← Nat Theo Nature Lessons Rooted in the Bible
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Imagine exploring the wonders of creation while growing in faith. Inside the NAT Theo Club, families discover God's creation through kid friendly science, devotional content, nature journaling, hands on activities, bonus videos and more, all rooted in Biblical truth with flexible options for ages 4 to 14. Your children can explore birds, insects, reptiles, plants and other wonders of God's creation at their own pace with new content added every week. Celebrate each discovery with certificates of completion in our brand new Bible and Nature unit Studies. The Nat Theo Club is a meaningful, wonder filled way to help your family reconnect the dots between creation and creator. Visit natheo.comclub to learn more. Hello world. Wake me up to another good good morning. Time to go. Are you ready to explore God's wild and wonderful world? Welcome to the NAT THEO Podcast. I'm your host Erin Lyneum. I'm a certified master naturalist, Bible teacher and author and I am so excited to dive into God's written word, the Bible and created world with you. Have you ever gone through a big change in life? Maybe you moved to a new home or began attending a new church or school? My husband and I have been married for almost 17 years and during that time we have moved nine times, sometimes just across town, but other times across the country. We've had four children, many job changes and many church changes. Along with our moves, big life changes can be exciting but also challenging. Today we are meeting an animal that goes through a very big life change twice. This animal makes a big move not only to a new area, but to an entirely new habitat. Let's uncover the mystery of how God designed salmon to move from freshwater to saltwater and back to freshwater. Here is our trail map. Are you ready? We are going to learn where do salmon live? How do salmon live in both fresh and salt water? Why do salmon swim upstream? And where is our true home? Before we hit the trail, let's thank our sponsor who helped make this lesson possible. Apologia. You can save 25% on all of Apologia's curriculum during their site wide summer sale@apologia.com My family has been wowed by God's fish and other underwater creatures as we adventure through Apologia's Swimming Creatures of the fifth Day Zoology course. Explore unique watery ecosystems filled with awe inspiring creatures like dolphins, sea turtles, urchins, squid and sea snakes. Discover God's designs as you read along and create your own ocean dioramas. Craft projects and experiments bring learning to life as you discover God's purpose and wisdom in his many magnificent underwater creatures. Save 25% on Apologia's site wide summer sale at apologia.com or at the link in our Show Notes. It's time for our trivia question. How many eggs does a female salmon lay? A up to 50, b up to 800, c up to 2000 or d up to 10,000? Again, how many eggs does a female salmon lay? A up to 50, b up to 800, c up to 2000 or d up to 10,000? Take a guess and we will find out at the end of today's lesson and Nat Theo Club members. After this lesson, click over to the bonus video where we will learn how salmon swim upstream and jump over waterfalls. Find that bonus video in your Nat Theo Club Dashboard or at the link in our Show Notes. All right, let's hit the trail. Have you ever seen a salmon? Maybe you have eaten a tasty, delicious salmon for dinner. Salmon are amazing fish and God designed eight different types of them. There are seven species of Pacific salmon. Five of those species live in North American waters and two of them in Asia. How many species is that? Well, five in North America and two in Asia make seven species. The eighth salmon species is different. It is the Atlantic salmon living in the Atlantic Ocean. Most of the eight species of salmon live part of their life in freshwater rivers and streams and part of their life in saltwater oceans. Most salmon are anadromous. Anadromous means an animal is born in freshwater, lives most of its life in the ocean, and then returns to freshwater to have babies. Here is how a salmon grows up. A mother salmon lays eggs in the gravel of a freshwater river. Those eggs hatch into tiny baby salmon called alevin. The baby alevin have a yolk sac attached to them which is the food that they need for this first stage of life. The yolk sac is a bit like a backpack full of snacks that you might take on a hike. Although it's not packed full of granola bars and meat sticks like your backpack might be. Instead, it's full of nutrients that the baby salmon needs to grow during this first stage of life. The yolk sac is often called the Alevin's bag lunch. Isn't that cute? The baby salmon uses its built in bag lunch for around a month so that it doesn't have to venture out and find food just yet. Instead, it can stay safely tucked into the pebbles as it grows. The baby alevin then grows into a fry. Not a french fry like you might enjoy eating, but a baby fish called a fry. They are a bit