Podcast 222 - Static Hiss

The gang discusses two papers that look at evolutionary changes in animal groups after the End Cretaceous Mass Extinction. The first paper looks at morphometric changes in shark teeth, and the second paper studies the evolutionary and biogeographic patterns of snakes. Meanwhile, Amanda “fixes” her audio, Curt goes biblical, and James is missing.

Up-Goer Five (Curt Edition):

Our friends talk about things that lived through a real bad time when a huge rock hit the big round place where we all live. The first paper looks at large angry animals that move through water and have pointed things in their mouths and soft bits where things have hard bits. We usually just find the hard pointed bits from the mouth because the rest of the body falls to bits when they die. So this looks at how these old hard bits change from before and after the big rock hit. What they found was that changes happened within groups, where some groups were hit hard and others were not. But if you look at all of the big angry animals, it looks like very little changes. The hard bits are doing things that look the same before and after the rock hit, but its different groups doing that.

The second paper looks at animals with no legs and looked at changes in where they live and how quickly they change over time. The paper finds that after the big rock hit, one group was able to move to a new place. This move seems to happen when they also start making more of themselves. It seems that, for this big group of animals with no legs, the big rock hitting may have helped this group. It seems like a new place opened up after the big rock and the group took over and did well. There are also changes that we see when it gets colder in the time way after the rock hit.

References:

Klein, Catherine G., et al. "Evolution and dispersal of snakes across the Cretaceous-Paleogene mass extinction." Nature Communications 12.1 (2021): 1-9.

Bazzi, Mohamad, et al. "Tooth morphology elucidates shark evolution across the end-Cretaceous mass extinction." PLoS biology 19.8 (2021): e3001108.

Podcast 221 - Ramble On

The gang discusses two papers that look at patterns of speciation and extinction and relate those patterns to shifts in climate. The first paper looks at how both plate tectonics and climatic changes have contributed to shifts in provinciality, and the second paper tests the link between dramatic temperature changes and large scale extinction events. Meanwhile, James cannot remember “that guy”, Curt does not like Oliver Cromwell, Amanda is in an abusive relationship with her cats, and we cannot stay on topic for more than 2 minutes.

Up-Goer Five (Amanda Edition):

Today our friends talk about how the change in hot and cold and places where rocks are over a very long time has changed the way things live. Or not lived. The first paper says that while we used to think that changes in the way the big rocks that stick out of the water that we live on is the most important thing for making different animals and green stuff live in different places. But it turns out that it may be changes in hot and cold that take a very long time to happen that is more important. Both things are important, but how it gets colder the more towards the top of the world you go is just a little more important. It really controls how things can live places. The other paper looks at changes in hot and cold and how that makes things die. It turns out that if it gets warmer faster, or colder faster, it makes things die. They have a real number of 5.2 bits, and it is at more than 10 bits every 1,000,000 years. It does not matter if it gets warmer or colder, it is the quick turn that matters, and the big jump in change. They say that we are already getting hot enough fast enough right now to cause lots of things to die, even if we were not killing them, which we are.

References:

Kocsis, Ádám T., et al. "Increase in  marine provinciality over the last 250 million years governed more by  climate change than plate tectonics." Proceedings of the Royal Society B 288.1957 (2021): 20211342.

Song, Haijun, et al. "Thresholds of temperature change for mass extinctions." Nature communications 12.1 (2021): 1-8.

Podcast 220 - The Bone Gnome

The gang discusses two papers that look at the fossil record of fishes. The first paper looks at the ontogeny of ancient lampreys, and the second paper investigates the impact genome duplication had on the evolutionary history of teleost fishes. Meanwhile, James finds a gnome, Curt has an adorable ghost problem, Amanda appreciates good music, and we are all back on our b#ll$h!t.

Up-Goer Five (Curt Edition):

Our friends talk about two papers that look at animals that live in the water and have hard parts on the inside. The first paper looks at some of these animals which have a round mouth. These animals today are very different as kids then as grown ups. As kids they live in the ground and pull food out of the water. As grown ups they move through the water and eat other animals. This paper looks at old parts of these animals from a long time ago to see if the kids always did this. They find that these very old animals did not have kids and grown ups acting so different. This means that having the kids do something different is a thing that is new, even though people have thought that these animals have always done this.

