Answer:
- Invertebrates may have an <u>exoskeleton</u> for protection and support.
- Vertebrates have a backbone and a skull.
Explanation:
Invertebrates are usually small animals, they usually lack of an articulated internal skeleton, although some do, but it is an external skeleton called an exoskeleton. Many have shells, shells, or covers of some hard substance.
A vertebrate is an animal that has a skeleton with a vertebral column and a skull, and whose central nervous system is made up of the spinal cord and the brain.
<span>a. It is important that the hairs are pulled rather than cut as DNA is found in the hair follicle which is located under the scalp. This is where the hair gets it's blood supply. If there are any drugs in the person's system, traces of it will go into the hair shaft from the blood supply by the hair follicle.
b. It's necessary because hair doesn't grow constant or consistent and 25 to 50 hairs are needed for an accurate test. This decreases false positive results.
c. The hair drug test can go back to about 90 days to see if she has been clean within that time. Beyond that, interviews with family and friends would also be helpful. Phone records would also show if there has been any contact with a dealer.
d.This doesn't prove she's guilty because it just places her at the scene and could be circumstantial.</span>
Answer:
Introduction on Argentinian Red And, <em>Solenopsis invicta</em>, in the United States.
Explanation:
A species is considered to be introduced when it has been released intentionally or accidentally in a new place or area, out of its natural geographical distribution range, during historical times.
The, Argentinian Red Ant, Solenopsis invicta was introduced by accident in the United States in the 1930 year when some commercial ship coming from Brazil unloaded infested merchandise. Since that date, it has been colonizing several areas, expanding in a range of 30 to 50 kilometers per year. Nowadays it is occupying more than 110 million hectares, causing several problems:
- Biological problems: It is a very aggressive species that can <em>affect animals and plants</em>. In Texas, the <em>invertebrates' biodiversity decreased by 40% and the local ants decreased by 70%.</em> Their nests' building affects the roots of plants causing important <em>harvest losses</em>.
- Economical problems: The United States government has expended more than 250 million dollars trying to solve the problem, while the yearly losses exceed 1,000 dollars. The harvest losses have causes an important decrease in production.
- Sanitary problems: These ants might be considered dangerous as they have attacked people and animals. Texas invests 750,000 dollars a year to treat wounds in cattle and other affected animals.
There are some steps to prevent and reduce biological invasions, such as introduction prevention, eradication <em>when it is still possible</em>, contention to <em>avoid the species expansion</em>, expansion control (biological, mechanical, chemical), and restoration of the affected areas.
In the case of the Red Ant it would have been very important to control the state of the merchandise coming from Brazil to avoid the ant's introduction and its posterior spread. It also would have been important to deal harder with the problem when it was recently to avoid the ants' expansion by educating the people about invasive species and how to react about it, and by applying some eradication actions when it was possible. Nowadays the species is under control, but they can not completely eradicate it.
Population of older female elephants different from the younger female elephants is described below.
Explanation:
- THE OLDEST ELEPHANTS wandering Mozambique’s Gorongosa National Park bear the indelible markings of the civil war that gripped the country for 15 years: Many are tuskless. They’re the lone survivors of a conflict that killed about 90 percent of these beleaguered animals, slaughtered for ivory to finance weapons and for meat to feed the fighters.
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Hunting gave elephants that didn’t grow tusks a biological advantage in Gorongosa. Recent figures suggest that about a third of younger females—the generation born after the war ended in 1992—never developed tusks. Normally, tusklessness would occur only in about 2 to 4 percent of female African elephants.
- New, as yet unpublished, research she’s compiled indicates that of the 200 known adult females, 51 percent of those that survived the war—animals 25 years or older—are tuskless. And 32 percent of the female elephants born since the war are tuskless.
- A male elephant’s tusks are bigger and heavier than those of a female of the same age, says Poole, who serves as scientific director of a nonprofit called ElephantVoices. “But once there’s been heavy poaching pressure on a population, then the poachers start to focus on the older females as well,” she explains. “Over time, with the older age population, you start to get this really higher proportion of tuskless females.”
- “The prevalence of tusklessness in Addo is truly remarkable and underscores the fact that high levels of poaching pressure can do more than just remove individuals from a population,” says Ryan Long, a behavioral ecologist at the University of Idaho and a National Geographic Explorer. The “consequences of such dramatic changes in elephant populations are only just beginning to be explored.”
