science education Archives - Page 10 of 10

Posted on August 6, 2021September 4, 2026 by Valerie — 6 Comments

Food Chains vs Food Webs: definitions, differences explained, and examples

Maybe you’ve studied a little ecology and come across the terms “food chain” and “food web.” Both help ecologists explain the ways that energy from food travels through an ecosystem. In this post, we will dive into the differences between food chains and food webs, and look at some examples of both!

Before we dive in: If you’re an educator planning to teach food webs, great activities are key to deepening understanding! I think you and your students will love my Food Webs Unit (plus you’ll support my blog with your purchase! ❤️)

Food Chains

In an ecosystem, organisms are connected through feeding relationships: basically, who eats whom. There are feeding relationships between plants and plant-eating animals and feeding relationships between prey and predators. A food chain is an ordered list of who eats whom in an ecosystem. It is just one of the many paths that allow energy to move through an ecosystem, from organism to organism.

Food chains will always start with a producer: a plant or microorganism that can make its food through photosynthesis, creating sugar and oxygen from water, carbon dioxide gas, and sunlight. The next organism on every food chain will be the primary consumer – a plant-eating animal, also known as an herbivore. Following the primary consumers are one or more additional consumers, called the secondary (2nd) consumer, tertiary (3rd) consumer, quaternary (4th) consumer, etc… Secondary and higher consumers will always be omnivores or carnivores. The final consumer on any food chain is also known as a top predator because it has no predators of its own.

Food Chain Diagrams:

We visually represent food chains with a list of organisms connected by arrows to show the movement of energy through food (see above). Food chains are also sometimes represented as pyramids (see below) because it takes many producers to feed each primary consumer, many primary consumers to feed each secondary consumer, and so on. This is why ecosystems have many plants but few top predators. Each layer on the pyramid represents a position in the food chain, called a trophic level.

A food chain pyramid diagram with labels — A pyramid food chain diagram reminds us how it takes many organisms in lower trophic levels to support just a few organisms in higher trophic levels.

Food chains vary in length. Some may be short, with as few as two trophic levels. Others have more trophic levels due to many different producers eating one another. Below, you will find a few examples of food chains.

Food Chain Examples:

Clover -> Rabbit -> Fox

Willow -> Elk -> Wolf

Leaf-> Grasshopper -> Songbird -> Owl

Flower nectar -> Butterfly -> Frog -> Heron

Phytoplankton -> Bivalve -> Walrus -> Orca

Algae -> Caddisfly larva -> Minnow -> Salmon-> Bear

Food Webs

A food chain is just one of the many paths that allow energy to flow through an ecosystem. However, ecosystems are more complicated than a single food chain: every ecosystem includes many overlapping and interconnected food chains. For example, several different herbivores might all graze on one large field of grass. One predator might eat several types of prey to get enough food. The result is a complex network of feeding relationships between organisms in an ecosystem, called a food web. Food webs map the many paths for the movement of energy between all the organisms in an ecosystem.

In addition to the producers and consumers, decomposers are an important part of any food web. Decomposers are ecosystem members who have an important role in recycling organic matter back into the soil. They consume waste and decaying plant and animal matter. Usually, decomposers are fungi, microorganisms, or invertebrate animals like worms. Thanks to decomposers, nutrients are returned to the soil to help plants grow.

The difference between food chains and food webs? In summary, food chains are a single path showing how energy moves from organism to organism through an ecosystem, while a food web is a more complex network that maps the multiple feeding relationships of each organism in an ecosystem.

Food Web Example:

An example diagram of a food web including decomposers, producers, consumers, primary, secondary consumers, and tertiary consumers!

Build Your Own Food Webs:

For a fun, hands-on way to teach students about food webs, try creating models of food webs in your classroom! Read my post about building your own food web models for step-by-step activity directions! Or, you can find all the printable materials, directions, and worksheets for this activity in my complete Food Webs Unit:

Food Webs: an ecology unit with hands-on activities!

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Free Food Web Learning Materials:

I’ve created a few free food web learning materials that you can download and print! My email newsletter subscribers can access and download my full collection of free worksheets, handouts, and diagrams, including these:

Access the free resources: my newsletter email subscribers can access my ENTIRE collection of free resources!

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If you haven’t already, try out one of my ecology units!

