nature

Exploring Biodiversity

Olivia G. SchweikartLeave a comment

The value of biodiversity is that it makes our ecosystems more resilient, which is a prerequisite for stable societies; its wanton destruction is akin to setting fire to our lifeboat.

Johan Rockstrom

What is biodiversity?

The term biodiversity refers to the multitude of living species on Earth and their incredible variations. There are no exclusions for organisms when describing total global biodiversity, meaning organisms from all three domains of life are included. These domains are referred to as Bacteria, Archaea, and Eukarya. The relationships of these groups can be seen in the image below.

The three domains of life: Eukarya, Archaea, and Bacteria.

Members of Eukarya include eukaryotic organisms such as plants, animals, protists, and fungi. Archaea includes organisms such as retroviruses, and bacteria includes microbes such as E. Coli (a common cause of food poisoning). Archaea are unicellular organisms that lack a true nucleus (organelle that contains the genetic information of an individual), which distinguishes them from their nucleated counterparts Eukarya and Bacteria. Despite sharing similarities when compared to Archaea, members of Eukarya differ from Bacteria as these organisms are multicellular and have their organelles (functional parts of the cell) surrounded in individual membranes. Members of Archaea are commonly represented by those organisms that live in extreme conditions such as in the Dead Sea (‘salt-loving’ halophiles) or in volcanoes (‘heat-loving’ thermophiles).

Depending on the ecological system being described or studied, the scope of biodiversity might be confined to a particular location or groups of locations. When we describe the biodiversity of organisms at one particular location, we refer to this as an assessment of alpha diversity (α diversity). This measurement is particularly useful for understanding what mixture of species are present within an area.

For example, if you were to measure the alpha diversity of a park in city of Chicago, you may include up to a mixture of 155 species of birds depending on the location of the park, numerous insect species, plant species, etc. Regardless of the type of species, because we have established our area of study as the park, every living species within the park will be included in the alpha diversity assessment.

(C) Penn State | Insect Biodiversity Center

When multiple locations are taken into consideration, this becomes what is considered a beta-diversity (β diversity) assessment. This type of assessment can be incredibly useful when assessing large regions for biodiversity. For example, β diversity is beneficial for assessing the biodiversity of a country, or a large region of land such as a state. In this application, alpha assessments are taken at many different habitats, and compiled in a beta diversity application.

The scenarios given above for α and β diversities involve looking at an ecosystem level. These terms can, however, be applied to smaller scales, for instance looking at the biodiversity among a certain species (either from observable characteristic or genetic differences).

The video below is a great example at looking at species diversity within ants in the Gorongosa National Park (Mozambique, Africa).

How does biodiversity arise?

Within every organism, there is a sequence of genetic information that makes up every characteristic of that individual. From time to time, sequences must copy themselves in order to create new cells or pass on genetic information. A nature-made machine, editing enzymes are not perfect and occasionally make errors. These mistakes involve either adding in a base pair that doesn’t below (e.g., AATCG becomes AATGCG), removing a base pair altogether (e.g., ACGT becomes AGT), or swapping one base pair with another (e.g., ACCT becomes ACCG). Changes such as these can be fatal depending on the location of the change, or can have no effect on function. Occasionally, errors (also known as mutations) can alter a function within the organism without being fatal, resulting in a change of a visible characteristic. If these mutations are heritable (or within the cells to be used during fertilization), they can be passed on to new generations.

With new genetic potential, if a particular change in function is beneficial to an organism, these characteristics boost this individual’s chance for survival–heightening its chance of passing along this beneficial mutation to more offspring. Over time, accumulation of desirable characteristics in a population begin to shift the genetic pool available during mating events. Through directional selection, or a movement toward a beneficial trait in a population, these organisms become more similar to each other at the sequence where the mutation occurred. Errors in sequencing will continue over time, and those that occur in heritable cells (sperm, egg, etc.) might allow for survival against a new environmental factor, contributing to further shifting in genomic patterns and eventually allowing for the possibility of a new species with unique traits to emerge.

With enough geographic isolation or lack of gene immigration from outside populations, mutations in a population accumulate and eventually can cause populations of what were once the same species to now be genetically distinct enough to be considered different species.

