Chapter #16:
Question 1.
Insect-eating birds will decrease in number since their source of food has been reduced. The birds may also migrate to warmer areas during this period.
Question 2.
The habitat is the specific place where the organism lives e.g. a fish’s habitat is water. On the other hand, niche is the position and the role played by the organism in an ecosystem. It includes how the organism obtain food and shelter, the mode of survival, and the mode of reproduction (Sutton & Anderson, 2009, p. 46). For instance, a lion’s niche in the ecosystem is that of a predator.Question 3.
Combat: hyenas fighting for flesh
Noncombat: shading of a plant by another
Question 4.
Pelagic ecosystem producers are planktonic and are majorly made up of diatoms and photosynthetic bacteria. On the other hand, benthic ecosystem producers found near the shore are sessile algae (brown, red, or green ones). However, deep benthic ecosystems do not have producers because of the absence of light.
Question 5.
Similarity: Parasites, commensals, and mutualistic organisms live closer to other organisms and obtain some benefits from these organisms.
Difference: Unlike parasites which harm their host, commensals have no effect on their partner. On the other hand, mutualistic organisms assist each other.
Question 6.
The term phytoplankton is used to describe a group of are microscopic aquatic organisms that make their own food by the process of photosynthesis while Zooplanktons are small animals that obtain phytoplankton from aquatic ecosystems as food.
Question 7.
Primary succession is community change occurring on a new habitat which was not colonized before. On the other hand, secondary succession is community changes occurring on the previously colonized ecosystem. It begins with the destruction of the existing habitat.
Another difference between the two is that primary succession takes a long time because it takes a long time to form new soil while secondary occurs at a faster rate because the soil is already there.
Question 8.
In successional communities, some organisms disappear and get replaced by new ones. However, climax communities are stable and have little change in the composition of organisms over a long period of time.
Question 9.
DDT and PCBs are persistent toxic materials i.e. they are not broken down in the bodies of living organisms. Because of this, they accumulate in the bodies of living organisms over time. Organisms at higher trophic levels eat those at lower levels (which have already accumulated these chemicals) and thus receive the highest quantities of DDT and PCBs.
Question 10.
If farmland is left untilled, the first stage involves the growth of annual weeds. After some time, there is the establishment of perennial grasses and broadleaf plants. Eventually, a forest develops.
Chapter #19:
Question 1.
Spontaneous generation is a theory that explains that living organisms arise from non-living things (Hogg, 2013). For instance, it was believed that mice arise from corn and maggots from rotting meat. Experiments by Redi and Needham have, however, disproved this hypothesis.
Question 2.
Biogenesis is a term attributed to Louis Pasteur that explains that all living organisms arise from other living things and can never be spontaneously generated.
Question 3.
Coacervates is a model that explains that a group of organic molecules could have been surrounded by a film of water (Concepts in Biology’ 2007 Ed.2007 Edition, n.d., p. 409). Another model, proteinoid microspheres, explains that organic molecules were separated from others with a protein covering.
Question 4.
This is because evidence shows that the early earth was devoid of oxygen in its atmosphere (Nelson & Cox, 2013, p. 35).
Question 5.
Organelles such as mitochondria and chloroplasts possess their own deoxyribonucleic acid, ribosomes, and membranes. The deoxyribonucleic acid and ribosomes resemble bacteria.
Question 6.
Redi— showed that for maggots to develop, flies must have access to rotting meat
Needham— to show that living things exist, he put boiled mutton in stoppered flasks. After some few days, he reported the presence of life which he believed arose from non-life.
Spallanzani— he came up with an experiment that showed that if the broth was boiled and not exposed to air, living organisms do not grow on it.
Pasteur—using a swan-neck flask, he proved that oxygen alone could not cause spontaneous generation.
Question 7.
Reducing atmosphere > First organic molecule > living cell > respiration (anaerobic) > photosynthesis > oxidizing atmosphere
Question 8.
The process of aerobic respiration could evolve. Also, the ozone layer could have developed and decreased the amount of UV rays of light reaching the earth and leading to mutations.