Deserts: an ecology and earth science unit

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Macroinvertebrates: a hands-on aquatic ecology unit!

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Pond Ecology: an environmental science unit for kids!

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Forest Ecology: an environmental science unit

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References and Further Reading

EPA (n.d.). EPA EcoBox Tools by Exposure Pathways – Food Chains. Available: https://www.epa.gov/ecobox/epa-ecobox-tools-exposure-pathways-food-chains
National Geographic (n.d.). Food Web. Available: https://www.nationalgeographic.org/encyclopedia/food-web/
National Oceanic and Atmospheric Administration (2019). Aquatic Food Webs. Available: https://www.noaa.gov/education/resource-collections/marine-life/aquatic-food-webs

Posted on March 30, 2021August 25, 2026 by Valerie — 16 Comments

The Water Cycle: How it works, a simple and detailed explanation with definitions, diagrams, and a visualization activity!

a banner with a hand drawn water cycle diagram and a classroom handout on a table with measuring cups

Author’s note: As a master’s student who works with water, this is an exciting topic for me to write about! Water is a vital resource that needs careful management in the Mountain West region of the United States. Mountain region watersheds are expected to face climate change-related challenges due to decreasing winter snowpack, changing stream flows, and growing downstream human settlements. Understanding our watersheds and the challenges they are facing is very important, not just for scientists but for everyone. It is never too early or too late to start learning about environmental processes like the water cycle that make life possible for all beings. This is truly a force of nature that impacts all of us, regardless of where we live or our occupations. We all use water, and we all can find ways to use water more sustainably, work to ensure everyone can access reliable and clean water resources, and protect aquatic ecosystems (which provide some cool ecosystem services… this will be a topic for another post soon!)! The water cycle is so huge and important, I’ve decided to make a whole series of posts about it. My goal in writing this first part is to overview the water cycle in a straightforward but detailed way – not just for science students but for anyone and everyone who is curious about our Earth’s water cycle. In the second part, I plan to introduce some of the ways humans impact the water cycle, and steps we can take to better use and manage our water resources and ecosystems. I hope this two-part post provides you with some useful background information about how the water cycle works and how we interact with the water cycle. I’ve also included some free digital learning resources related to the water cycle, linked at the bottom of this article!

In a rush? Click here to skip to the free learning resources!

Try this water cycle learn-at-home science activity for kids

What is the water cycle?

Ever wondered what keeps our streams flowing? Or why rivers don’t run out of water? Or where does the water bubbling out of the ground at natural springs come from? The answer to all these questions actually begins with our sun! The sun is like an engine, providing the necessary energy to drive the water cycle. The water cycle is an ongoing process of moving water from the oceans to the land and back.

The Water Cycle diagram – Download and print this diagram!

The water cycle begins over our oceans, where the energy from our sun causes huge amounts of water to evaporate every day. When water evaporates, it doesn’t disappear – it becomes water vapor: water in gas form rather than liquid form. Ocean water can evaporate, but salts in the ocean cannot. Because salt cannot evaporate, evaporation separates freshwater out of the ocean. Freshwater is non-ocean water that is usable by land plants and animals, including humans! Evaporation is an important Earth process that makes human life possible because it separates the freshwater from the saltwater.

Sunset over an ocean beach — The sun fuels the water cycle by providing the energy for water to evaporate

As the evaporated water vapor rises up in the atmosphere, it cools and condenses, or starts forming tiny liquid droplets. As larger droplets form, they fall from the clouds as precipitation, such as rain or snow. Most precipitation will fall directly back into the ocean. However, sometimes clouds that form over the ocean will move over a continent and precipitation falls on the land. When rain falls on the land, some of it flows over the surface of the land, which we call runoff. Little streams may flow into larger streams and rivers, or temporarily be stored in non-moving bodies of water like ponds and lakes. Any water on the earth’s surface, including streams, rivers, ponds, lakes, and oceans, is called surface water. Ultimately, all surface water will do one of three things: evaporate again, flow all the way back to the ocean, or infiltrate…

Large storm clouds over mountains in Colorado. — Precipitation falls over the Rocky Mountains, beginning its long journey back to the oceans.

