Pectinate muscles are parallel ridges in the walls of the atria of the heart. The name is due to their resemblance to the teeth of a comb (pecten). The heart is the organ pumps blood to all parts of the body. It is made up of four chambers, that is, right and left ventricles, left and right atria, and the blood vessels, Pulmonary artery, pulmonary vein, aorta, and venacava. An auricles are pouch like structure that increase the total filling capacity of the atrium and also increase the volume of blood that an atrium is able to contain.

3 0

3 years ago

Staphylococcus aureus is grown in heart-infusion broth at 37°C. If you start exponential phase with 100 cells, and after 90 minu

Nikolay [14]

Answer:

30 minutes

Explanation:

Bacteria reproduce by binary fission, a process by which one parent cell divides to form 2 progeny cells. Because one cell produces 2 progeny cells, bacteria are said to undergo exponential ( logarithmic) growth.

As in the case of staphylococcus aureus, we start with 100 cells , and after 90 minutes number becomes 800 that means , firstly the cells doubled (100 x 2 = 200 ) after 30 minutes. Again after 30 minutes they doubled ( 200 x 2 =400 ) and again after 30 minutes they doubled (400 x 2 = 800). So in 90 minutes 100 cells became 800 cells.

Hence the generation time for S.aureus is 30 minutes.

8 0

2 years ago

Please help due today!!<br> Brainliest given !!

Misha Larkins [42]

Answer:

The theory of evolution first formulated in Darwin's book is the process by which organisms change over time as a result of changes in heritable physical or behavioral traits that allow them to better adapt to its environment, survive and have more offspring.

Ernst Mayr divided Darwin's theory into 5 unique parts.

Ernst Mayr divided Darwin's theory into 5 unique parts.Evolution as such

Along with Buffon and Lamarck, Darwin supported the ability of species to change over time.

Common Descent

Darwin felt that all of the diversity of life on earth emerged out of the evolution from one or a few common ancestors.

Gradualism

While Lamarck felt that species-wide change could take place within the span of a few generations, Darwin felt evolution was a much slower process, taking place in innumerable small steps.

Population Speciation

This portion of Darwin's theory states that within a population, change in a species occurs as the balance of hereditary characteristics shifts across that population. This differs from Lamarck's idea that each individual in the population must undergo the same change. According to Lamarck, all giraffes living under tall trees would develop long necks. According to Darwin, some would randomly be born with long necks, this hereditary trait would gradually spread throughout the population.

Natural selection

Natural selection is often called the most unique part of Darwin's theory. Competition had been thought of as a reason that a given species might succeed or go extinct, but Darwin extended the understanding to change within a species. To continue the example of giraffes: when a giraffe is born with a longer neck than its fellows, it gains an advantage because it is able to reach more food. The long-neck giraffe is therefore stronger, lives longer, and more likely to have offspring. These offspring are born with the same long neck as their parent, though some might have even longer necks.

Returning to the example in the figure, in the first generation the application of the pesticide causes the death of most of the non-resistant insects: only those resistant to the pesticide survive. These insects reproduce and maintain their resistence so that the second generation will be more resistant than the first. So we have Natural selection, speciation, gradualism and evolution in act all together.

5 0

3 years ago