Genetics and Heredity Overview

DNA

Heredity

Nucleotides

<p>DNA is a double-helix structure, composed of two strands of nucleotides that are twisted around each other. Each strand is made up of a sequence of nucleotides. The four types of nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). The two strands of DNA are held together by hydrogen bonds between the bases. Adenine binds to thymine, and guanine binds to cytosine. RNA or ribonucleic acid is a single stranded molecule that also contains genetic information. There are three types of RNA: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). mRNA is used to carry genetic information from the DNA to the ribosome (where protein synthesis takes place). tRNA carries amino acids to the ribosome. rRNA is a component of the ribosome, which is essential for protein synthesis.</p> Signup and view all the answers

<p>A genetic disorder is a condition that is caused by a change in a gene or genes. These changes can be inherited from parents or can occur spontaneously. There are many different types of genetic disorders, and they can affect any part of the body. Examples of genetic disorders are: cystic fibrosis, sickle cell anemia, Huntington's disease, and Down syndrome.</p> Signup and view all the answers

<p>The appendix is a small, finger-like projection that extends from the colon. Its function is not well understood, but it is thought to play a role in the immune system.</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>There are several theories about why dinosaurs became extinct, but the most widely accepted theory is that a large asteroid hit the Earth. This impact would have caused widespread devastation, including fires, earthquakes, and tsunamis. The resulting dust cloud would have blocked out the sun, leading to a global cooling event that would have made it difficult for dinosaurs to survive.</p> Signup and view all the answers

<p>Many species of animals and birds are becoming extinct due to habitat loss, over-hunting, climate change, invasive species, and pollution. These factors are making it difficult for some species to survive.</p> Signup and view all the answers

<p>The different organs in the body of organisms are: the heart, lungs, brain, stomach, intestines, liver, kidneys, skin, and bones.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Vestigial organs are organs that have no known function in a modern organism but were present and functional in its ancestors. Examples of vestigial organs in humans include:</p> <ul> <li>Appendix: The appendix is a small, finger-like projection that extends from the colon. It has no known function in humans, but it is thought to have been used by our ancestors to digest plant matter.</li> <li>Wisdom Teeth: Wisdom teeth are the third molars to erupt in the mouth. They are often impacted, meaning they do not erupt properly. They have no known function in humans.</li> <li>Tailbone (Coccyx): The coccyx is the small bone at the end of the spine. It is a remnant of the tail that our ancestors had. Some animals, such as monkeys and other primates, have a functional tail.</li> <li>Ear muscles: The ear muscles are used to move the ears. Humans have ear muscles, but they are not functional. Some mammals have ear muscles that are used to move their ears to help them hear better.</li> </ul> Signup and view all the answers

<p>Hereditary changes are changes in genetic material that are passed down from parents to offspring. These changes can be caused by mutations or by the process of genetic recombination. Mutations are changes in the DNA sequence. Genetic recombination is the process by which chromosomes exchange genetic material. These changes can create new traits that can be beneficial for survival in a changing environment. If these traits are advantageous, they are more likely to be passed down to the next generation and become more frequent in the population. Over time, this process can lead to the evolution of new species.</p> Signup and view all the answers

<p>Complex proteins are formed through a process called protein synthesis, which involves two main stages: transcription and translation. Transcription is the process of creating a messenger RNA (mRNA) molecule from a DNA template. This mRNA molecule then carries the genetic code for the protein to the ribosome. At the ribosome, translation occurs where the mRNA molecule is read and used to assemble amino acids into a polypeptide chain. The polypeptide chain then folds into a specific three-dimensional structure to form the functional protein.</p> Signup and view all the answers

<p>The theory of evolution states that all living organisms on Earth are descended from a common ancestor and that over time, these organisms have changed to become more adapted to their environment. This process of change is driven by natural selection, which is the process by which organisms that are better adapted to their environment are more likely to survive and reproduce. There is a vast amount of evidence to support the theory of evolution. This evidence comes from many different fields of study, including:</p> <ul> <li>Fossils: Fossils are the preserved remains of ancient organisms. They provide direct evidence of the evolution of life over time.</li> <li>Comparative anatomy: The study of similarities in the anatomy of different organisms shows that they share a common ancestor. For example, the bones of a human arm are homologous to the bones of a bat wing.</li> <li>Embryology: The study of embryos shows that different species share similarities in their early development. This suggests that they share a common ancestor.</li> <li>DNA: The genetic code of all living organisms is remarkably similar. This is further evidence that all life shares a common ancestor.</li> <li>Biogeography: The distribution of organisms on Earth is not random. Some organisms are found only in certain parts of the world. This pattern can be explained by the theory of evolution.</li> </ul> Signup and view all the answers

<p>Anatomical evidence provides insights into evolutionary relationships by examining the similarities and differences in the structures of organisms. For example, the forelimbs of humans, bats, whales, and dogs have a similar bone structure despite their different functions (arm, wing, flipper, paw). This suggests that they share a common ancestor and have evolved from the same basic structure. These shared structures are called homologous structures. The presence of homologous structures provides strong evidence for the shared ancestry of species and their evolutionary relationships.</p> Signup and view all the answers

<p>A fossil is the preserved remains or traces of an ancient organism. Fossils can include bones, teeth, shells, leaves, tracks, or even traces of ancient organisms like burrows or footprints. The fossil record is the history of life on Earth as documented by fossils. It is a valuable source of information about the evolution of life, showing how organisms have changed (morphologically) and become extinct over time. Fossils provide direct evidence of evolution by showing the existence of organisms that no longer exist and how they have changed. Fossils also show the sequence of life on Earth, revealing our planet's history of life. They also help scientists reconstruct earlier events in Earth's history and how the environment has changed over time.</p> Signup and view all the answers

<p>The evolution of modern humans is a complex process that has been ongoing for millions of years. The oldest known hominins, the group that includes humans and our extinct ancestors, appeared about 6 million years ago in Africa. Many different species of hominins evolved during this time, but only one species, Homo sapiens, survived. The earliest members of our own species appeared about 300,000 years ago in Africa. Modern humans began to migrate out of Africa around 100,000 years ago, eventually spreading to all parts of the world. Throughout the history of human evolution, several key adaptations have occurred. These include:</p> <ul> <li>Bipedalism: The ability to walk upright on two legs, which freed up the hands for other tasks.</li> <li>Enlarged brains: Our brains have become much larger than those of other primates, giving us the ability to think, learn, communicate, and solve problems.</li> <li>Complex social structures: We have complex social structures that allow us to cooperate and work together.</li> <li>Language: We have developed complex language that allows us to share information and ideas.</li> <li>Technology: We have invented tools and technologies that have allowed us to shape our environment and improve our quality of life.<br /> The evolution of modern humans is still ongoing. As we continue to evolve, we are developing new technologies and ways of thinking that will continue to change our world.</li> </ul> Signup and view all the answers

<p>principle</p> Signup and view all the answers

<p>genes</p> Signup and view all the answers

<p>transcription</p> Signup and view all the answers

<p>gradual development</p> Signup and view all the answers

<p>not</p> Signup and view all the answers

<p>Embryology</p> Signup and view all the answers

<p>Heredity is the passing of traits from parents to offspring. It involves the transmission of genetic material from one generation to the next. The mechanism of hereditary changes happens through natural selection which favors the traits providing more advantageous survival and reproduction for species in their environment.</p> Signup and view all the answers