The Evolution of Urban Wildlife: Adapting to City Life

Cities are extreme habitats filled with opportunities and challenges for plants and animals. The growth of cities raises questions about the adaptability of species and the fate of those encountering urban environments for the first time.

In the historic town of Alvin, France, biologist Frédérique Santal studies siluros, a type of fish introduced to the Tarn River in 1983. These fish, originally from Eastern Europe, have since spread, exhibiting fascinating behaviors that are still poorly understood.

Researchers in Albi observed a peculiar interaction between siluros and pigeons. These two species, typically not found together, now coexist in cities. Pigeons, unaccustomed to aquatic predators, face new risks near water bodies where siluros hunt them.

The increased predation of pigeons by siluros in cities has led to new ecological interactions, potentially driving evolutionary changes in both species. This dynamic illustrates the concept of urban evolution, where urban environments shape genetic adaptations in wildlife.

Urban evolution, characterized by genetic changes in wild species within cities, reflects the profound impact of human urbanization on natural ecosystems. The city, with its concrete and steel structures, presents a unique and extreme environment influencing the survival and adaptation of wildlife.

The rapid urbanization trend, with more people living in cities than rural areas since 2017, raises questions about the influence of cities on the evolution of new species. Urban environments exert selective pressures on wildlife, driving adaptations and potentially leading to the emergence of novel species.

In Amsterdam, biologist -7 house él conducts urban nature studies, focusing on insect diversity in city parks. The urban landscape, with its increasing green spaces, supports a greater variety of insects and plants compared to intensively farmed rural areas.

Biodiversity is decreasing in both cities and the countryside, with a significant decline in insect populations. Studies show reductions of 60-80% in some areas, even in natural reserves. The scientist Florian Alterman in the Swiss Alps near Zurich has observed a drastic decrease in insect biomass, particularly moths, due to light pollution.

Florian Alterman's research focuses on the impact of light pollution on moths, particularly the spider moth. Light pollution disrupts their natural behavior, affecting their reproduction cycles and survival. Scientists are concerned about an 'insect apocalypse' due to the significant declines observed in insect populations.

Florian Alterman's experiment revealed a hereditary adaptation of moths to urban environments. This adaptation shows that some moths from urban areas are less attracted to light compared to those from rural areas, indicating a genetic change in response to city living.

Researchers in Amsterdam are observing evolutionary changes in urban wildlife, leading to potential new species specialized in city living. Organisms in cities undergo rapid evolutionary changes in behavior and physiology to thrive in urban environments, showcasing the adaptability of nature to urban settings.

Biologist Jason Mansi studies how rodents adapt to urban environments, focusing on New York City's Central Park. European immigrants brought rats to the city, leading to genetic changes in urban rodent populations. Urban wildlife faces challenges and undergoes genetic adaptations to survive in metropolitan areas.

As a tropical biologist, the speaker started their academic career in New York and decided to conduct research in Central Park after discovering genetically distinct small mammals living there. The park, opened in 1873, still houses species that existed before the city was built. Setting traps in the north end of the park to catch white-footed mice, the speaker drew inspiration from the city's subway map, viewing the parks as islands in a sea of urbanization.

The speaker highlights how white-footed mice in New York City's parks are effectively isolated due to their inability to cross streets, limiting gene spread. This isolation creates mini-galápagos within the parks, potentially driving evolution in species residing there. Investigating if these mice evolve differently in various parks, the speaker aims to understand urban wildlife adaptation.

White-footed mice prefer living in tree trunks to avoid exposure. The speaker notes the challenge of finding suitable trap locations in urban forests like Central Park. Planning to compare urban and less urbanized forest populations, the speaker seeks to capture mice in both settings to study genetic differences.

Researchers like Jason Mans and South investigate genetic differences between city and countryside animals, exploring the genetic signature of urban life. Understanding the impact of human activities on wildlife, such as waste disposal and habitat fragmentation, is crucial for comprehending urban ecology.

In Southern France, biologist Pierre-Olivier Septo studies the adaptation of yellow flowered plants in urban settings. Focusing on a plant species with two types of seeds, light ones for dispersal and heavy ones for dropping, Septo examines how urbanization affects seed characteristics. By comparing seed traits in urban and rural areas, he aims to unravel the plant's adaptation process.

While on vacation, a researcher noticed flowers growing in the city of Montpellier, sparking the idea to study flower adaptation to urban environments. This serendipitous observation led to the realization that certain plants were thriving in urban settings, contrary to their natural habitat.

Cities, particularly in Europe, are dominated by concrete, which severely fragments plant habitats. Plants in urban environments often survive in small biotopes, with their habitat limited to just one square meter. This fragmentation significantly impacts plant reproductive characteristics.

Fragmentation in cities alters the reproductive traits of plant species. Plants producing heavier seeds thrive better in urban settings as these seeds do not disperse easily over asphalt. Urban areas witness a 15% increase in plants producing heavier seeds, showcasing rapid adaptation within approximately 15 years.

Darwin would be astonished by the swift genetic changes observed in urban plant species. The extreme habitat fragmentation in cities has led to genetic adaptations occurring at a remarkable pace, contrary to the previously held belief that such changes were slow or impossible to witness directly.

Environmental toxins like PCBs and dioxins can significantly disrupt animal metabolism. New Bedford Harbor, once the most contaminated river port in the US during the 1970s, prompted the EPA to investigate the effects of pollution on fish.

A biologist and her team studied how fish adapt to pollution in New Bedford Harbor. By comparing fish populations in contaminated waters with those in uncontaminated areas, they aimed to understand the mechanisms enabling certain fish to survive in toxic environments.

