It’s a Wonderful World: Lake Malawi Cichlids

As a family, cichlids are not especially noteworthy. Cichlids are “perch-like” bony fish found all over the world and are most diverse in South America and Africa. Familiar names in the cichlid family include popular aquarium fish such as the angelfish or the discus. Cichlids such as tilapia are also commonly found in the seafood department.

Not so interesting, right?

The Habitat
A more interesting story looks at a subset of the cichlid family, the Lake Malawi cichlids. Lake Malawi is a geologically young lake in the Great Rift Valley of East Africa. Since it hasn’t been around for millions upon millions of years, it’s an amazing example of species colonization and adaptive radiation.

Whenever a new habitat forms, whether it be a volcanic island (like Hawaii!) or the formation of a lake (like Lake Malawi), it is initially barren of life. This is new real estate! But over time, species from neighbouring habitats will, by chance, colonize it. Plants may get blown in, or an errant current may disperse a school of fish, for example.

The Genetics
Due to variation in our genes, no two individuals are the same. By nature, living things tend to have preferences – some tolerate cold temperatures better, while others need more light, for example. Having preferences can be beneficial, ecologically speaking, because it prevents competition between members of a species for the same habitat. And over a LONG time, these preferences can lead to differential mating. For example, if some members of a species preferred brackish water and spent the majority of their time in brackish water, these members are more likely to mate with each other rather than someone on the other side of the lake. This is probability. And finally, over a long LONG time, genetic differences may accumulate due to this preferential mating. And so you have it – from adaptation to different environmental niches, a colonizing species can radiate into many different species, each one specialized to exploit a certain niche.

The Fish
The Lake Malawi cichlids are an amazing example of this process. Species of Lake Malawi cichlids can be readily divided into groups: an open-water, sand-swelling group and a rock-dwelling group. Within these two general types, hundreds of species – each slightly different from the other – have been defined. Many more are thought to be still be undiscovered!

And, it isn’t over. Estimates have placed the origin of the Lake Malawi cichlid diversification at 10,000 years ago, or less. On a geological scale, this is nothing. Genetically, this means that there is not yet a great deal of difference between different cichlid species. As such, many different cichlid species are still able to hybridize with each other where niches overlap or when placed in a laboratory setting. Aquarists take advantage of this, for example, to breed fish with different colours and patterns.

This pattern of colonization and subsequent radiation is found repeated in many other species and habitats. Check out a few other famous examples in the silverswords of Hawaii or the finches of Galapagos!

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Tracking puffins

Puffins are small seabirds which breed in coastal colonies in the North Pacific and North Atlantic oceans.  Their numbers have been declining for about half a century, partially due to invasive plant species which are taking over breeding grounds.

Their migratory patterns are currently being studied using geolocator tags by a group from the Centre for Ecology and Hydrology and is featured in this recent BBC article.

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Success and genetics

In this age of ubiquitous genetic data and ease of sequencing, the unraveling of genetic determinism continues to be a popular aspect of research. The ability to say that possession of Gene X or Mutation Y leads to Disease A or Behavior B is powerful and wide-ranging in scope, and appeals to many who seek to understand life.

Indeed, many human behaviors and conditions have already been linked to certain gene variants. Mutant forms of the BRCA gene have been widely publicized as indicators of breast cancer susceptibility. Another example includes the SERT gene, for which a certain variation increases a person’s susceptibility to serious depression.

Of course, it is widely accepted that genetic (or biological) determinism is not the only determinant of human phenotype – environmental (or social) determinism plays a role as well. However, it is still common and accepted to see studies which support the idea that a certain gene will “increase risk” for a certain disease or behavior. Thus, if one possessed a “bad gene” and was exposed to a “bad environment”, the outcome would likely be negative.

But what happens if you have a “bad” gene but had a “good” environment? Or even, some sort of “ideal” environment?

An article in The Atlantic, published late last year by David Dobbs, highlighted a non-human primate facility in the United States which studies genetics, behavior, and the so-called “orchid hypothesis”. Researchers found that these “bad genes” are perhaps more accurately classified as “genes for potential”. Researchers found that, given the right environment, individuals possessing these genes could excel far beyond the capabilities of a “normal” individual. In the primate facility, this was illustrated by the ability of one family of primates to completely take over dominance of the colony after years of being submissive to another family. This was made possible by a change in the social and environmental conditions.

A similar result was seen in a study of children’s behaviour. This study put mothers and children through a program designed to foster good social behaviour in young children by encouraging positive interactions between mother and child. The authors found while all of the children improved, the children who had an ADHD “risk” allele improved the most, and indeed, did better than their “normal” counterparts.

So what could this mean for other aspects of human health? For example, do autistic children have the potential for greatness that a normal children lack? We’ve all heard of autistic piano or math prodigies. These studies suggest that we might find ways for all autistic children to excel. And if so, how do we find the right environment to foster this behaviour?

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Taxidermy 101

When I was an undergrad I volunteered the natural history museum on campus.  Now at the time, calling it a museum was a bit of a stretch.  It was an amazing collection of specimens, no one would deny that, but they were all housed in locked cupboards in the recesses of the old biology building.  Worse, they were not even housed on the same floor or even the same wing.  There were fish specimens in the basement, birds and bugs on the top floor… No one knew about them!

I was introduced to the museum during a class on biodiversity, from Dr. Wayne Maddison.  He introduced the class to Dr. Rex Kenner, who ran the vertebrate museum.  Rex showed the class examples of endangered species, extinct species, beautiful animal pelts, exotic insects… It only took one visit to the museum, and I signed up to be a volunteer.

To be accurate, UBC has more than one natural history museum collection – there’s a vertebrate collection, a bug collection, a fossil collection… and so on and so forth.  Rex was in charge of the vertebrate collection.  He was a bit of a bird hobbyist, so my role in the museum was to help prepare bird specimens.  Taxidermy!

From Rex, I learned how to take a dead, bird – usually one who met an unfortunate fate, like flying into a window – and create a specimen which could be used indefinitely for research and for teaching.  Until I became a volunteer, I had no idea that museum archives could be used for research.  But over the course of my time in the museum, I would often see grad students taking measurements, photos, and sometimes samples.

Taxidermy isn’t for the faint of heart, certainly, and I won’t go into the details here.  But I was fortunate enough to work with many beautiful species of birds – everything from Stellar’s Jays to owls to little thrushes.  I was able to hold in my hand a representation of so many species which I never would have seen up close.  Without the museum, I never would have been able to pull back the wing to see the iridescence feathers, nor examined an owl to find it’s “ears”.  And, thanks to the museum, other students and researchers will be able to see, hold and use these specimens as part of their studies and research.

Most exciting is the upcoming public opening of the new Beaty Biodiversity Museum which will finally house these collections!  Gone are the dusty corridors of the old biology building – they are demolishing it even now.

It will be a bittersweet event for me.  For several weeks now, I had planned to visit Rex and extend my congratulations on the move to the new museum.  But I kept putting it off, thinking that I would have all the time in the world.  I received an email a few days ago from his assistant.  Dr. Rex Kenner passed away the previous weekend, only weeks before the museum would have opened to the public.

I’d like to thank him, even if it is a bit late, for all his hard work and dedication to maintaining and promoting the collections.

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