The second paper looks at the how animals with hard parts that move through the water had the bits inside them that store how to build them get a times two. When there are more bits that store how to build them, it makes the homes in the hard parts bigger. So you can use how big these homes are in the hard parts to learn something about how many bits these animals have. Using old hard parts from old animals and a tree that shows which of the animals are close brothers and sisters to each other, they look at when changes in how big these homes in the hard parts were in the past. And since how big these homes are tells us how many bits that store how to build them they have, we can also see how these bits are changing through time. People have thought that getting more of these bits may be why there are so many of these types of animals. This paper shows that it may not be that simple. The number of bits goes up first, but the number of new animals does not go up at that time. Instead, it happens after big changes in the world. It is possible that these bits may have helped in bringing the number of these animals up, but it alone does not explain it.

References:

Miyashita, Tetsuto, et al. "Non-ammocoete larvae of Palaeozoic stem lampreys." Nature 591.7850 (2021): 408-412.

Davesne, Donald, et al. "Fossilized cell structures identify an ancient origin for the teleost whole-genome duplication." Proceedings of the National Academy of Sciences 118.30 (2021).

Podcast 219 - Brachiopod Vape Bros

The gang discusses two papers that look at examples of cohabitation and unique ecological interactions in the Cambrian. The first paper looks at multiple animals living together in a hemichordate living chamber, the and the second looks at a potential example of parasitism on brachiopods. Meanwhile, James flips a coin, Curt has to live with some consequences, and Amanda ranks things from meh to bad.

Up-Goer Five (Curt Edition):

Our friends talk about two papers that look at animals which are living together, sometimes not because both animals want that. The first paper looks at these long animals with no legs that live together. There are two different types of these long animals living the in the same spot, which is a home that looks like the ones built by the bigger of the two long animals, but the home seems to be a bit too big. Because the small long things do not have bits that could cut off parts of the bigger long thing, they think that these two animals would have lived in the same spot and been just fine. Since the homes are bigger than either animal, it means we still have to figure out why the homes are so big. It could be that the bigger long animals could be kids and the homes were built by the grown ups for the kids to live in.

The second paper looks at these small long round thing that was found on these animals with hard parts on either side which sit on the ground in the water and pull food out of the water. The animals with hard parts could have these small long round things on them or they could not. The animals with hard parts that had these small long round things were smaller than the ones that did not. The way the small long round things were put onto the animals with hard parts makes it look like they are homes for other small animals that would take the food out of the mouth of the animals with hard parts.

References:

Zhang, Zhifei, et al. "An encrusting kleptoparasite-host interaction from the early Cambrian." Nature communications 11.1 (2020): 1-7.

Nanglu, Karma, and Jean-Bernard Caron.  "Symbiosis in the Cambrian: enteropneust tubes from the Burgess Shale  co-inhabited by commensal polychaetes." Proceedings of the Royal Society B 288.1951 (2021): 20210061.

Podcast 218 - FEET!

The gang discusses two papers that look at trackway fossils. The first paper uses a modern study to determine how many tracks are needed to get a reasonable estimate on the trace morphology, and the second paper looks at trackways from an early tetrapod and attempts to determine the likely trace maker. Meanwhile, James has thoughts on Luigi, Amanda gives the birds the bird, Curt regrets a burn, and everyone loves Christopher Walken’s line delivery in Ripper.

Up-Goer Five (Amanda Edition):

Today our friends talk about people walking on ground that is wet and animals with four legs that also had a long back end part. The first paper looks at how many people need to walk on ground that is wet before it is enough people to make the numbers good. It also looks at how different kinds of ground and different types of wet also change the way things look. There actually does not need to be too many people walking on ground that is wet before the numbers are good. That means it is easier to do this with things that are not live anymore. The second paper looks at animals with four legs that were walking around a long time ago. The paper does a good job of figuring out just what those animals with four legs probably were, and about how they walked. They also had a long back end that dragged on the ground. That also tells us about how they walked. But there needs to be more stuff done on these animals with four legs and their walking marks, as well as their legs, before we know exactly what the back end marks mean.

References:

Logghe, A., et al. "Hyloidichnus  trackways with digit and tail drag traces from the Permian of Gonfaron  (Var, France): New insights on the locomotion of captorhinomorph  eureptiles." Palaeogeography, Palaeoclimatology, Palaeoecology 573 (2021): 110436.

Belvedere, Matteo, et al. "When is enough, enough? Questions of sampling in vertebrate ichnology." Palaeontology (2021).

Podcast 217 - In the Thick of It

The gang discusses two papers with… honestly a pretty flimsy link connecting them together. The first paper looks at size shifts in the dinosaur group, Alvarezsauridae, and the other paper looks at beetle fossils preserved in a dinosauromorph coprolite deposit. Meanwhile, James finds that the third time is the charm, Curt struggles to segue, and Amanda has thoughts on ham.

