Hi
The term lack of genetic diversity for a particular population refers to the fact that there are less number of alleles and less range of phenotypes and traits like (height, skin, color, ability to cope disease, ability to change metabolism as per requirement etc).
If we talk about endangered species, they are the specie which are prone to be extinct in near future because their population is very less in number. There can be multiple reason of becoming endangered for a population such as over hunting etc.
So when we say that an endangered population is genetically less diverse, it means that there are further difficulties that hinder their recovery.
For example: If a calamity stucks, all organisms that are already low in number and also genetically less diverse, so they cannot cope with calamity and get extinct. However, if this population is genetically more diverse, some organisms may survive some may die, and those which survive can recover the population. That is why it becomes more difficult to recover an endangered specie if it is genetically less diverse. The more the genetic diversity, better it is for specie.
Hope it help!
Answer:
Only when a microorganism has successfully established a site of infection in the host does disease occur, and little damage will be caused unless the agent is able to spread from the original site of infection or can secrete toxins that can spread to other parts of the body. Extracellular pathogens spread by direct extension of the focus of infection through the lymphatics or the bloodstream. Usually, spread by the bloodstream occurs only after the lymphatic system has been overwhelmed by the burden of infectious agent. Obligate intracellular pathogens must spread from cell to cell; they do so either by direct transmission from one cell to the next or by release into the extracellular fluid and reinfection of both adjacent and distant cells. Many common food poisoning organisms cause pathology without spreading into the tissues. They establish a site of infection on the epithelial surface in the lumen of the gut and cause no direct pathology themselves, but they secrete toxins that cause damage either in situ or after crossing the epithelial barrier and entering the circulation.
Most infectious agents show a significant degree of host specificity, causing disease only in one or a few related species. What determines host specificity for every agent is not known, but the requirement for attachment to a particular cell-surface molecule is one critical factor. As other interactions with host cells are also commonly needed to support replication, most pathogens have a limited host range. The molecular mechanisms of host specificity comprise an area of research known as molecular pathogenesis, which falls outside the scope of this book.
While most microorganisms are repelled by innate host defenses, an initial infection, once established, generally leads to perceptible disease followed by an effective host adaptive immune response. This is initiated in the local lymphoid tissue, in response to antigens presented by dendritic cells activated during the course of the innate immune response (Fig. 10.2, third and fourth panels). Antigen-specific effector T cells and antibody-secreting B cells are generated by clonal expansion and differentiation over the course of several days, during which time the induced responses of innate immunity continue to function. Eventually, antigen-specific T cells and then antibodies are released into the blood and recruited to the site of infection (Fig. 10.2, last panel). A cure involves the clearance of extracellular infectious particles by antibodies and the clearance of intracellular residues of infection through the actions of effector T cells.
Explanation:
if wrong correct me
Answer:
Most frogs see well only at a distance, but they have excellent night vision and are very sensitive to movement.This peripheral vision helps them spot predators and prey. Humans and other mammals focus images by changing the shape of the lens. Like a camera lens, frog eyes focus by moving the lens back and forth.
Atomic number of an atom equals to the number of nucleus in the nucleus of the atom. Therefore, the answer is 74.
The proton of an element is never changed. No matter if it's an atom or ion. It's like an ID number for an element. It defines the type of element. Don't mix up atomic number with mass number though, mass number is the total sum of of the number of protons and neutrons in an atom.
Theres one more subatomic particle in an atom, that is electrons. But since they're too light, they won't be counted in mass. Also, the number of electrons in an atom equals to the number of proton, also the atomic number. If the number of electrons is different, it's no longer an atom, but an ion.