To infiltrate, in other words, means to seep into the ground. When water infiltrates, it fills the tiny gaps in the soils and rocks below our feet! This water is called groundwater! In the water cycle, water may infiltrate into the ground at any point between where it falls on the land as precipitation and when it flows back into the ocean. Like surface water, groundwater also moves or flows, but much more slowly than surface water. Some groundwater bubbles back out of the ground onto the surface in a spring or a gaining stream: a stream that is fed by groundwater rather than runoff. Plants will also take up groundwater through their roots and release it back into the air as water vapor through the tiny pores in their leaves, in a special type of evaporation called transpiration.

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The Water Cycle: a science unit + hands-on lab activities!

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So far, we’ve looked at water in liquid and vapor forms. But what about water in solid form such as ice and snow? It turns out ice and snow play an important part in the water cycle too. When snow falls on land, it can build up in one place, or accumulate. When temperatures increase, such as in springtime, the snow that built up through the winter will melt and flow into our surface and groundwater. In certain cold and snowy areas, such as in tall mountains or near the poles, snow accumulates faster than it melts. This forms glaciers and ice sheets: long-lasting bodies of ice, made from compacted snow. Most of the fresh water on our planet is currently stored as ice in glaciers, ice sheets, and snow! Scientists in the field of snow hydrology study these important stored waters!

Looking back down from Byron glacier in front of snow-capped mountains — Glaciers, such as this one near Anchorage, Alaska, are an important place where fresh water is stored in the water cycle

Saltwater, like ocean water, is toxic to humans and land plants and animals. All the water we drink, bathe in, clean with, and use to grow plants must be freshwater. Freshwater is only a tiny fraction of the water on Earth: about 97.5% of Earth’s water is saltwater. That means only 2.5% of the Earth’s water is freshwater. Of that 2.5% freshwater, most is not usable by humans. Over two-thirds of the Earth’s freshwater is frozen in glaciers, ice caps, and snow, and a little less than a third is groundwater. Surface water like rivers, lakes, and ponds is just a fraction of a percentage of Earth’s total freshwater – and just a tiny part of a fraction of a percentage of Earth’s total water overall! If you’re having trouble visualizing this, check out the free at-home activity guide to help you and your child or students visualize the percentages of freshwater from home in the kitchen or bathtub!

Continue to Part 2 of this post about the water cycle – covering the ways humans interact with the water cycle!
Skip to Part 3 about the water cycle – covering the role of mountain watersheds!
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Free Project: Water on Earth’s Surface

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References and Further Reading

Plummer, C. C., Carlson, D. H., & Hammersley L. (2019) Physical Geology. New York, NY: McGraw-Hill Education. (16th ed., pp. 232 – 320).
U.S. Geological Survey. (n.d.). How Much Water is there on Earth? Available: https://www.usgs.gov/special-topic/water-science-school/science/how-much-water-there-earth?qt-science_center_objects=0#qt-science_center_objects

Posted on March 16, 2021August 7, 2021 by Valerie — Leave a comment

An Invitation

A banner of a student using forceps to collect insect samples from a tray of pond material, overlaid with text: "unique learning resources to spark curiosity about the natural world" and "visit Wildearthlab.com"

Looking through a lake sample for aquatic insects.
A monarch butterfly caterpillar munches on milkweed.
A tiny red-spotted newt crawls across the forest floor.

Welcome fellow nature lovers and outdoor adventurers. Welcome backyard naturalists, kitchen table scientists, life-long learners. Welcome fellow wonderers and wanderers. I’m glad to see you here.

My name is Valerie and I’m a scientist, artist, and avid outdoors woman currently in Colorado, USA. My curiosity about the natural world started at a young age, exploring the prairies and woods of Wisconsin where I grew up. This curiosity blossomed into a love of backpacking and hiking as a teenager, which inspired me to embark on what I saw as the ultimate outdoor adventure – a thru-hike of the 2,180-mile Appalachian Trail. This journey took me to places I had never been, where I experienced things I had only dreamt of: I saw my first-ever black bear, as well as moose, baby deer, copperhead snakes, songbirds, foxes, owls, turtles, and red-spotted newts. I marveled at wildflowers that grew above tree line in the White Mountains of New Hampshire. I witnessed seemingly tropical rhododendron plants comfortably survive two feet of snow in the Great Smoky Mountains. I forded rivers where no bridges had been built, bathed in lakes that had never seen a motorboat. I satiated my hiker hunger with wild blueberries.