Up-Goer Five (Curt Edition):

Our friends talk about two papers that are not as much the same as they had hoped. The first paper looks at a group of angry animals wear most of these animals got really big a long time ago. A few of these animals start getting small, and this paper looks at one of those groups of angry animals that gets small to try and see when and why they got small. This paper uses a study of how these different animals are sister and brother to each other and then looks at how the big these animals are and tries to see if there is a time when things start to get small. They find that these things start to get small at a time pretty late in the life of the group. This is also around the time that a lot of small animals who wear their hard parts on the outside and live in big groups first appeared. Since the angry animals have weird hands that look like they could move through the ground, it is possible that these animals got smaller and started eating these even small animals who live in big groups.

The second paper looks at a small animal that wears its hard parts on the outside that was found in shit. I have to use the word shit because it is the only word in the ten hundred most used words that can be used to tell you what this animal was found in. It was found in shit. The animal is broken up so it seems that the animal was eaten by a bigger animal who then pushed it out when that animal had a shit. This small animal is one of the best remains of one of these animals from so long ago, because the shit kept the animal parts from breaking down. Shit is a really great way to find parts of other animals because it keeps some of those parts from breaking down really well. Also, the small animals in this shit are found with other bits of green things that live in water and use sun to make food. This means that the animal which ate the small animals might have been trying to eat the green things and happened to grab a lot of those small animals who were also on the green things.

References:

Qvarnström, Martin, et al. "Exceptionally preserved beetles in a Triassic coprolite of putative dinosauriform origin." Current Biology (2021).

Qin, Zichuan, et al. "Growth and miniaturization among alvarezsauroid dinosaurs." Current Biology (2021).

Podcast 216 - Salty Tooth

The gang discusses two papers that look at ecological patterns in the Mesozoic. The first paper looks at ecomorphic trends in Triassic herbivorous tetrapods, while the second paper uses morphological and chemical evidence to estimate the behavioral patterns of Cretaceous mosasaurs. Meanwhile, James has ideas about electrolites, Curt has a 99% average, and Amanda manages to record an entire podcast while having vertigo (that last bit isn’t a joke).

Up-Goer Five (Amanda Edition):

Today our friends talk about where and how things live. The first paper looks at all kinds of animals with four feet that eat green things from the first part of the age of big angry animals with lots of teeth and no hair. This paper is trying to use the parts of the animal's face to see how they eat. There are different kinds of ways to eat green things, and some ways of doing things have more types of these animals with four feet than others. They also find that there are big changes that happen at some times in different groups of these animals. The second paper is really cool and looks at big angry animals with hard skin that go back to the water. This paper shows that these big angry animals, which live in water that isn't good to drink, sometimes go to places where there is more water that is good to drink. Some go back to water that is good to drink every 4 to 7 days if they live in one place, or 12 to 20 days if they live in the other place. It is possible that these big angry animals with hard skin that go back to the water might have also gone from top of the world towards the middle of the world over longer times, and back again, like animals with light bodies and no teeth and no hair, but they are not sure here, they need to look more.

References:

Taylor, Leah Travis, et al. "Oxygen  isotopes from the teeth of Cretaceous marine lizards reveal their  migration and consumption of freshwater in the Western Interior Seaway,  North America." Palaeogeography, Palaeoclimatology, Palaeoecology 573 (2021): 110406.

Singh, Suresh A., et al. "Niche partitioning shaped herbivore macroevolution through the early Mesozoic." Nature communications 12.1 (2021): 1-13.

Podcast 215 - Ostensibly a Science Podcast

The gang discusses two papers that are loosely connected by the fact that they include mammals. The first paper looks at the biomechanics of a type of sabre tooth cat. The second paper analyzes the stability of mammal communities in deep time. Meanwhile, James loves the fans, Amanda is hemmed in by sound, Curt tries to avoid a lawsuit, and everyone really bungles explaining a paper on what is supposedly a scientific podcast.

Up-Goer Five (Curt Edition):

Our friends talk about two very different papers that are still about things with hair that are warm. The first paper looks at some of these animals with hair that had a set of very long teeth in their mouth that look like things we use to cut people. These animals all had many different types of long teeth, but we usually thought that they might be doing a lot of the same things just because so few other animals with hair get sets of teeth that long. This paper looks at the other parts of one of these animals with long teeth and finds that it is very different from many of the other animals with long teeth. A lot of animals with long teeth could run quick for a short time, while this animal looks like it could run for long times. This animal looks like it could chase things for a longer time, while the other animals with long teeth may have surprised their food. This is cool because it means that animals may have got long teeth for different reasons.