bigger now and the built in bag lunch is all used up, like when you run out of snacks on the trail. But this is not a problem for the salmon because the young fry can now find food for itself. Depending on the species of salmon, the young fry might head straight for the sea. But most species stay in the fresh water, continuing to grow for a few months to over a year. When the salmon grows big enough, it's time to head toward the ocean. To do this, it will go through some big changes. The fry will now grow into a juvenile stage called a smolt, through a process called smoltification. Smoltification is when a young salmon's body changes into ocean ready mode. It goes through a set of changes that helps a young salmon get ready to leave the freshwater and enter the saltwater. Its gills start working differently so that it can get rid of extra salt when it is in the ocean, which we will learn more about in a moment. And its body shape and color may change, often becoming more silvery. The young salmon smolt heads out to the ocean where it will spend most of its adult life in the salt water. Depending on the species, an adult salmon spends around one and a half years to eight years in the ocean. This means that you might spot a salmon when you're walking along a river in the mountains or the woods. And you also might spot a salmon on a boat out at sea. So salmon begin their lives in the freshwater river or stream and move out to the saltwater ocean as they get older. But how do they make such a big move? If you have ever visited an ocean, you might know how different saltwater is from fresh water. Us humans, we need to drink a lot of fresh water to stay alive, but we cannot drink saltwater. The difference between fresh and salt water matters a lot for animals. Fish and other creatures are made to live in one kind of water or the other. Their bodies are designed to handle the water that they live in. A freshwater fish living in an ocean would have a hard time with all of that salt. And a saltwater fish living in a river would have the opposite problem. So it is quite amazing what salmon are designed to do. Their bodies change as they grow so that they can live both in freshwater and and in salt water at different times during their lives. God made salmon able to move from fresh water to salt water and eventually back to fresh water again through a process called osmoregulation. Osmoregulation is how living things keep the water and salt in their bodies just right. Not too much and not too little. It's almost like salmon have a Switch in their bodies for living in freshwater or saltwater. It's not as simple as a switch, like an on off switch, of course, but we can picture it that way. Here's what is really happening through osmoregulation. Picture a salmon in a freshwater river. Freshwater has very little salt in it. A salmon's body has more salt than the fresh water around it. That means that the fresh water keeps trying to move into the salmon's body. And as it does, salt tends to wash out. So the salmon has to hold on to salt and get rid of extra water. It does this by taking in salts through special cells in its gills and making lots of watery pee to get rid of extra water. This is how a salmon keeps enough salt in its body when it's living in fresh water. Now picture a salmon living in the salty ocean. Saltwater has much more salt than the salmon's body. That means that water tries to leave the salmon's body and too much salt tries to get in. So the salmon has to keep water in and get rid of extra salt. It does this by drinking seawater and pushing extra salt out through its gills and making less pee. God engineered something very special inside a salmon's gills to help with this salt balancing act. Inside their gills are tiny salt special cells called ionocytes. Ionocytes are special cells in a salmon's gills that help control salt balance. Ionocytes are like tiny salt managers in the salmon's gills. They help move salt in or out of the fish's body so that the salmon stays healthy. Depending on what kind of water a salmon is swimming in, the inocyte cells can either help to take in extra salt and hold onto minerals or push out extra salt. In rivers, they help bring salt in, and in the ocean, they help send out extra salt. That is a lot going on inside of a salmon's body. But put simply, the salmon is designed to thrive whether it is in freshwater or salt water. We learned that salmon begin their lives in freshwater rivers or streams, and then grow up and venture out to the saltwater ocean where they live for one and a half to eight years, depending on the kind of salmon. But what then? It's time to have babies. God always meant for the rivers and oceans to be full of beautiful, helpful salmon. Listen to Genesis 1, verses 21 to 22. When God made the water creatures, so God created the large sea animals and every living thing that moves in the sea. The sea is filled with these living things, with each one producing more of its own kind. He also made every bird that Flies. And each bird produced more of its