Answer:
There are several environmental factors that causes changes in the ecosystem and the population of that area such as invasive species, extreme weather, land use change, pollution and disease.
Lets take invasive species as environmental factor. Introduction of invasive species can cause a huge change in the ecosystem and affects the native population in that area. it increases the competition for food resources and decreases the survival rate of their preys.
For example: Water hyacinth (Eichhornia crassipes). It is an invasive plant species that has very bad impact of native population as well as other population, like it reduces biological diversity, oxygen loss, decreased phytoplankton productivity, eliminate plants that animals use for nesting, and alter animal communities by blocking access to the water.
Thus invasive population can affect population by reducing biodiversity, water shortages, decreasing availability and quality of key natural resources, disturb the food chain and can cause natural calamities.
Invasive species affect the resources that native species are using and that decreases the carrying capacity of the native population as it disturbs the whole food chain.
The answer is pilus. This structure joins two bacteria of same species and allow exchange of genetic material in a process called horizontal gene transfer (conjugation). The plasmid of one of the bacteria (the mobile plasmid) is nicked once and the strand moves through the pillus to the other bacteria. It combines with the other plasmid or chromosome to for recombinant dna.
Sidney W. Fox produced proteinoid spheres, which suggest a possible route from chemical to cellular life.
Environmental Threats have come upon Madagascar lately like, Deforestation and habitat destruction. Agricultural fires. Erosion and soil degradation. Overexploitation of living resources including hunting and over-collection of species from the wild. Its a very sad thing :(