How does non-human life in an urban ecosystem differ from non-human life in an undeveloped forest ecosystem? (Site 1)

- Urban ecosystem: highly disturbed systems. Air, water and soil pollution by various pollutants.  

- Undeveloped forest ecosystem: non disturbed systems. Low or null levels of pollution.

Explanation:

An urban ecosystem can be defined as the community of plants, animals, and humans inhabiting an urban environment. Urban ecosystems are composed of human-built physical structures (e.g., buildings, roads, sewers, railways) and green patches (e.g., parks, greenways, urban streams). In general, urban ecosystems are highly disturbed and contain high levels of pollution. In urban areas, plant life is generally overrepresented by non-native and invasive species. Moreover, animal life primarily consists of pets (e.g., dogs, cats, ornamental birds, ornamental fish) and natural species adapted to human activities, which mainly include small animals (e.g., insects). Moreover, a forest ecosystem is defined as a natural woodland unit composed of 1-biotic factors such as plants (e.g., trees) animals (e.g., insects, birds) and micro-organisms, and 2-abiotic factors (e.g., water, oxygen, carbon, nitrogen, sulfur, etc). Forest ecosystems contain low or null levels of pollutants in the air, soil and water. Forest environments represent self-regulating systems that have not been altered or manipulated by human exploitation. In consequence, in forest ecosystems, non-human life is appropriately represented by native flora and fauna.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.

the endomembrane system i think