What are the pressures that could shape an organism’s survival?

In the context of mammals, after the mass extinction of dinosaurs in the Cretaceous period (estimated 145.5 million years ago) a wide range of habitats became available for surviving creatures to colonize. One lineage became especially adapted to new modes of life, eventually extending a branch providing us humans (Homo sapiens) the opportunity to wonder about these foundational moments in history.

The video below is an illustration of the new habitats created for ancestral mammals and the selective pressures driving the adaptations needed to thrive in them.

Perhaps one of the most cited examples of colonization into new habitats is a case of adaptive radiation in Darwinian Finches (1800s). The term adaptive radiation refers to the same logic we set forth earlier, stating that organisms that invade available niches will have selective pressures from the environment on traits that encourage their success. Organisms with beneficial mutations or heritable abilities will survive, pass on their genetic information, and in turn a new species of organisms can emerge over time, now adapted to this new habitat.

Below is another HHMI BioInteractive video I recommend on evolution in Galapagos finches observed by Charles Darwin.

What is the significance of biodiversity?

Once biodiversity is established in an area, there are heavy consequences for its collapse. The greatest example of this is with the removal or eradication of keystone species. These organisms are foundational species for an area, meaning their presence keeps the living systems surrounding them regulated. When removed, the ecosystem shortly collapses. One example is the sea otter! As illustrated in the image to the right, when sea otters are present in their environment, barnacle populations remain at low sustainable levels, allowing lush kelp forests to grow and provide shelter for a wide array of aquatic biodiversity. When sea otters are removed from their environment, barnacle populations grow exponentially without predation, resulting in a reduction of kelp forests. Once home to many fish species, without kelp these organisms must find new homes, and as a result are either forced to leave the area or are exposed to predators and collapse themselves.

Non-keystone species also have ecological roles in their environment, which can cause domino effects for species that rely on interactions with them or something they were directly involved with. For instance, some caterpillars are known to take place in what is known as ecosystem engineering. This means the organisms are altering their environment in some way, which in turn can be useful for other creatures. In the case of caterpillars, many will create sheltered burrows in rolled-up leaf material. These burrows remain once the caterpillar no longer needs them, and is then used as a home for many different types of insects.

Regardless of ecological status, all species comprising our global biodiversity contain intrinsic value for their representation of millions of years of evolutionary lineages and evolutionary potential.

How is biodiversity conserved?

At the heart of the drive toward conservation rests governmental policy. Unfortunately, organized citizen by citizen efforts to be conscious about their environmental interactions are limited by the amount of people educational platforms and word of mouth can reach. Only through true government-mediated policy–be that local or federal–will large scale conservation efforts be able to go into effect.

Conservation laws specifically targeting keystone species are incredibly beneficial. Under these policies, not only is the habitat of that keystone species protected, you are in turn automatically conserving the habitat for the other species that occupy the area. The term for this is having an umbrella species, meaning the conservation of one implies conservation of a vast amount of other species. Umbrella species do not always have to be considered a keystone species, but do have to share habitat parameters with other organisms for them to be inherently included in the conservation efforts.

In situations where an organism is dwindling and is not considered an umbrella species, conservation efforts may not benefit other individuals, and thus more efforts may be required to conserve many species in a particular area. To get involved in the politics underlying conservation, it is encouraged to search periodically for bills being presented and contact your local representatives to express desires for the passing of these policies.

Ultimately, awareness within the general public of conservation-related issues and personal, consistent interaction with local government officials is the pathway for driving ecological reform.

Every individual can make a difference in the fight against biodiversity loss!

Ways to Get Involved with Conservation

1) Educate yourself. Stay up to date on current issues in conservation biology. To do this, there are a few options for quick-resources on the latest topics: Eco News Now | Phys Org | Nature Portfolio.

2) Contact your local officials! Stay up to date by searching for current conservations bills being presented to legislators, and make your desires known! To find your representatives, you can use this White House search tool.

3) Spread Awareness! Even if you cannot contribute at the moment, ambassadorship for conservation biology can spread to someone who might be able to.There is exponential growth with spreading the word! Even spreading information to two individuals on a Monday, if each person tells two other people the next day, you have the potential to have reached 254 people by the end of the week (see the figure below)!

