Free oxygen (O2)

The Atmosphere of the Early Earth

The atmosphere of the early earth lacked free oxygen, making it difficult for organic molecules like amino acids and carbohydrates that are essential for life processes to form. These molecules are unstable in the presence of free oxygen or any other oxidizing agent, thus they would have been destroyed as quickly as they could have been created. The lack of free oxygen created an environment that was conducive to biological processes required for the synthesis of significant organic compounds. According to most theorists, the presence of high energy ultraviolet radiation facilitated the process of photolytic decomposition of water to yield oxygen and hydrogen. Currently, the photosynthetic process serves as the major source of oxygen used for respiration.

The Domain Archaea

2. What are 3 important characteristics of the members of the domain Archaea? What is another name for this group?

The major feature characterizing the members of Archaea include the presence of cell walls. This group of organisms has fatty acids with ether bonds connecting fatty acids to glycerol molecules, unlike the eukaryotes and bacteria that use ester bonds. Besides, the members of this group adopt various types of metabolism such as denitrification, nitrogen fixation, hyperthermophilic, and chemolithotrophy. Archaea is also known as archaebacteria.

Habitat of Psychrophiles and Cryoprotectants

3. Describe the habitat of psychrophiles and why they possess cryoprotectants?

Psychrophiles are adapted to grow in a variety of habitats that possess moderate and low temperatures. They can grow in natural sources (Lake Water, river water, soil among others), marine environment, vegetables, and Polar Regions. Because these organisms can live in habitats with extremely low temperatures, they possess cryoprotectant chemicals that lower the melting point of water. Hence, it acts as antifreeze substances that maintain the optimal biological processes in this organism at low temperatures.

Evidence of Life Evolution in Oceans

4. What is the evidence that life evolved in the oceans? Where specifically does it seem likely to you life first evolved? Why?

Most scholars believe that life began in the oceans because the conditions on the primitive earth’s surface were not favorable for life to emerge. I believe the oceans are the most likely starting point of life on earth since it possessed optimal temperatures that could sustain life.

True Marine Fungi

5. Are there true marine fungi? Why or why not?

Obligate marine fungi are the true marine fungi that usually grow exclusively in the marine environment either sporadically or wholly submerged in water. Therefore, this group of fungi, unlike the facultative marine fungi that possess an ability to grow in the freshwater or terrestrial environment, represents true marine fungi.

Plankton Nets and Their Ability to Sample Plankton

6. Why are plankton nets designed the way they are? What does the weave have to do with their ability to sample plankton?

Plankton nets are designed to possess a towing line connected to bridles, a net made of nylon mesh, and code at the bottom end. The net is designed this way to enable both horizontal and vertical sampling. Besides, the weave used in the net enables researchers to analyze samples of plankton from the water environment both quantitatively and qualitatively.

The Polychaetes’ Unique Characteristics and Differences

7. What is a polychaete? What is the difference between an errant and a sedentary one? Describe one of these polychaete characteristics: epitoke, sabellid versus serpulid, castings.

The Polychaetes, which are also referred to as bristle worms, are a paraphyletic class of worms that live in the marine environment. Their bodies are made up of segments that possess a pair of fleshy protrusions known as parapodia bearing several bristles made of chitin. Errant Polychaetes are active swimmers and tend to possess well-developed jaws and sense organs and differ from sedentary ones that are considered tube dwellers or burrowers. Epitoky is a unique feature in this group of organisms that entails a process where some sexually immature species are transformed into sexually mature worms.

Benthic Marine Community

8. What is a “benthic” marine community? How is it different from other Environmental zones?

The benthic marine community is a group of organisms that are found at the bottom of the ocean. These organisms are referred to as benthos and live on the ocean floor. They include organisms such as lobsters, clams, sponges, worms, crabs, and other tiny organisms living in sediments in the oceans. Unlike any other environmental zones, benthic organisms living on the ocean floor do not depend on direct sunlight. Their source of energy is obtained from feeding on bodies of organisms that have died on the upper surface of the sea.

Planktonic Larvae and Diatom Reproduction

9. Why is it common for marine invertebrates to have planktonic larvae? How is diatom reproduction unique for planktonic organisms?

The marine invertebrates have planktonic larvae as part of their development stage because it possesses the best adaptive features that reduce predation, which is the major threat to marine invertebrates. Diatom reproduction is unique for planktonic organisms because it represents sexual reproduction that helps planktons to reproduce while maintaining its cell size.

Effect of Temperature, Salinity, and Hydrostatic Pressure on Organisms

10. How do temperature, salinity, and hydrostatic pressure affect organisms?

Organisms are affected by a change in temperature. Temperature ought to be within the optimal level for normal functioning of biological processes in the bodies of organisms. A low or high temperature outside the optimal range negatively affects the metabolic process of organisms. Salinity affects the water movement among the organisms when the salinity level in the cells of organisms is too high; water is absorbed into the cell tissues. However, if the salinity level outside the cells is too high, water may flow outside causing dehydration. Hydrostatic pressure may affect the metabolic reactions of organisms. Organisms that are not adapted to live in the oceans may succumb to high water pressure.