Medium sized orange and brown turtle with its head tucked into its shell. — A box turtle.

Large round blueberries growing on a dense shrub with oval-shaped green leaves. — A box turtle.

I also saw many things I hadn’t expected to see, such as when the trail crossed through a superfund site in Pennsylvania. The area’s history of zinc smelting noticeably impacted the landscape, which abruptly changed from dense forest to barren hillslopes, eerily devoid of birdsong and inhabited by only a scattering of dying trees, invasive grasses, and more deer ticks than I care to remember. I saw firsthand the immense efforts of trail crews to remove litter at overrun shelters and privies. I experienced a mass emergence of invasive caterpillars along a section of trail in West Virginia. I encountered wild animals that were so desensitized by repeated human interaction and feeding that they approached hikers without fear. I witnessed restoration efforts to prevent the encroachment of lower-elevation species onto the mystical bald mountaintops of the southern Appalachians. I learned that the “100-mile wilderness” in Maine, known for being one of the most remote and wild areas on the east coast, is also the site of several logging operations, providing the necessary resource for our wood and paper products. Through this experience I learned there was a lot I didn’t know about our natural world, the resources we extract from it, and the ways that we impact it.

Close up of two small gray caterpillars have eaten a leaf until only the fibrous leaf veins remain. — Caterpillars devour leaves.

An area of charred, blackened ground along a section of trail near the summit of a bald mountain. — Caterpillars devour leaves.

In part, my experiences along the trail inspired me to pursue a degree in Fish, Wildlife, and Conservation Biology. I felt motivated to better understand the natural world and our relationships with it. Through the eyes of a scientist, I learned. I learned about the big, seemingly-unstoppable cycles of nature – of water, carbon, tides, and seasons – so powerful and yet delicately balanced, to allow for the diversity of life on this planet. And I learned about the small, unlikely relationships existing between pairs of species – between flower and pollinator, bird and fruit-bearing tree, plant and mycorrhizal fungus – allowing both to thrive. I learned about the unseen connections of all beings within an ecosystem, and about how we humans are connected to this world too, even when our lives make it difficult to see the places we are attached.

In the past few years, I have worked as a scientist in both the field and in the laboratory. I’ve measured the flows of headwater streams, counted new seedlings in beetle kill forests, evaluated the health of insect communities in a national park, and studied soils following forest fires and chemical spills. As a scientist, I’ve had the opportunity to intimately understand our relationship as humans with nature: what we are doing right, what we are doing wrong, and how we can do better.

An ecologist in hard hat, goggles, and brown utility vest stands in a forest and writes notes in her field journal. — Taking good field notes is key!

Tiny green humming bird with a long pointy beak and white tail feathers lies on its belly on a scientist's outstretched palm. — Taking good field notes is key!

Throughout my education and career, I have wondered how things would be different if education about nature and our relationship with Earth started earlier. My childhood education barely scratched the surface of ecosystem science, and it wasn’t until college that I was introduced to sustainability and conservation. What could our world be like if we all started out with a better understanding of this Earth and all its wild, remarkable, intricate beauty? How could things change if we all carried with us an understanding of the things we can do – big and small – to improve our relationship with Earth? I believe one of the most natural things we can do as humans is to wonder at nature. It’s never too early – or too late – to start learning about the natural world, the diversity of life on this planet, and what we can do as individuals to help protect it.

Close up of tattered, damp pinecone help up in front of a forested background. — A Douglas fir pinecone.

Woman in waiters stands in a stream while using a hammer and level to adjust stream monitoring station equipment in a mountain valley. Grey smoke can be seen in the background, rising off of the mountainside. — A Douglas fir pinecone.

My goal in creating Wild Earth Lab is to create resources for you, your family, and your students to learn about the Earth and our relationship with it. Through combining my passions for nature, science, and art, I hope to use this space to create unique and beautiful educational resources and engaging, informative articles covering a range of topics related to science, sustainability, and the natural world.

Are you still with me? Perhaps this sounds like something you’re interested in too. I hope you will join me on this journey by subscribing to Wild Earth Lab, or by following Wild Earth Lab using the links below:

Tag: science education

Food Chains vs Food Webs: definitions, differences explained, and examples