An example of the impact of educational spread.

4) Volunteer your time. It is best to make an impactful difference in a chosen area, so be sure to not spread yourself too thin! Many organizations offer volunteer opportunities, such as local preservation chapters and zoos. To find opportunities in your area, quick internet searches are often very effective. To save time, Our Endangered World has created a list of opportunities and subsequent ways to find organizations. Visit this information here.

Citizen scientists in action! Photo Courtesy of the Urban Turtle Project | Birmingham, Alabama (est. 2018)

5) If you do not have time to volunteer, do not fret! There are many ways you can symbolically adopt animals, many of which are housed in zoos and other preservation agencies. Here are examples of symbolic adoption packages offered by WWF (World Wildlife Fund, Inc.).

6) Contribute to citizen science! Getting involved with citizen science projects is an incredible way to experience current research first-hand. One example in Birmingham Alabama, The Urban Turtle Project, allows citizens to help in the capture and counting of turtle species across the state. To learn more about this organization, you can follow this link.

For additional information on conservation biology and the importance of biodiversity, you can view the attachment videos following this article!

Stay Adventurous,

Olivia Grace

Additional Resources: Educational Videos

TEDEd Talk on the Importance of Biodiversity

Crash Course on Conservation and Restoration Biology

Diving Deep: the Fangtooth Fish

kmj0029Leave a comment

Anoplogaster cornuta, commonly known as the fangtooth fish, is a pelagic fish that grows to a maximum of 16 centimeters in length. Pelagic refers to aquatic organisms that can be found anywhere between 500 and 2,000 meters below sea level (see Figure 1).

With a name including ‘fangtooth,’ these organisms can be visualized as vicious predators within the deep ocean. Their elongated teeth bring about a fearsome visage. Certainly, to an unaware deep sea visitor, this fish may seem key to avoid. Despite its formidable name, the common fangtooth fish is hardly an eager, frightening hunter–in part to its small size, but also through its feeding behavior.

Habitat and General Description

Figure 1. Illustration of the habitable range (in meters) of the common fangtooth fish.

A. cornuta can be identified through its large caudal (or head) region and two milky eyes. These organisms have incredibly poor vision, which would be expected to pose a disadvantage, considering they dwell at incredible, poorly-lit depths. To combat this visual disadvantage, fangtooth fish possesses a highly developed lateral line system (see Figure 2). A lateral line is a sensory organ that runs laterally (horizontally) along the body and is highly sensitive to changes in the surrounding environment. This organ senses vibrations in the water driven by nearby movement, as well as changes in pressure.

Figure 2. Illustration of the lateral line location in the common fangtooth fish.

Highly developed lateral line systems, or those with high levels of efficient detection are useful for avoiding predation. In tandem with this form of defense, the common fangtooth has another useful mechanism to protect their lineage. These organisms have ultra-black skin, meaning their skin contains high concentrations of pigment that allow them to absorb nearly 100% of all available light! This allows the fish to hide in plain sight by blending in with its dark, deep surroundings (see Figure 3). 

Figure 3. A vintage photograph (film) of a collected, and dried, group of common fangtooth fish.
Figure 4. Illustration of gill components
and their functions.

Feeding Behavior and Morphology (Anatomy)

The most notable feature of the fangtooth fish’s morphology by far is its set of long, sharp teeth and cavernous jaw. In fact, the fangtooth has the largest teeth-to-body-size ratio of any known fish in the ocean. With record-setting lengths, how does this little fish close its mouth without puncturing its brain? The answer is with specialized pouches! These pouches are in the roof of the fish’s mouth and extend into deep sockets, allowing the teeth of its lower jaw to safely slide inside without doing harm to its noggin. Interestingly, juvenile fangtooth fish have much smaller teeth, and only a single row. As a result, juveniles filter feed zooplankton with gill rakes (bony or cartilaginous structures extending from the gill arch, see Figure 4) until they develop their name-worthy fangs.