The second paper looks at groups of animals living together and sees how those groups change over time. They are looking to see if those groups can stay more or less the same across a long time, and also what helps these groups to not change. What they find is that in the area they are looking, there are three different groups that form and more or less stay the same until they suddenly change. These sudden changes happen when the world around them changes a lot. The groups remain more or less the same though before these really big changes in the world. Also, the groups can remain more or less the same even if the animals in those groups change over time. The thing that seems to be important in keeping these groups more or less the same is how the groups are built. Groups with a lot of different jobs for animals to do seem to be better at staying more or less the same over a long time.

References:

DeSantis, Larisa RG, et al. "Dietary ecology of the scimitar-toothed cat Homotherium serum." Current Biology (2021).

Blanco, Fernando, et al. "Punctuated ecological equilibrium in mammal communities over evolutionary time scales." Science 372.6539 (2021): 300-303.

Podcast 214 - Dead Mammals

The gang discusses two examples where extinction may have been very important in directing the evolution of mammals through time. The first paper looks at the impact of other mammals groups on the morphology of earlier therians, and the second paper looks at how extinction could explain some of the patterns observed in the Great American Interchange. Meanwhile, James learns some things, Curt steps out, Amanda imagines the end.

Up-Goer Five (Amanda Edition):

Today our friends talk about animals with hair. The first paper talks about animals with hair, and that ideas were had a while ago about how old kinds of animals with hair just weren't as good as new kinds of animals with hair, and that the very big angry animals with lots of teeth and no hair made the animals with hair from the same time stay small and not good. But it turns out that even after the very big angry animals with lots of teeth and no hair went away the animals with hair were still all very much the same and didn't do anything fun until much longer after the very big angry animals with lots of teeth and no hair were gone. That means that the very big angry animals with lots of teeth and no hair didn't really keep the animals with hair from being any good. The other paper talks about animals with hair from the upper part of the colder area of land in the "new" half of the world (which is not new but that's the only word we can use in this stupid word thing) moved into the usually warmer lower area of land in the "new" half of the world. It talks about how upper animals with hair moved into lower areas of land, and how lower animals with hair moved into upper areas of land. However, more upper animals moved into lower areas of land. And they wanted to know why. It turns out that more animals with hair that lived in the lower part of the "new" half of the world were dying as the places changed and got colder. We used to think just that it was upper animals with hair were better at living than lower ones, but that isn't true. It's just that there was space for upper animals to move in, and they could use the area better than lower animals with hair that moved to the upper part of the "new" half of the world.

References:

Carrillo, Juan D., et al.  "Disproportionate extinction of South American mammals drove the  asymmetry of the Great American Biotic Interchange." Proceedings of the National Academy of Sciences 117.42 (2020): 26281-26287.

Brocklehurst, Neil, et al. "Mammaliaform extinctions as a driver of the morphological radiation of Cenozoic mammals." Current Biology (2021).

Podcast 213 - Bringing our C Game

The gang discusses two papers about unique adaptations in the fossil record, the first is a paper about pterosaurs that have opposable thumbs and the second paper talks about burrowing synapsids. Meanwhile, Discord is silencing James, Amanda fact checks, and Curt messes everything up…. like EVERYTHING.

Up-Goer Five (Amanda Edition):

Today our friends look at some things that make very old animals that are not close to other animals look like those other animals. First our friends talk about an animal that had a very long ring finger with long skin on it and could fly. This is a pretty early animal that had a very long ring finger with long skin on it. People have thought that maybe animals that had a very long ring finger with long skin on it lived in trees. A new animal was found that had a first finger that can move across from the others, like people have on their hands. This means that this animal that had a very long ring finger with long skin on it could grab onto trees and hold them, which means they probably did live in trees. The second paper our friends look at looked at very old animals that had hair. Some of these are not even really animals that have hair like the ones that live today, because the three hard pieces inside the ear are not all the way in there yet. But these animals that had hair had some things that are like each other, because they had very big hands with heavy hard pieces in them that means they move in the ground. They push the ground around and are found under it. These are the oldest kinds of animals with hair that do this, and they also do some strange things with their hard bits that make up their back. This might be a thing that animals with hair living under the ground just do.