Chapter #20:
Question 1.
The current naming system, the binomial nomenclature system, was developed by Carolus Linnaeus (‘Binomial nomenclature’, n.d.). This system replaced one in which living things were being described using many words.
Question 2.
Protista— organisms in the kingdom are single-celled (having one cell) or colonial (having a group of cells). They lack advanced organ systems.
Fungi— organisms in this kingdom are heterotrophic and contain cell walls made of with cell chitin.
Plantae— organisms in this kingdom are capable of undergoing photosynthesis. Their organ systems are complex.
Animalia— organisms in this kingdom are heterotrophic and show movement.
Question 3.
Question 4.
Viruses are not capable of reproducing on their own and, therefore, they must get to living cells of other organisms and use the cells machinery to produce copies of itself.
Question 5.
Unlike common names which differ from one society to another, scientific names are the same worldwide. Second, in the development of scientific names, evolutionary relationships are adhered to. This is not the case in common names. Lastly, scientific names consist of two names (the generic and the specific name). Common names do not have this (‘Scientific and common names’, n.d.)
Question 6.
The deoxyribonucleic acid (DNA) of eubacteria is made of DNA loop which lacks introns. On the other hand, the DNA of archaea has introns. Second, unlike eubacteria, archaea inhabit extreme environments. Moreover, their cells walls are composed of different materials.
Question 7.
Viruses are made of nucleic acids (either deoxyribonucleic acid or ribonucleic acid) which are enclosed by a protein. On the other hand, viroids have naked pieces of ribonucleic acid.
Chapter #24:
Question 1.
The lymphatic systems refer to a network of tubes permeating the whole body. It helps in draining of fluids (lymph) from the tissues and drains this fluid back to the bloodstream. Lymph are fluids that pass through the thin walls of capillaries into the tissues and do not flow back to the vascular system. The major roles of the lymphatic system are: regulating the body’s fluid levels, filtration of bacteria, and a site for fighting infections as it houses the white blood cells (Ehrlich & Schroeder, 2012, p. 171).
Question 2.
The red blood cells (RBCs) contain a pigment known as haemoglobin. Haemoglobin has a high affinity for oxygen and thus, combines with oxygen forming an unstable compound known as oxyhaemoglobin. Oxygen is transported in the form of oxyhaemoglobin (Huat, 2012).
The RBCs are also involved in the transportation of carbon (IV) oxide. In this process, carbon (IV) oxide diffuses into the RBCs in the blood capillaries and combines with water in the blood forming a weak carbonic acid (H2CO3) — a form in which carbon (IV) oxide is transported in the blood. This reaction is catalyzed by carbonic anhydrase enzymes found in the RBCs (Beebe & Myers, 2012)
Question 3.
Heart—pumps blood to various parts of the body
Arteries—carry blood away from the heart
Veins— carry blood to the heart
Arterioles— transport blood from arteries to tissues and also involved in regulating blood going to certain parts of the body.
Blood— transport and distributes various substances e.g. gases, heat, and hormones.
Capillaries—allow the exchange of substances between blood and cells surrounding the capillaries.
Question 4.
Inhalation and exhalation occur as a result of pressure differences in the thorax and the external environment. During inhalation process, the intercostal muscles and diaphragm contract. This is followed by the flattening of the diaphragm and movement of the rib cage upwards and outwards. These changes lead to the expansion of the thoracic cavity. As a result, the pressure of the thoracic cavity decreases. This makes external air rush from the outside (whose pressure is higher than that of the thoracic cavity) to the lungs leading to equalization of the pressures (Singh & Kaur, n.d., p. 42)
During the process of exhalation, the diaphragm and intercostal muscles relax. This makes both to return to their resting positions. Because of this, the thoracic cavity reduces in size, thereby making its pressure to increase. This change in pressure forces air out of the lungs.
Question 5.
The spleen: It screens for infections and also involved in filtering damaged red blood cells.
The thymus: manufactures the leucocytes (white blood cells) that fight the pathogens.
Tonsils: this is a lymph node found at the back of the throat. They are the first organ to fight infections because of the pathogens that pass through the mouth.