As adults, fangtooth fish are opportunistic feeders, meaning a large portion of their hunting pattern involves consuming what happens to get close enough to capture. Indivudals of A. cornuta engage in diel migration, where they remain in the ocean depths during the day and migrate to shallower waters at night for feeding. Here, these organisms can enjoy a diverse diet of small prey that happen to get within range. Examples of prey include juvenile squid and juvenile or small adult fishes. Whereas these fish often consume prey at or beneath body size, these organisms have been known to consume prey much larger. Regardless of size, the fangtooth fish does indeed have poor visual acuity, and as a result relies on specialized chemoreceptors (or chemical sensing organs) to smell the organism underwater. Once a prey is obtained, it is unlikely to escape, making this fish an effective hunter should the opportunity arise.

Additional Resources

If you would like to learn more about this incredible species, you can view the BBC Studies Blue Planet video below titled: “Fangtooth in the Abyss.”

References

Monterey Bay Aquarium | Animals A to Z | Meet the Common Fangtooth

Monterey Bay Aquarium | Ocean Twilight Zone | Creature Feature: Fangtooth

Smithsonian | Ocean, Find Your Blue | Fangtooth Fish


Monotreme Monday: the Platypus

Kaleigh ArnoldLeave a comment

Welcome to Monotreme Monday! This platform is a short, written series focusing on the incredible adaptations of Monotremes!

Monotremes make up one out of the three main groups in the class Mammalia , where they are most popularly known for their egg-laying capabilities. In today’s edition of Monotreme Monday, we will be focusing on the Platypus, one of the five species of monotremes still alive today.

Once being a very popular character in Phineas and Ferb, Perry the Platypus was possibly one of the very first introductions of Monotremes for many. Although depicted as a blue, beaver tailed, duck billed creature in the show, the actual appearance of platypuses is more subdued.

© Hans and Judy Besage—Mary Evans Picture Library Ltd/age fotostock

The platypus, Ornithorhynchus anatinus, is endemic to most of the eastern Australian coast along with Tasmania and King Island, seen in Figure 1; there is also a small group of platypuses that were introduced to Kangaroo Island (Bino et al., 2019). As you can see from the map, a majority of recorded sightings from the Australian government atlas shows high concentrations of Platypuses at the southeastern coast where many permanent river systems span from tropical to alpine environments (Bino et al., 2019). The river systems allow for dispersal of young to new areas of their habitat, which is a common behavior seen often in juveniles ranging from 7-8 months of age (Furlan et al., 2013).

Figure 1. Distribution of Platypus based on Australian state government records between 1760-2017 (Bino et al., 2019).

Platypuses often inhabit areas near fresh bodies of water, including a range from fast moving streams to slow-moving pools with coarse layers of substrate on the bottom. The substrate usually consists of pebbles or gravel. Here, the platypus will create an underground burrow, constructed between mangled and submerged tree roots right above water level (Bino et al., 2019). An example image of what the burrows look like can be seen in Figure 2 and 3. The platypus diet primarily consists of aquatic invertebrates including insects, shrimp, and crayfish. Less often they can also be seen enjoying other aquatic animals, including tadpoles, small fish, and aquatic snails (Grant 2015).

Figure 2. An example of a Platypus burrow hole (Art done by  David Nockels © Look and Learn).
Figure 3. A platypus emerging from its burrow near a bank (Thomas et al. 2019).

Although classified as mammals, a number of characteristics reflected in the platypus can be see in fish, birds, and reptiles. Some of these characteristics include egg laying capabilities, venomous spurs, and an electroreceptive bill.

Egg laying is not a common character seen in mammals. In fact, this trait is one of the main classifiers for Monotremes. Female Platypuses will go through a gestation period of about 21 days, where the offspring will begin to develop. After the gestation period, the female will lay her eggs in the burrow, usually producing between 1-3 eggs each breeding season. The mother will then start the incubation stage, where the eggs will be curled up to the mothers abdomen and tail for about 10 days (Grant 2015). Offspring will then start to hatch from the eggs, breaking through the eggshell with teeth that will later be lost. After hatching, the babies will experience large scale developmental changes, including the development of a bill after five days, webbed feet after 24 days, and fur growing in within the first 11 weeks of life (Manger et al., 1998). For the first three to four months, offspring will remain in the burrow protected from outside dangers. Here they will start to feed on milk produced from the mothers mammary glands. These glands are located under the skin of the mother and occupy most of the abdomen . As the lactation period begins to close around 114-145 days after hatching, the juvenile platypuses will lose their teeth and replace them with grinding pads made out of keratin (Grant 2015).

