1. Please describe the relationship between populations and species? (50 words)
According to the textbook, the biological populations are “groups of individuals of the same species that are subdivided from other populations by geography and are somewhat independent form other groups” (Belk & Maier, 2013); while a population means all of the members of species in one ecosystem, species is a certain unique type of organism in the entire biosphere.
2. Define evolution. (150 words)
For biologists, evolution represents the two different definitions – “either the process or an organizing principle, that is, a theory” (Belk & Maier, 2013, p. 222). In general, the term ‘evolution’ means change; this change can occur within biological population through generations. According to the course text, “changes that occur within a biological population are referred to as microevolution.” (Belk & Maier, 2013, p. 223) Darwin defined ‘evolution’ as a process by which organism change over time as a result of changing in their heritable physical or behavioral traits (Than, 2018). Changes within population are critical as all transformations allow organism to better adapt to different environments, climate changes, temperatures, resources, and places of living and survive and reproduce within new environment. The theory of evolution is one of the most powerful and influential in the history of science and supported by multiple scientific evidence, sources, scientific disciplines, such as genetics, biology, geology, paleontology, etc.
3. How would you refute the argument, “evolution is only a theory?” (50 words)
Scientific theories are supported by numerous lines of evidence (Belk & Maier, 2013). The theory of evolution is supported by multiple evidence from different sources and disciplines, which show that evolution is a true science, not ‘just a theory’. It is a real science as it helps researchers to solve many real issues, find real answers to real questions; evolution is a science that explains the universe in natural terms.
4. How do scientists determine if two individuals are from the same species? (75 words)
Previous fossils and general physical appearance are the major criteria to determine the species delineation. Evidence indicates that “the fossilized remains of extinct species in many groups of organisms demonstrate a progression of forms from more ancient to more modern types” (Belk & Maier, 2013, p. 247). DNA study can be effective method to determine if tow individuals are from the same species. The study about anatomical similarities is one more classic method to determine the differences and similarities between species.
5. Why is there such a large discrepancy between the number of described species on earth and the estimated number of species that actually occur here? (50 words)
Species is defined as a group of individuals that can interbreed and produce fertile offspring.” (Belk & Maier, 2013, p. 302) Because of continuous transformations, changes, and endless survive-reproduce cycle, there is a large discrepancy between the number of described species on earth and the estimated number of species that actually occur.
6. What is convergent evolution and how can convergent evolution in the past affect the description of fossilized species? (75 words)
Convergent evolution means “evolution of similar structures in unrelated organisms with similar lifestyles” (Belk & Maier, 2013, p. 232). For example, birds and bats have wings but their organisms are not related. Environmental circumstances that require similar development fro adaptation can cause convergent evolution among different species. Convergent evolution in the past can affect the description of fossilized species; all organisms have specific circumstances, transformations, and interaction with environment, which may affect the description of fossilized species.
7. Why is the fossil record incomplete? Why is it important in spite of that fact? (50 words)
Fossils provide a record of organisms left in soil or rocks that lived long time ago (Belk & Maier, 2013). They provide evidence that animals and plants can change over time but often they are incomplete: “sediment has to cover an organism’s remains in order for the long fossilization process to begin. Most organisms decompose before this happens. Fossilization odds increase if the organism happened to exist in large numbers or lived in or around sediment” (Lamb, n.d.).
8. What were your ideas about evolution prior to this unit? What are your thoughts after its completion? Prior to this unit, I consider evolution is no more than a long-lasting process of continuous changes and transformations on Earth. Many believe that Darwin’s theory is no more than a hypothesis; it si not a scientific law. But analyzing the theory of evolution, it becomes obvious that there is evidence from multiple sources and disciplines that support evolution as a true science. After studying this unit, I realize that the theory of evolution can tell us a lot of interesting concepts; it helps understand who we are, where we come from, how we evolved. The theory of evolution shows that all modern organisms are related to each other and came from one single common ancestor.
Belk, C. & Maier, V. (2013). Biology: Science for Life with Physiology, 4th ed. Benjamin Cummings.
Lamb, R. (n.d.). How incomplete is the fossil record? Retrieved from https://science.howstuffworks.com/environmental/earth/geology/incomplete-fossil-record.htm
Than, K. (2018). What is Darwin’s theory of Evolution? Retrieved from https://www.livescience.com/474-controversy-evolution-works.html