References:

Zhou, Xuanyu, et al. "A new darwinopteran pterosaur reveals arborealism and an opposed thumb." Current Biology (2021).

Mao, Fangyuan, et al. "Fossoriality and evolutionary development in two Cretaceous mammaliamorphs." Nature (2021): 1-6.

Podcast 212 - Ruining T-Rex

The gang discusses two papers that talk about T-Rex, and also the interesting way that these papers were discussed in popular culture. The first paper looks at the walking speed of T-Rex, and the second paper estimates how many T-Rex could have lived on Earth at any given time. Meanwhile, James is so very tired, Amanda loves soap, and Curt picks the worst transitions.

Up-Goer Five (Curt Edition):

The friends talk about a big angry animal that a lot of people know about. The first paper looks at how quickly that big angry animal could walk. Most animals with four legs / arms all walk about as fast as each other, even if the animals are big or small. Early work had made it seem that the big angry animal may have walked faster than the animals today. These early papers were looking at the foot falls of these big angry animals. This new paper looks at the big long part that comes off the end of these angry animals. The paper says that these big angry animals walked about as fast as any animal today even though they were big and angry and walked in a funny way.

The second paper tries to use the parts of these big angry animals that have turned into rocks to try and figure out how many of these big angry animals may have been living at any given time. It looks at how many animals we see around today to do this, and sees that the number of animals may be controlled by how much food the animals need to keep eating. Some animals burn a lot of food which means there can not be as many of them in an area. This means you can use how much food an animal burns to try and figure out how many animals could have been living in an area at any time. So they use this and some other numbers to try and figure out how many of these big animals were around in the past. This also allows them to figure out how many of the big angry animals may have been covered in ground and have their parts turned to rocks and how many were not.

References:

Marshall, Charles R., et al. "Absolute abundance and preservation rate of Tyrannosaurus rex." Science 372.6539 (2021): 284-287.

van Bijlert, Pasha A., AJ ‘Knoek van  Soest, and Anne S. Schulp. "Natural Frequency Method: estimating the  preferred walking speed of Tyrannosaurus rex based on tail natural  frequency." Royal Society Open Science 8.4 (2021): 201441.

Podcast 211 - Fossil Ecological Networks

The gang talks about two papers that look at changes in ecological interactions through deep time. The first paper looks at how ecological networks changed from the Permian into the Triassic, and the second paper looks at how echinoid diversity patterns compare to echinoid predation patterns. Meanwhile, James has some choice words about Elon Musk, Amanda’s stream is torn “into pieces”, and Curt once again would really like to start the second half of the podcast…

Up-Goer Five (Curt Edition):

Our friends talk about how animals and things that are not animals can build a place to live together, and how that changes over time. The first paper looks at how the places these animals and not animals build can change when things get really bad. It looks at two places in the past and uses numbers to see how these places change by getting more busy or less busy. They find that before most of the times when lots of stuff died, the places built by these animals and not animals were getting easy to fall to pieces. This is not true for this one time where things go really bad though, which is interesting and means that what was happening when things got really bad must be different.

The second paper looks at how a round animal in the water with hard hurt causing parts have changed over time and tries to see if being eaten caused some change. The paper finds that there are some changes that happen when we see these things get eaten, but also a lot of the changes are happening before we see these things get eaten.

References:

Petsios, Elizabeth, et al. "An  asynchronous Mesozoic marine revolution: the Cenozoic intensification of  predation on echinoids." Proceedings of the Royal Society B 288.1947 (2021): 20210400.

Huang, Yuangeng, et al. "Ecological  dynamics of terrestrial and freshwater ecosystems across three  mid-Phanerozoic mass extinctions from northwest China." Proceedings of the Royal Society B 288.1947 (2021): 20210148.

Podcast 210 - Mega Shark Doot Do Do Do

The gang discusses two papers that look at the ecology of the ancient shark Megalodon. One paper uses our knowledge of modern sharks to fill in the missing data on what Megalodon could have looked like, and the other looks for evidence of Megalodon nurseries in the fossil record. Meanwhile, Amanda cares too much, James spreads “facts”, and Curt would really like to find a segue.

Up-Goer Five (Curt Edition):

Our friends talk about two papers that are about a really big angry animal with large teeth that moved through the water and is known by a lot of people. This animal with big teeth lived a long time ago and would have eaten other really big animals. But because most of this animal is made of soft parts, we do not know a lot about what it would have looked like. So the first paper uses other animals which are very close to this big animal (but not as big) and see how they all look to see if bigger things look the same. They find that they can guess what parts of these animals should look like just by looking at their teeth, which is cool! They then use this to guess what this really big old animal could have looked like.

