Velvetfish via Getty Images Lily pads, which house many species, grow on the edge of a freshwater lake in Cape Cod, Massachusetts.

Simply put, biodiversity is the huge variety of living organisms on Earth — plants and animals, insects and fungi, microbes and man. Biodiversity can be looked at on the species level, down to genes, or out to whole ecosystems and how they interact. Losing animal and plant species can have negative impacts we didn’t expect, said Kathy Halvorsen, professor of natural resource policy at Michigan Technological University. “We need all these cogs in the machine.” “We often don’t think about those interconnections,” said Dayer, who studies what people think and do related to conservation. “You can’t just study people, you can’t just study the environment. That’s not actually how the world works.” People may define the importance of biodiversity in different ways. Some believe in the intrinsic value of biodiversity — who wants to live in a world without blue whales and butterflies? Others focus on utilitarian aspects: We enjoy outdoor recreation, depend on agriculture and derive physical and mental health benefits from nature. Many may not feel deeply connected to nature themselves, but want to leave the Earth’s legacy intact for their children. “[Biodiversity] is vital to our well-being, our ability to feed ourselves, our ability to have clean water, clean air. We should care because it helps people,” Halvorsen said. “We should also care because caring makes us more human and more humane. There are other beings on Earth, and caring about wanting to protect them is something we have an ethical obligation to do.” Here are just some of the ways that biodiversity impacts our lives, every single day. The food we eat

maexico via Getty Images A bee pollinating an almond tree.

Like coffee and chocolate? Do you eat fruits and berries? Then you’ve benefited from the work of more than 20,000 species of pollinators, including wasps, bees, flies, beetles, butterflies, birds and even bats, lemurs and lizards. At least 85% of the world’s leading crops depend in some way on pollinating animals. “Without them, we would be missing a lot of our really important food sources,” said Halvorsen. California produces more than 80% of the world’s almonds, a feat that requires pollination by virtually every commercial beehive in the U.S., which are shipped in from around the country every February. But bee colonies have been declining by 30% a year on average, due to a combination of climate change, loss of wildflower species, pesticides and other stressors. As University of California, Davis pollination expert Christine Casey put it: no bees, no almonds. Researchers fear that declines in insect pollinators globally will dampen agricultural productivity, increasing the need for land and leading to more habitat destruction.

We can’t save ecosystems when they’re desperately sick. Donald Waller, University of Wisconsin, Madison

Seafood is the main source of animal protein for about a billion people worldwide. But overfishing, along with climate change, is hitting fish populations hard. And fish farming can’t make up the difference. In some ways, it can exacerbate an already bad situation. It takes an enormous amount of fossil fuel energy to produce food for fisheries, which is costly and ecologically damaging. And fish farms contribute to water pollution. A smarter response? Rein in overfishing so that marine ecosystems can balance species diversity the natural way. And it takes biodiversity to support the biodiversity that supports our food supply. Consider the wildflowers: bees and butterflies need native vegetation to survive. Native fungi could control the spread of invasive insects that are ravaging apple and grape orchards. Bats are “voracious predators” of many crop-eating pests, according to a 2011 study in the journal Science that estimated the decline of bat populations in North America could lead to agricultural losses of more than $3.7 billion a year. The air we breathe and the water we drink

bluejayphoto via Getty Images Giant sequoia trees, also known as giant redwoods, in Sequoia National Park, California.

Plants’ ability to capture and store carbon dioxide from the atmosphere is a crucial piece of our continued survival. The fastest, cheapest, most efficient way to bring down greenhouse gases and mitigate some of the effects of climate change is to grow more trees around the world and preserve the ones we have, said Donald Waller, a botany and environmental studies professor at the University of Wisconsin, Madison. “We could essentially be absorbing more carbon than generated by all the cars and trucks on our highways.” Trees — especially in the middle of bustling cities — can pull pollutants out of the air and lower air temperature. But making the world green is not enough, he added; we need to make sure there is a diversity in our plant life. Forests are seeing “radical, pervasive change,” according to Waller. As native species die off and diversity in forests dwindles, plant life loses its resilience. A simplified forest that is home to just a few species is going to be much more vulnerable to drought, flood, fire or invasive species. “If you’re down to a forest of five or six [species] and you lose three, you’re in real trouble. We need to protect plant diversity and forest diversity on the front end. We can’t save ecosystems when they’re desperately sick.”

Michael Warren via Getty Images An algae bloom in the Colorado River above the Grand Canyon.

When it comes to naturally combating water pollution, research suggests that ecosystems that support more species do a better job of removing harmful pollutants. The greater the number of species — each with its own specialty — the greater the reduction of pollution. Maintaining the breadth of native species is also vital for outcompeting invasives and controlling the growth of toxic algae blooms, which have been reported in every coastal U.S. state. Katie Suding, a professor of ecology and evolutionary biology at University of Colorado, Boulder, likened biodiversity to recruiting a well-rounded sports team. “Because it is rare for one species to do everything well, a team of species will result in greater benefits in multiple functions,” she said. “For instance, if I were coaching a soccer team, I’d not just pick quick and fast players, but would want some to be strong and tall, and I’d want ones that could pass as well as take the ball to the goal.” Our health

anyaberkut via Getty Images Spending time in a park can help improve your mental health, according to research.

The whole “nature is good for you” thing might sound hokey, but it’s true. Spending time in nature — even just walking through a city park on your lunch break — improves mental health. People who have bird feeders in their backyards or hear birdsongs in their neighborhood are happier, instantaneously and over time, Dayer said. Plants have always been an important source of medical treatments, and that’s as true in today’s world of pharmaceutical research and development as in traditional medicine. Of all the new drugs approved in the last 30 years, about half were derived, directly or indirectly, from nature. This includes vaccines and vital cancer treatments. In addition to treating disease, biodiversity also plays a role in how it is transmitted. “I live in a place where I’m really worried about Lyme disease,” Halvorsen told HuffPost. Many of us can relate. Cases of Lyme (as well as other tick-borne diseases) have increased as much as 1,300% in some parts of the U.S. Some researchers believe that greater biodiversity may dilute human exposure to Lyme. The same is thought of malaria. The lives we live

Vincent Pommeyrol via Getty Images Coral reefs have among the highest levels of biodiversity of any ecosystem on the planet, and they also function as natural barriers against storms.

Robust biodiversity protects our very ways of life. Coral reefs and mangroves are natural barriers against storm surges. Mixes of grasses and plants with different root systems prevent soil erosion, which can destroy farmland, pollute waterways and lead to devastating floods. Diverse forests are more resilient to fire. Whole societies depend on thriving livestock or seas teeming with fish. Our relationship with nature says a lot about who we are, and who we want to be. Maybe your parents used to take you out fishing. It’s a family tradition you planned to pass down to your kids. Well, Halvorsen warned, “you might not be able to do that if the live insect species those fish need to eat have been reduced.” Between warming waters, pollution and the decimation of insect populations — 41% of insect species are in decline — that simple pastime may no longer be a given.