for acting skills.
Changes necessary for passing on traits to the next generation are discussed.
The importance of changes in somatoplasm or germ plasma for generational transfer is highlighted.
The role of DNA changes in somatic cells for generational inheritance is explained.
The experiment by scientist August Weissman involving tail cutting in mice is detailed.
The conclusion that changes in germ plasm are essential for inheritance of acquired traits is drawn.
The theory of natural selection by Darwin and Alfred Wallace is introduced.
Darwin's observations on artificial selection in crops and its relation to natural selection are discussed.
The theory of natural selection emphasizes the struggle for existence and variations for survival advantage.
The importance of positive variations and adaptation to the environment for success in competitive scenarios is stressed.

32:27

"Evolution, Fitness, and Mutation Theories Explained"

Children are referred to as "survival of the fittest" and nature plans for the fittest to succeed.
Fit individuals are chosen to become doctors, while unfit people are deemed unsuitable for other roles.
The concept of fitness is discussed in relation to natural selection and reproductive fitness.
Darwin's theory of natural selection is explained, focusing on branching descent and natural selection as key points.
Darwin's theory is critiqued for lacking an understanding of mutation and the source of variation.
Hugo De Vries introduced the mutation theory, emphasizing sudden large inheritances as the source of variation.
Mutation theory contrasts with Darwin's variation theory, highlighting sudden, large, and potentially beneficial changes.
De Vries proposed that mutations could lead to the creation of new species in a single step, known as saltation.
Practical advice is given on the number of postcard-sized photos to take, suggesting a minimum of 10 for optimal results.
The industrial melanism example is used to illustrate the impact of industrialization on tree pigmentation and the presence of pollutants like SO2.

49:28

Industrialization Shifts Bird Mouth Color Evolution

Dark Wing Mouth observed to be smaller compared to industrial First Light Wing Mouth.
Industrialization led to an increase in melanin in the mouth, resulting in a darker color.
Melanin content in the mouth increased due to industrialization, causing a shift from light to dark.
Nature selected dark-mouthed birds post-industrialization due to environmental changes.
Herbicide and pesticide use resulted in the selection of resistant variants in organisms.
Evolution by anthropogenic action led to the rapid emergence of resistant varieties.
Resistance to antibiotics and herbicides developed in organisms over shorter time scales.
Evolution is not a deterministic process but based on chance events and mutations.
Variations in bacteria populations occur based on their ability to adapt to new conditions.
Fitness in organisms is determined by genetic inheritance and adaptability to survive in changing environments.

01:05:05

Hardy Weinberg Principle and Genetic Drift

Hardy Weinberg principle applies to populations, not individuals
It states that if a population is in equilibrium, evolution has not occurred
In equilibrium, the allelic frequency remains constant
The gene pool in a population also remains constant if evolution has not occurred
The equation for Hardy Weinberg equilibrium is p^2 + 2pq + q^2 = 1
Factors affecting Hardy Weinberg equilibrium include mutation, recombination, genetic drift, natural selection, and gene migration
Genetic drift can lead to sudden changes in gene frequency in small populations
The Founder Effect and Bottleneck Effect are examples of genetic drift
The Founder Effect occurs when a small group establishes a new population
The Bottleneck Effect results from a drastic reduction in population size
Natural selection can lead to stabilizing, directional, or disruptive selection based on average traits or extremes in a population

01:22:22

Evolutionary Journey: Reptiles to Modern Birds

Practice sessions with questions will be held on consecutive days, including today, tomorrow, and the day after.
Tomorrow's class will focus on Hardy Weinberg's Equilibrium, with a half-hour session.
The session will include various numerical problems related to Hardy Weinberg's Equilibrium.
The class will cover the evolution timeline, starting from non-cellular forms to multicellular organisms.
Evolutionary history will be discussed, including the emergence of vertebrates and invertebrates.
Reptiles will be highlighted as the first true land vertebrates, with a focus on their successful reproduction due to thick egg cuticles.
The evolution of reptiles will be illustrated through a flow chart, showcasing the transition from early reptiles to modern-day reptiles and birds.
The diagram will depict the evolutionary journey of reptiles, including the emergence of dinosaurs and modern birds from early reptiles.
The session will emphasize the significance of sauropsids and synapsids in the evolution of birds and modern reptiles.
Notable reptiles like Ethio Sauras and dinosaurs, such as Tyrannosaurus Rex, will be discussed, highlighting their unique characteristics and evolutionary significance.

01:37:44

Evolution of Life on Earth: A Timeline

Triceratops existed on Earth around 65 million years ago, dominating the planet 200 million years ago.
Dinosaurs suddenly disappeared 65 million years ago, with a possible link to climate change.
Some dinosaurs evolved into birds, leading to the extinction of large reptiles and the survival of small reptiles like lizards.
The evolution of mammals followed the extinction of large reptiles, with early mammals resembling shrews.
The first mammals dominated the Earth after reptiles, with South America being a significant region for mammal evolution.
Pouch mammals in Australia survived due to lack of competition, leading to minimal evolutionary changes.
The evolution of humans began with primates like Ramapithecus and Australopithecus in Eastern Africa.
Homo habilis was the first human-like hominid with a brain capacity of 650 to 800 cc and likely a vegetarian diet.
Homo erectus emerged 1.5 million years ago in Java, with a brain capacity of 900 cc and a meat-eating diet.
Neanderthal man with a brain size of 1400 cc appeared in Near East and Central Asia, showcasing cultural practices like body protection and burial rituals.

01:53:24

"Evolution of Homo sapiens through history"

Homo sapiens evolved from Africa to different continents, with human evolution occurring 25,000 to 10,000 years ago.
Prehistoric cave art, such as the paintings in Bim Bedka Rock Shelter in Madhya Pradesh, provides insights into ancient cultures and human activities from 18,000 years ago.
Agriculture appeared 10,000 years ago, with significant rock paintings like the Bedka paintings in MP showcasing historical developments.
Human evolution traces back to 50 million years ago, with various species like Australopithecus and Homo erectus exhibiting distinct characteristics and cultural practices.
Modern human evolution is compared to baby chimpanzees and adult chimpanzees, highlighting similarities and differences in skull structures, emphasizing the evolutionary journey of Homo sapiens.

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