All platypuses are born with venomous spurs that are used later in life. These spurs are present in both males and females when hatched, contained within a sheath until about 9-12 months of age. At that point, females will permanently shed these spurs while the males will retain them and start producing venom (Whittington and Belov 2014). It is speculated that males use these spurs primary during matting season, causing seasonal production of venom. The platypus is the only mammal currently known to produce venom seasonally (Grant 2015, Wong et al., 2012). Although capable of causing extreme pain, and in certain cases causing paralysis to other male platypuses, the venom will only be fatal to smaller animals (Bino et al., 2019).

One of the most well known features of the Platypus is the ‘duck-like’ bill. Although their bill can resemble that of a duck’s, it is actually much more similar to that of a shark’s nose. The Platypus bill is made up of a 40,000+ mucous receptor glands that can conduct electric signals and acts as an antenna when searching for prey. This type of electroreception has been originally observed in fish and some aquatic amphibians. Because of this, the Platypus uses its bill as a primary tool for hunting prey (Czech-Damal et al. 2013, Fjallbrant et al. 1998). The Platypus will rely solely on its bills electroreceptive capabilities while hunting underwater and because of this has a groove on either side of its head that will shut, concealing its eyes and ears underwater (Bino et al., 2019).

Figure 3. Up close look at Platypus bill and head (© San Diego Zoo Wildlife Alliance).

Unfortunately, the platypus has faced several threats over history starting in the late 19th and early 20th century when platypus populations were being hunted for their high quality fur. This was before scientific interest really took off, and only until 1912, when the platypus became legally protected, did studies of their unique anatomy and ecology start (Bino et al., 2019). Although there have been many studies done on the anatomy, ecology, and evolution of the platypus there has been little research interest in their conservation. The platypus faces many synergistic threats to its habitat including the increase in pollutants, changes in river/stream structure and hydrology, and the creation of dams and roads. Due to these issues, platypuses have been and continue to be displaced from their natural habitats and suffer consequences from the drastic change in its ecology (Bino et al., 2019). In 2016 the platypus was marked as a ‘Near Threatened’ species by the International Union for Conservation of Nature (IUCN).

There were several names the aboriginal peoples developed for the platypus, including ‘Mallangong’, ‘Tambreet’, ‘Gaya-dari’, ‘Boonaburra’, and ‘Lare-re-lar’. Along with these names, the aboriginal people also developed folk-lore that included biocultural and ecological connections to the platypus. One of the stories begin with Ancestral Spirits deciding on a totem’s formation. As the fish, birds, and marsupials of the land plead and reasoned with the platypus to join them in their group, the platypus consulted with an echidna and decided that it was not a part of any of these groups. The platypus explained to the fish, birds, and marsupials that since it shared traits with all the groups, it would remain friends with all of them instead of picking one identity over the other. Here, the platypus is commemorating the Great Spirit for its wisdom and creation of different animals (Bino et al., 2019).

Thanks for reading all about the wonders of platypuses! We hope to see you back for the next edition of Monotreme Monday!

Did you learn anything new? Feel free to share with us below!

References

https://ielc.libguides.com/sdzg/factsheets/platypus/summary

https://www.britannica.com/animal/platypus

Bino, G., Kingsford, R. T., Archer, M., Connolly, J. H., Day, J., Dias, K., … Whittington, C. (2019). The platypus: evolutionary history, biology, and an uncertain future. Journal of Mammalogy, 100, 308–327.

Diving Deep: the Anglerfish

kmj0029Leave a comment

The Anglerfish, to some, is a true deep-sea nightmare–and not just to Marlin and Dory on their search for Nemo! This species was discovered in 1833 by an English naturalist named James Yate Johnson. At the time of discovery, not much was known about the ecology and lifestyle of this ghoulish fish, as the only details came from deceased specimens. Whereas in recent years deep-sea divers have added much to our compendium of anglerfish, much of their lifestyle is still shrouded in mystery. There are over 200 species of anglerfish extant today, varying in lifestyle and size, but they all have one thing in common: an elongated cranial spine tipped with a bioluminescent organ. 

