Origin of Life: Pasteur, Darwin, Miller & Evolution Explained
Act II: The Life
Scene I: The Early Word
What role did Pasteur and Darwin play in explaining the origin of life?
Pasteur demonstrated that microscopic germs are ubiquitous. He conducted an experiment isolating meat and vegetable broth, boiling it to sterilize it, and concluded that life does not arise spontaneously but is a process that takes time.
Darwin’s principle of evolution of species posits that species are modified by natural selection, where nature selects the fittest for survival.
What did
Read MoreUnderstanding Alleles and Genetic Concepts
Alleles
Alternative alleles of a gene, located at the same locus on homologous chromosomes, are responsible for different phenotypic manifestations of a trait.
Lethal Alleles
A lethal allele causes the death of a homozygous individual who possesses it.
Recessive Alleles
A recessive allele does not express itself in a heterozygote.
Multiple Alleles
Multiple alleles occur when a gene is represented by more than two alleles.
Autofecundation (Self-Fertilization)
Autofecundation is a mode of fertilization in
Read MoreCentral and Peripheral Nervous System, Bones, Muscles, and Heart
Central Nervous System
The central nervous system and encephalopathy (brain) is divided into two hemispheres. On its central surface, protrusions are called gyri and indentations are called sulci. The outermost part is gray matter. The cerebral cortex receives information from the organs, develops orders, stores and processes the information. In the inner zone is the white matter.
- Cerebellum: Below the brain, it is divided into two hemispheres and shows a series of cerebellar circumvolutions. It
Organic Substances, Nutrients, and Digestion
Organic and Inorganic Substances
Organic substances are mostly composed of carbon and hydrogen. Inorganic substances are not exclusive to living matter.
Types of Food
- Simple foods: Consist of a single type of nutrient, such as oil.
- Compound foods: Are composed of different nutrients.
Water is the most abundant compound. Mineral salts are dissolved in all body fluids.
Organic Constituents
- Carbohydrates: Such as glucose (which tastes sweet), starch, and cellulose.
- Lipids: Fats are substances that do not dissolve
Human Reproduction: Characteristics, Organs, and Processes
Human Reproduction: Key Characteristics
Human reproduction involves several key characteristics:
- It involves two sexes with distinct anatomical differences.
- Each sex produces a specific type of sex cell, called a gamete. Men produce sperm, and women produce ova (eggs).
- Fertilization is internal. The male deposits sperm into the female’s body, where the union of the gametes occurs.
- Fertilization results in a single cell, the zygote, which develops for approximately 40 weeks inside the mother, leading
Human Body Systems: Nutrition, Digestion, and More
Food and Nutrition
Mediterranean Diet: Emphasizes oil, grains, pulses, fish, vegetables, and fruit.
Digestive, Respiratory, and Circulatory Systems
The Digestive System: Process of Food Digestion
Digestion begins in the mouth, where food is mixed with saliva, initiating the chemical process of forming the bolus. Food is compressed and directed from the mouth to the esophagus by swallowing. From the esophagus, it moves to the stomach, where it is mixed with hydrochloric acid. The bolus is transformed
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