Introduction
There is a wide range of issues and a diversity of species to which biological research is devoted. Despite that, they are united by an attempt to identify the evolutionary meaning of what is happening in the world of animals and humans. This paper provides reflective summaries for two IBiology research talks concerning biological preconditions for changes in female aggressiveness and the impact of human population growth on the critical reduction of biodiversity worldwide.
Understanding Female Aggression in Fruit Flies
Research Issues and Significance
According to common beliefs and biological observations, males are considered more aggressive than females because of their reproductive strategy. In the animal world, they compete for the opportunity to mate with females, since the continuation of their genus depends on the number of mates. However, cases of aggressiveness among female populations are also observed in wildlife. For example, female hyenas are more aggressive than males and demonstrate a higher level of dominance (Bath, 2017). The evolutionary theory has no consistent description of the mechanism of appearance and functionality of female aggressiveness. Insights on this subject could also illuminate how people behave in this regard.
Nevertheless, there is a hypothesis that female aggressiveness increases after mating due to the need for female offspring to grow up and obtain food and other resources for them. Such instances of hostility for resources for offspring among females have been observed in many species, from insects to birds and mammals. The study by Bath (2017) was intended to test this hypothesis for fruit flies. The researchers divided the female flies into two groups: mating and virgin. After that, the flies spent some time without food and then were placed together in a space with protein-rich food.
Research Findings
The research revealed that mated flies tend to be aggressive for more extended periods and use such extreme forms as headbutting fighting for access to food. The main concern of the second phase of the study was to find out what exactly provokes this behaviour. Bath (2017) suggested that the ability to lay eggs would be crucial in this regard. However, it was found that mated sterile flies also exhibit a higher level of aggression than virgin ones. Surprisingly, it was discovered that this behaviour is not related to the ability to produce eggs, but to substances that are transferred from males to females during ejaculation, including sperm and sex peptides.
It should be noted that the research results can be interpreted in two ways. On the one hand, changes in female behaviour due to the influence of male ejaculation can be seen as beneficial for her and her offspring, enabling her to obtain the necessary resources more efficiently. On the other hand, it may be a form of male biological manipulation, as such aggressiveness can be dangerous to the female and even shorten her lifespan (Bath, 2017). These remarkable findings leave many questions, such as the mechanism of sperm and sex peptide impact on a female. Moreover, these results cannot be confidently transferred to other species, including humans. However, the discovered connection sheds new light on the evolutionary meaning of female aggressiveness and creates opportunities for further study.
Loss of Biodiversity in a Human-Dominated World
Biodiversity Reduction Factors
There have been many natural causes and events that have contributed to biodiversity loss, but at present, the greatest threat to it is posed by anthropogenic factors. Humans have colonized the planet for many thousands of years, starting with Africa, and by now have occupied all continents except Antarctica. The population of people has critically increased in the last century. As a result of hunting, almost all larger animals were exterminated in the first place (Hadly, 2015). In addition to direct extermination, human impacts on the Earth’s ecosystem have many indirect effects that threaten biodegradation.
This is primarily climate change which affects the living conditions of animals and the whole environment and makes them less habitable over time. Deforestation and urbanization also have devastating effects, manifested through the reduction of living space and changes in the chemical composition of the air. Hadly (2015) states that transport hubs and routes severely damage ecosystems as they interfere with the regular paths of animals. Moreover, the breeding of pets and livestock creates a critical inequality between their biomass and that of wild animals, which have a tiny proportion.
Implications and Significance
Due to dramatic changes in ecosystems, animals are forced to migrate to new, usually northern areas where they meet unknown species, and their interactions do not always lead to positive consequences. Reserves and national parks do not solve the problem because they lack connectivity to other areas, which prevents animals from moving naturally (Hadly, 2015). Cities and transport hubs also contribute to the separation of environmental systems. Ecological connectivity is one of the most important factors in increasing genetic diversity, as it allows different species to encounter and mate, creating new genotypes. At the same time, when the quantity of species decreases drastically, or they become separated from each other, this results in a reduction in the number of genotypes and bottleneck.
Reduced genetic diversity leads to more frequent expressions of recessive genes and inbreeding that lead to the appearance of less adapted species. For instance, Hadly (2015) provides an example of an entirely artificially bred white tiger that could not survive in the wild. Such shifts are occurring in the wild and, together with other factors, have resulted in the extinction of many species to date and threats of extinction for a quarter of existing species. The fundamental significance of this issue is that the loss of biodiversity can happen rapidly while its restoration requires a long period of evolution. Such large-scale alterations in the ecosystem cannot but affect humans if these trends continue.
Conclusion
It should be mentioned that these research talks touch upon different evolutionary issues and problems and come to different conclusions. Bath’s research clarifies the mechanism of female aggressiveness and can serve as a basis for explaining the same in humans. Hadly describes a paramount problem that is highly relevant to the modern environment, and the data set both explains the situation and raises particular concerns.
References
Bath, E. (2017). Understanding female aggression in fruit flies. Web.
Hadly, E. (2015). Loss of biodiversity in a human-dominated world. Web.