Biology: Speciation and Evolution

Speciation

• Speciation is the formation of new species of plants and animals due to evolution
• A species is a group of organisms that can produce fertile individuals through natural reproduction
• Each species grows in specific geographical conditions, with unique food habits, habitat, reproductive ability, and period
• Genetic variation, geographical changes, and reproductive isolation can lead to the formation of new species
• These changes can result in the formation of new species from an existing one

Human Evolution

• The biodiversity we see today originated from simple unicellular organisms due to evolution
• The origin of human evolution can be traced back to the time when dinosaurs disappeared (approximately 70 million years ago)
• Monkey-like animals evolved from ancestors similar to modern lemurs in Africa
• These animals lost their tails around 40 million years ago and developed enlarged brains and improved hands, eventually evolving into ape-like animals
• Ape-like animals migrated to South and North-East Asia, evolving into gibbons and orangutans
• Remaining ape-like animals in Africa evolved into gorillas and chimpanzees around 25 million years ago
• Some ape species used their hands more for eating and other tasks, leading to further evolution

Journey of Human

• These ape-like animals started living on land as forests declined due to dry environments
• Their pelvic girdle developed, allowing them to stand upright in grasslands, making their hands available for use
• The first human-like animals with erect posture and using their hands evolved around 20 million years ago
• The first record of a human-like animal is Ramapithecus, found in North India and East Africa
• Over time, these apes grew in size, became more intelligent, and evolved into different species
• The evolution of Homo sapiens is marked by key milestones, including the emergence of ancient humans, Neanderthals, and Cro-Magnon man