own kind. God saw that this was good. God blessed them and said, have many young ones so that you may grow in number. Fill the water of the seas and let the birds grow in number on the earth. God designed salmon to have babies so that there can be more salmon. And he engineered them to have babies in a very unique way. They take one more big voyage. When it's time to reproduce, salmon leave the salty ocean and they head back into the freshwater river. Their salt balancing system kicks into gear and helps them adjust back to the fresh water. Once salmon reach the freshwater stream, they stop eating. They rely on energy stored up in their bodies to swim upstream. Once the salmon reach their breeding grounds, the female makes a nest in the gravel. This nest is called a redd and is a small impression in the gravel riverbed. The female does not have a shovel, of course, and so she uses her own body to make this nest. She swims sideways along the ground and uses her tail to move stones. She lays her eggs in the nest, and at the same time, a male salmon fertilizes the eggs so that baby salmon can grow. The female covers the eggs with some gravel to protect them. What happens next is a bit sad in the case of Pacific salmon. So most of the species of salmon, the mother and father salmon, die shortly after spawning or laying and fertilizing their eggs. Their job is done. But think about this. God gave the mother salmon an instinct to cover her eggs with gravel, which protects them so they have a better chance of surviving and hatching. And when salmon die after spawning, they provide a whole lot of nutrients to the river and to the animals who live by it. You see, salmon do most of their growing in the salty ocean, where there are a lot of minerals and nutrients. It's kind of like vitamin pen packed water. And when they die in the river, those minerals from the ocean go into the soil and into the animals that eat the salmon. With their special life cycle, Salmon are kind of like vitamin deliverers, going to the ocean and collecting minerals and then bringing them back upriver to feed plants and animals. So although it's sad to think about salmon parents dying, we can be grateful for the health that they bring to the rivers and that before they die, they lay the next generation of salmon for this cycle to continue. Something I find very interesting is that the one species of Atlantic salmon does not always die after spawning. Some Atlantic salmon head back to the ocean after laying eggs and keep living and even return to the river to spawn again. Okay, here's the really amazing part. If we are not already wowed by salmon, when they leave the ocean to return to the freshwater river, it's not just any river that they can find. The salmon head back to the exact stream or river where they began their lives. They their journey can be well over 1000 miles. How does a salmon find its way across a thousand miles of ocean back to the river where it began its life, even years after it left that river? Scientists believe that salmon navigate or find their way using the Earth's magnetic field, like how birds likely use the magnetic field to find their way when they migrate across the skies. Once a salmon gets close enough to where they entered the ocean when they were young, they can smell home. Scientists believe that when the salmon was young and making its journey down the stream toward the ocean, it memorized the chemical smell of its stream. Now, as an adult, the salmon remembers that smell and follows it home. They head back upstream, which can sometimes be another few hundred miles to spawn. That is an amazing journey, and what an incredible design for the salmon to be able to find their way home and lay eggs so that more salmon can be born. And the cycle continues. God engineered salmon with a homing instinct. A homing instinct is the salmon's special ability to find its way back home to the stream where it was born, even after being away at sea for years. In a similar way, God has placed a homing instinct inside of us. Now, hopefully, as you grow older, you memorize the paths and streets in your neighborhood, and you know how to get home from a friend's house. But that's not the type of homing instinct that I'm talking about. God has tucked within us a deep desire to be at home with him in eternity. He made this big, wild and wonderful world for us to enjoy. But because Earth is cursed and broken by sin, he doesn't want us to live here forever. This planet won't last for eternity. But our souls, they do last for eternity. Because we are made in God's image. Inside of us, we know that this Earth is not all there is. Ecclesiastes 3:11 says, he has made everything beautiful in its time. He has also set eternity in the human heart. Yet no one can fathom what God has done. From beginning to end, God has set eternity in the human heart. And yet, because of sin, we deserve to be separated from God for eternity. But because Jesus came to die in our place, taking our punishment for sin, we have the opportunity to spend eternity