The Atlantic killifish, found along the North American Atlantic coast, has been a favorite subject in biology for centuries. These fish, which do not migrate, reflect their local environment and each population is genetically unique, making them ideal for research. Scientists aim to decipher the mechanism that allows these fish to survive in extremely toxic environments by observing egg development to understand when environmental toxins affect them.

Researchers are studying the development of embryos of Atlantic killifish to identify potential effects of PCBs on heart development, circulatory system development, and size. These fish can withstand deadly environmental toxins, prompting investigation into the factors enabling certain species to adapt to urban environments.

Cities serve as unplanned large-scale experiments, and biologist Mark Johnson at the University of Toronto Mississauga is studying how organisms adapt to urban environments. Using white clover as an example, researchers worldwide, led by evolutionary biologist Estefan Gryner, are collecting white clover samples in cities like Berlin to understand if organisms adapt similarly to global urban changes.

Over 250 collaborators in 168 cities are part of a massive evolutionary biology project studying urban adaptation. This collaboration is the largest of its kind to date, aiming to understand if white clover is evolving into a global urban species. Researchers hope to find answers to evolutionary questions through this extensive study.

Geneticist Jason Mansingh at an institute near New York City captures mice to compare their genetics with those from city parks. By analyzing over 20,000 genes, researchers aim to identify traits that change in mice adapting to urban life. The study reveals significant genetic differences in mice from various parks, showcasing the impact of urban environments on wildlife.

Jason Mans and his team have captured over 100 mice, analyzing their genes to understand how urban and rural populations differ. The scientists handle the mice delicately, taking tissue samples from the ear for genetic analysis. The analysis reveals how mice in Central Park have adapted to a diet rich in human food waste, leading to significant genetic changes related to metabolism.

Researchers compare mouse populations from different areas in New York City, noting significant genetic variations. Mice from Central Park show distinct genetic changes, particularly in genes related to digestion, possibly due to their diet rich in human food waste. These genetic adaptations raise broader questions about human impact on wildlife evolution and habitat modification.

Narran Guns & Day Anna's team studies the impact of PCB toxicity on fish embryos. Exposure to PCB in Skorton Creek and New Bedford Harbor results in drastic developmental abnormalities, with lethal effects on heart function. Biochemical analysis reveals enzyme activity in fish embryos, indicating attempts to detoxify the toxin before succumbing to its effects.

The fish embryos in New Bedford appear to be well-developed and on the verge of hatching, with some already hatched. Despite being exposed to dangerous environmental toxins, the embryos show no signs of harm due to a defective enzymatic system that has evolved to resist the toxins.

Researchers in New Bedford are investigating the genetic changes responsible for the fish's resistance to toxins. Geneticist Mark from the Watson Institute is using the CRISPR-Cas method to modify fish genes effectively, aiming to identify the specific genetic sequences that confer resistance to environmental toxins.

Mark and his colleague Neil are employing modern genetic manipulation techniques to study the function of a gene related to resistance to toxins in fish embryos. Despite controversy, they believe genetic manipulation is crucial to unraveling the mystery of animals' extraordinary adaptation to deadly toxins.

Scientists hope to transfer the knowledge gained from studying fish resistance to toxins to other fish and vertebrates. Understanding the toxicology of environmental toxins can help predict which species are more vulnerable, aiding in conservation efforts and ecosystem management.

At the Max Planck Institute in Potsdam, researchers are analyzing clover samples to measure cyanide content. Clover plants producing cyanide are better protected against predators but less tolerant to cold. The qualitative test aims to identify specific genes responsible for cyanide production in clover plants.

Stefan and his team send clover samples to Toronto for further analysis by evolutionary researcher Mark Johnson. This collaborative effort aims to understand the genetic mechanisms behind cyanide production in clover plants and its implications for plant defense strategies.

The team is preparing clover for gene sequencing to determine its adaptation to urban environments. Data from Berlin shows high cyanide levels, indicating adaptation. Berlin is a city where white clover adapts well to urban and rural conditions.

Clover in central Berlin has higher cyanide levels than in rural areas, suggesting parallel evolution. The team aims to identify the environmental factors triggering this adaptation.

White clover globally adapts to urban environments due to city heat, producing more cyanide for protection. Plants and animals worldwide must adapt to city heat islands, where temperatures can be significantly higher in urban centers.

Urban heat islands influence snail evolution, affecting shell color and internal temperature. Snails of different colors may survive or perish based on heat tolerance, as seen in Amsterdam during a heatwave.

Researchers study if heat changes snails' colors and frequencies. Data collection involves scanning snail shells to analyze color variations and survival rates.

Citizen enthusiasts assist in collecting snails for evolutionary studies. An app scans and adds snail shell data to the research database, aiding in understanding adaptation to urban environments.

Urbanization and climate change threaten all animal and plant species, including monarch butterflies. Monarchs travel up to 5,000 kilometers to Mexican forests for winter, facing dangers from urbanization and climate change.

The population of monarch butterflies in the USA has decreased by 80%. In industrial areas like Toronto, endangered butterflies rest before continuing their journey and reproducing.

Monarch butterflies lay eggs on milkweed plants, which are the exclusive food source for their caterpillars. Urban areas face a decline in milkweed growth, impacting the butterfly population.

Urban areas pose challenges for monarch butterflies as they struggle to find suitable habitats due to limited milkweed growth. The design of future cities will play a crucial role in preserving biodiversity, essential for food and air quality.

Urban evolution can lead to the creation of green cities that support diverse species. By allowing some species to adapt to urban environments, pressure on other habitats can be reduced, benefiting overall biodiversity and potentially human survival.