Most anglerfish live in the bathypelagic region of the open ocean—in other words, they live in the deep, dark, and cold regions, about 2000 m (6600 ft) below the surface. In complete absence of light with scarce food in the ocean depths, these ambush predators evolved their own ways to hunt and survive—by underwater fishing! The anglerfish uses its modified cranial spine to imitate other organisms in the darkness, with the photophore at the tip using a process of bioluminescence to create a blue-green light to lure in other small marine animals. Once a prey fish is in adequate range, the anglerfish will use its powerful jaws to suck in its meal whole. Though some anglerfish can reach up to four feet long and 110 pounds, most are fairly small. Despite this stature, members of this species are known to be able to swallow prey twice their size.

Museum specimen of an Anglerfish, genus Acentrophryn; image taken by Hongseok Kim in Seoul, South Korea.
Museum specimen of an Anglerfish, genus Ceratias; image taken by Hongseok Kim in Seoul, South Korea.

The bizarre appearance and predation style of anglerfish aren’t the only factors that make these fish so interesting. In fact, one of the most fascinating and unusual practices of some anglerfish species is their disturbing mating habit! For around 90 years after the first anglerfish was discovered, scientists and researchers were baffled as the only anglerfish they were finding were all females. That’s right, every anglerfish with a lure is female! These females were sometimes found with small growth like fish attached to their bellies and were believed to be their offspring. The behavior and ecology of male anglerfish were a total mystery until 1924 when Charles Tate Regan dissected a smaller, attached fish on a female and discovered they were neither growths nor offspring, but the female’s mate! 

Male anglerfish are substantially smaller than females, only about one inch long, and lack lures, large maws, and the frightening teeth of their female counterparts. Since males are not equipped for survival on their own, they spend their lives seeking out a female mate— and mate they do. Male anglerfish have small hook teeth that they use to latch onto a female’s body. Once attached, the male anglerfish releases an enzyme that dissolves the membranes of his mouth and her skin so that their bodies can fuse together, blood vessels and all! The male will lose the body parts no longer necessary to him, including eyes, fins, and sometimes even his own internal organs. He is then entirely dependent on the female for nutrition and survival and essentially becomes a fleshy lump, ready to release sperm into the water when his mate chooses to release eggs for fertilization. Even more fascinating, a female can carry up to six males at one time!

Not every species of male anglerfish is destined to such a dark fate, but this seemingly parasitic form of reproduction sure does sound like the stuff of science fiction. So, if you’re ever feeling down in the dumps about your love life, just remember: at least you’re not an anglerfish! 

Your Neighborhood Gecko

Olivia G. Schweikart3 Comments

Because of their solo nature, it’s not likely to spot a group of geckos in the wild. However, one species of gecko has adapted to a more urban lifestyle: the Mediterranean Gecko. Better known as the Common House Gecko, these creatures originated between the Northern parts of Africa and Southern Europe.

gecko-2656812_1280

First introduced to other warm countries, the Mediterranean Gecko made its way to Florida and has been leaving a trail ever since. If you live in an urbanized part of the Southeastern United States, there’s a good chance you have a few house guests.

Don’t be alarmed yet, though. These lizards are ferocious insect hunters and are great for keeping down the insect population outside your home. The best way to spot them is at night on a lit porch where insects tend to collect, however on occasion, you may be able to see some wandering about throughout the day.  These geckos tend to be skittish and are likely to run from human presence, but if you happen to get close to one, their docile nature presents no cause for danger.

While there is a wide range of color morphs for Mediterranean Geckos, a few identifying characteristics remain the same. If you feel you have a few new outdoor companions, the identification guide below might prove useful:

Screen Shot 2018-06-19 at 4.48.59 PM

If you answered yes to all of these questions, then you’ve got yourself a fierce home defender! They may not be the best at insuring your cars, but they will definitely give bugs a run for their money.