Transmitted, vertical
A transparent specimen is viewed through a microscope using transmitted light while an opaque object requires vertical illumination.
Transmitted light is the light that passes through an object. Transmitted light microscopy is any kind of microscopy in which the light is transmitted from a source located directly across the specimen from the objective. The light is commonly passed through a condenser in order to focus it on the specimen to obtain very high illumination. After the light passes through the specimen, the image of the specimen moves through the objective lens and later to the oculars where the enlarged image is viewed.
Answer:
To find the extinct species and their divergence of characters can be studied using molecular genetic techniques.
Explanation:
- Paleontology is the study of ancient species and their remaining that were found millions of years ago. These species extinction can be found and manipulated to find out the origin or divergence of species from their origin
- The samples of these species may contains their remains that help the biologist to isolate and analyze their protein or DNA. when the DNA is isolated their sequences can be generated using molecular biology techniques.
- When the sequences are identified by advanced molecular biology techniques, the existence and similarities of different species due to their convergence or divergence can be identified.
- By identifying the convergence or divergence the characteristics, evolutionary change in behavior, variation in appearance can be studied.
- By using these techniques, biologist have found that <em>homo sapiens</em> are 99% have their similarities with chimpanzee
- Thus, using genetics in paleontology helps us to understand adaptation a species is changing according to the evolutionary changes.
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Pairs of Unit Factors, or Genes
Mendel proposed that paired unit factors of heredity were transmitted faithfully from generation to generation by the dissociation and reassociation of paired factors during gametogenesis and fertilization, respectively. After he crossed peas with contrasting traits and found that the recessive trait resurfaced in the F2 generation, Mendel deduced that hereditary factors must be inherited as discrete units. This finding contradicted the belief at that time that parental traits were blended in the offspring.
A gene is made up of short sections of DNA that are contained on a chromosome within the nucleus of a cell. Genes control the development and function of all organs and all working systems in the body. A gene has a certain influence on how the cell works; the same gene in many different cells determines a certain physical or biochemical feature of the whole body (e.g., eye color or reproductive functions). All human cells hold approximately 21,000 different genes.
Genetics is the science of the way traits are passed from parent to offspring. For all forms of life, continuity of the species depends upon the genetic code being passed from parent to offspring. Evolution by natural selection is dependent on traits being heritable. Genetics is very important in human physiology because all attributes of the human body are affected by a person’s genetic code. It can be as simple as eye color, height, or hair color. Or it can be as complex as how well your liver processes toxins, whether you will be prone to heart disease or breast cancer, and whether you will be color
Passive transport is a movement ofbiochemicals and other atomic or molecularsubstances across cell membranes without need of energy input. Unlike active transport, it does not require an input of cellular energy because it is instead driven by the tendency of the system to grow in entropy. The rate of passive transport depends on thepermeability of the cell membrane, which, in turn, depends on the organization and characteristics of the membrane lipids andproteins. The four main kinds of passive transport are simple diffusion, facilitated diffusion, filtration and osmosis.
