Heredity and Evolution Test - 10

Hemophilia is a bleeding disorder that slows down the blood clotting process. People who have hemophilia often have longer bleeding after an injury or surgery.

Hemophilia is inherited in an X-linked recessive pattern. A condition is considered X-linked when gene mutation that causes it is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is enough to cause the condition. Since females have two X chromosomes, a mutation must be present in both copies of the gene to cause the hemophilia. Males are affected by X-linked recessive disorders much more frequently than females.

Genes are the units of heredity and are the instructions that make up the body's blueprint. They code for the proteins that determine virtually all of a person's characteristics. Most genes come in pairs and are made of strands of genetic material called deoxyribonucleic acid, or DNA.

In 1869, Johann Friedrich Miesner, a young Swiss medical student, discovered an acidic substance that he isolated from pus cells obtained from bandages used to dress humans. He found it in the form of a mixture of compounds in the nucleus of the cell and named it “Nuclein”. The nature of Nuclein was unusual as it contained large amounts of both nitrogen and phosphorous and at that time these two elements were known to coexist only in certain types of fats.

Even though the discovery of Nuclein by Meischer took quite early but the discovery of DNA as genetic material took very long to be discovered and proven

Biogenetic law, also called Recapitulation Theory, postulation, by Ernst Haeckel in 1866, that ontogeny recapitulates phylogeny—i.e., the development of the animal embryo and young traces the evolutionary development of the species.

Appendix is a functional and significant structure in herbivores even today. Non-functional but presence of appendix is a sign of being once functional and belonging to herbivores.

1. Cells functioning together form tissue and tissue in turn form organs.
2. organs with same origin but different function- homologous organs. e.g. limbs of bat and human.
3. organs with different origin but same function- analogous organs.e. g. Wings of butterfly and birds.
4. appendix is non functional part in human body.

A) Knightia is an extinct fish.

B) archaeopteryx is a link between reptiles and birds.

C) pisum sativum is botanical name of garden pea.

D) Duck billed Platypus is a link between mammals and reptiles.

• Darwin's Theory of Evolution by Natural Selection. More individuals are produced each generation that can survive. Phenotypic variation exists among individuals and the variation is heritable. Those individuals with heritable traits better suited to the environment will survive.
• Father of Genetics. Gregor Mendel, through his work on pea plants, discovered the fundamental laws of inheritance. He deduced that genes come in pairs and are inherited as distinct units, one from each parent.
• Danish botanist Wilhelm Johanssen coins the word 'gene' for the unit associated with an inherited trait.
• The Boveri–Sutton chromosome theory (also known as the chromosome theory of inheritance or the Sutton–Boveri theory) is a fundamental unifying theory of genetics which identifies chromosomes as the carriers of genetic material.

• Heredity is the passing on of traits from parents to their offspring, either through asexual reproduction or sexual reproduction; the offspring cells or organisms acquire the genetic information of their parents.
• Variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation).
• The branch of biological science which deals with heredity and variations is termed as Genetics. The word ‘genetics’ (a Greek word meaning to generate) was proposed by William Bateson (1902).
• In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection. The theory of evolution is based on the idea that all species' are related and gradually change over time.

• Plica semilunaris is a crescent-shaped fold of conjunctiva located at the inner canthus lateral to the caruncle. It is a vestigial structure that represents the third eyelid or nictitating membrane of lower vertebrates.
• Dinosaurs are a diverse group of reptiles of the clade Dinosauria that first appeared during the Triassic period.
• Artificial selection is a process in which man selects a particular desired traits for breeding, in order to generate new plants/ animals with improved characters. For e.g. Early farmers cultivated wild cabbage or Brassica oleracea. This wild cabbage developed into many varieties such as cabbage, broccoli, kohlrabi, cauliflower, kale, and brussels. These varieties were artificially selected because of their characteristic traits.
• Philosophie Zoologique is an 1809 book by the French naturalist Jean-Baptiste Lamarck, in which he outlines his pre-Darwinian theory of evolution now known as Lamarckism.