The second paper looks at how these big animals would have raised their babies. Some places where we get teeth from these big animals do not have a lot of big teeth, while other places do not have a lot of small teeth. This paper looks at these places to see if the change in how big the teeth are is important. They find that some areas really do have more small than big teeth. Some areas also have more teeth that are between being big or small. It seems that smaller animals (babies) lived in some areas, and then when they get bigger they move out.

References:

Herraiz, Jose L., et al. "Use of nursery areas by the extinct megatooth shark Otodus megalodon (Chondrichthyes: Lamniformes)." Biology letters 16.11 (2020): 20200746.

Cooper, Jack A., et al. "Body dimensions of the extinct giant shark Otodus megalodon: a 2D reconstruction." Scientific reports 10.1 (2020): 1-9.

Podcast 209 - Spacing Out

The gang discusses two papers that look at how animals take up space in a community. The first paper looks at ancient reef systems and uses spatial analysis to infer ecological interactions between corals. The second paper looks at the impact that lions have on other predators in South African reserves. Meanwhile, Amanda loves a number, James is an adult, and Curt has some strange ideas about pizza.

Up-Goer Five (Amanda Edition):

Today our friends talk about space. Not the cool space, with stars, but the space between animals. The first paper looks at tiny animals that form big groups that look like rocks. There are two kinds of tiny animals that formed big groups that look like rocks from a long time ago. In the first paper, it turns out that some of the tiny animals that formed big groups that look like rocks settle in a space and then make it better for other types of tiny animals that formed big groups that look like rocks. Sometimes we would think that these animals would fight and would not want to help each other, but it turns out that actually they might really need each other to live in a place. This paper uses new ways of doing things, so their stuff is really cool, but is also really new; it's never been done on tiny animals that formed big groups that look like rocks before, only on big tall green trees. So more stuff needs to be done with this new way of doing things. The second paper looks at large animals where boys have lots of hair around their heads and necks and the girls do all the work. The short of it is that when these large animals where boys have lots of hair around their heads are around, there aren't as many smaller things that eat other animals. But there seem to be more kinds of smaller things that eat other animals when large animals where boys have lots of hair around their heads and necks are around. So it is kind of weird.

References:

Dhungana, Alavya, and Emily Mitchell. "Facilitating corals in an early Silurian deep-water assemblage." (2020).

Curveira-Santos, Gonçalo, et al. "Mesocarnivore community structuring in the presence of Africa's apex predator." Proceedings of the Royal Society B 288.1946 (2021): 20202379.

Podcast 208 - Stable States

The gang discuss two papers that look at community structure in fossil and modern biota. The first paper looks at the size distribution of dinosaur communities and finds an interesting lack of mid-sized predators. The second paper looks at a modern kelp forest community to determine if fishing refugia results in ecological cascades in this system. Meanwhile, James is a magician, Amanda would rather be playing D&D, and Curt remembers Dino Riders.

Up-Goer Five (Curt Edition):

Our friends look at two papers that look at how animals live together in a place. The first looks at some very old and angry animals. When people look at how big these old angry animals are, they find something weird. If we look at all the angry things, we have a lot of big things, some small things, but not that much in the middle. When we look at that only eat things that get their food from the sun and see how they are different from the things that eat other animals, they find that this missing middle is because there are no middle animals in the things that eat other animals. One thought for why this could be is that some of the real big animals that eat other animals might have kids that fill the middle when they start to grow up.

The second paper looks at these places in the water that you can't drink where there are things that move through the water, things that move on the ground and have big hard things on them that come to points, and things that make food from the sun which are big and green. In a lot of places like this, if there are not some animals that eat a lot, the things with the points can eat all of the big green things. This place doesn't have one of those animals that eats a lot, but it was a place where people can not go in and grab some of the animals that move in the water. Since there are still big green things here, the people who wrote this paper wanted to see if the animals in the water were good at eating the animals with points. It seems that, while the animals in the water are doing better, so are the animals with points. This means that other things must be going on to let the big green things still be there.

References:

Malakhoff, Katrina D., and Robert J. Miller. "After 15 years, no evidence for trophic cascades in marine protected areas." Proceedings of the Royal Society B 288.1945 (2021): 20203061.

Schroeder, Katlin, S. Kathleen Lyons,  and Felisa A. Smith. "The influence of juvenile dinosaurs on community  structure and diversity." Science 371.6532 (2021): 941-944.