with with God. And in his presence, God gives us A picture of eternity with him in Revelation 21. Listen closely. Then I saw a new heaven and a new earth. The first heaven and the first earth had disappeared and there was no sea anymore. And I heard a loud voice from the throne saying, now God's presence is with people and he will live with them and they will be his people. God himself will be with them and will be their God. He will wipe away every tear from their eyes and there will be no more death, sadness, crying or pain because all the old ways are gone. The one who was sitting on the throne said, look, I am making everything new. Isn't that beautiful? God will one day make everything new, restoring his perfect creation. And that can be our home inside our souls. We have a homing instinct to be with God in eternity. But listener, we need to choose to be there with him. And thankfully God tells us that exactly how to do that. Romans 10, verses 9 to 10 says, if you declare with your mouth Jesus is Lord, and if you believe in your heart that God raised Jesus from the dead, you will be saved. We believe with our hearts and so we are made right with God. And we declare with our mouths that we believe and so we are saved. Have you ever declared declared Jesus is your Lord and believed in him for salvation? If you have never made that decision to follow Jesus, today is a great day to do so. You can pray a simple prayer like Dear God, I know I have done wrong things that go against your ways. I deserve sin's punishment of death, but Jesus died to save me. Thank you for sending your son to rescue me. I choose to turn from sin and follow you. I am so excited to spend eternity at home in your presence. Help me to grow in faith as I follow you all the days of my life. If you have prayed that prayer or one like it, today there is much rejoicing and I am celebrating with you. I encourage you to talk with your parent or pastor or a trusted adult so that they can celebrate with you and help you understand what it means to follow Jesus and grow in faith. If you are already a follower of Jesus, let's rejoice today knowing that one day we will be home with God in His new perfect creation. It's time to answer a question from one of our listeners. Here is today's question. Hello, my name is Carolyn. I am almost nine years old. I live in Huntersville, North Carolina. My question is how do drongos imitate the sounds of other animals? Thanks for your question, Carolyn. Drongos are a small bird found mostly in Africa Central Asia and Australia. God designed the drongo bird to be very intelligent, and one way that it showcases its smartness is through mimicry. Some species of drongo birds imitate different birds alarm calls, tricking the bird into thinking it has seen something dangerous. When a bird hears a familiar warning call, they swiftly fly away from the danger. And once the other bird has escaped, the drongo who tricked it swoops in to steal any food the bird might have left behind. But how can drongos make these different bird calls? Many birds make sounds through a special organ called a syrinx. The syrinx branches out into two tubes resembling an upside down letter Y. As a bird inhales and exhales, air moves over vibrating membranes like stretchy parts in the syrinx, producing sound. Birds can control the pitch and volume of their songs and calls by tightening or loosening the membranes and exhaling air forcefully or gently. Drongos listen to and learn different songs and calls that they hear, and then they imitate these sounds to trick other birds. God designed these brainy birds to be quite the tricky mimics. Thanks for your great question, Carolyn. Stay curious about God's wild and wonderful world and not Theo Club members remember. After this lesson, click over to the bonus video where we will discover how salmon swim upstream and jump over waterfalls. Find that bonus video in your Nat Theo Club dashboard or at the link in our show notes. All right, it's time to answer our trivia question. How many eggs does a female salmon lay? A up to 50, b up to 800, c up to 2000 or d up to 10,000? The answer is D. A mother salmon can lay up to 10,000 eggs and in some cases even more. Not all of those eggs will hatch into baby Alevin salmon with their built in lunch packs, but we can be very grateful for the ones that do hatch. Grow up and head out to the sea. Now it's your turn to explore. Go look for fish with an adult. Explore the shore of a lake, pond or river. Can you spot the shiny scales of fish shimmering below the water's surface? Always be careful while exploring near water and watch and marvel at how God designed fish for their underwater lives. Thank you so much for listening. If you enjoyed this lesson on salmon, please take a moment to send it to a friend and subscribe. Rate and review NAT3 wherever you listen. Until next time, keep exploring God's wild and wonderful world. We are all looking for adventure. We are all looking for adventure. We are all looking for adventure. We are all looking for adventure.