Lymph nodes: are where leucocytes screen the lymph for foreign substances.
Question 6.
The food particles are dissolved and reduced in size e.g. by mastication process and by enzymatic actions.
The surface area of the small intestine is increased so as to maximise digestion as well as absorption.
A close contact is established between the surface area of the alimentary canal and both the circulatory and lymphatic system.
Question 7.
It is involved in the production of bile needed for emulsification of fats.
It is involved in filtration of foreign materials from the blood.
It makes toxic materials less toxic, a process which is known as detoxification.
Chapter #24:
Question 1.
Positive feedback is not involved in maintaining homeostasis as its actions move the body away from the normal or set conditions thus endangering life. For instance, if the body temperature was rising, positive feedback will lead to a further rise in temperature thus affecting body’s physiological activities.
Question 2.
Differences between peripheral nervous system (PNS) and the central nervous system (CNS:
In the CNS, a group of neurons is known as nuclei while in the PNS, they are called ganglia.
Also, a group of axons in the CNS are called tracts. In the PNS, they are called nerves (‘Neuroscience For Kids - Explore the nervous system,' n.d.)
Differences between sensory and motor nerves:
Sensory nerves have long dendrites and short axons while motor nerves have short dendrites and long axons.
Sensory nerves have their cell bodies and dendrites outside the spinal cord with the cell body present in dorsal root ganglion. Motor nerves, on the other hand, have dendrites and cell bodies in the spinal cord with the axon outside the spinal cord.
Sensory nerves carry impulses to the spinal cord while motor nerves carry impulses to effectors.
Question 3.
Skeletal muscle undergoes rapid contraction, does not stay contracted, and get its stimulation from the nervous system.
Smooth muscle undergoes contraction slowly, is capable of staying contracted, and derive its stimulation from within itself.
Cardiac muscle undergoes rapid contraction, does not stay contracted, and derive its stimulation from within itself.
Question 4.
Actin and myosin are
Actin and myosin bind to each other and also slide past each other. This type of binding is reversible.
ATP supplies energy for contraction of muscles
Troponin and tropomyosin shield actin from getting bonded to myosin. However, the upon the release of calcium ions,
Question 5.
In antagonistic pair of muscles, one muscle moves a joint while another one returns it to its original resting position. In the absence of antagonistic pairing of muscles, the joint would not be returned to its original position.
Question 6.
Timing and rate of growth of tissues are determined by the time of production of growth or sex hormones and the quantities of these hormones.
Question 7.
Free Nerve Endings
Tactile Corpuscles
Lamellated Corpuscles
References
Beebe, R., & Myers, J. (2012). Professional Paramedic, Volume I: Foundations of Paramedic Care. Cengage Learning.
Binomial nomenclature. (n.d.). Retrieved 18 April 2016, from http://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/b/Binomial_nomenclature.htm
Concepts in Biology’ 2007 Ed.2007 Edition. (n.d.). Rex Bookstore, Inc.
Ehrlich, A., & Schroeder, C. L. (2012). Medical Terminology for Health Professions. Cengage Learning.
Hogg, S. (2013). Essential Microbiology. John Wiley & Sons.
Huat, S. C. T., A. S. Ong, Lam Chang. (2012). Express Science Form 3. Pelangi ePublishing Sdn Bhd.
Nelson, D. L., & Cox, M. M. (2013). CourseSmart International E-Book for Principles of Biochemistry. Palgrave Macmillan.
Neuroscience For Kids - Explore the nervous system. (n.d.). Retrieved 19 April 2016, from https://faculty.washington.edu/chudler/nsdivide.html
Scientific and common names. (n.d.). Retrieved 18 April 2016, from http://entnemdept.ifas.ufl.edu/walker/buzz/h00names.htm
SINGH, L., & KAUR, M. (n.d.). SCIENCE & TECHNOLOGY FOR CLASS X (BIOLOGY). S. Chand Publishing.
Sutton, M. Q., & Anderson, E. N. (2009). Introduction to Cultural Ecology. Rowman Altamira.
