Saturday, August 30, 2008

Photohunter: Beautiful

I thought I'd put up a classic beauty. This guy, like many other males in the animal kingdom, has resorted to flashy, bright, and beautiful colors to attract the females. So the question is, why? Females put a lot of effort into reproduction; eggs are more energetically costly to make than sperm, not to mention the costs of rearing the chick after it is laid. Females typically (at least on land) mate fewer times than males, and with fewer individuals. Because of that, females are super choosy about who they do mate with, often wanting to make sure that they are getting the 'best genes' for their offspring.

Their choosiness often results in visual signals of a male's health and well being. In this case, by growing a long tail, they show they can gather enough food to grow such a tail and are still strong or fast enough to escape predators. The size of the eyespots on the tail has been linked with size of the bird as a hatchling. So picking guys with bigger eyespots may give the female bigger chicks. Bright plumage means that the bird does not have any parasites, this may mean that the male has some nice anti-parasite genes to pass on, or at the very least, that the female won't get any parasites while mating with him.

In short, this beautiful eye-candy is meant to show the females that they are quality picks.

Friday, August 29, 2008

Life Photo Meme: Wild Welwitschia

Kingdom: Plantae

'Phylum: Gymnospermae' (not technically a phylum, but a useful taxonomic grouping)

Class: Gnetopsida

Order: Welwitschiales

Family: Welwitschiaceae

This is an absolutely wild plant, that I would not mind seeing in the wild. This is Welwitschia mirabilis, a plant native to the 'fog belt' of the Namib desert in Africa. It is a gymnosperm, a group of plants which bear cones instead of flowers for reproduction (like cycads and pine trees), and is the only gymnosperm to have adapted to desert life. However, the male cones (male and female cones are located on different plants) have structures which resemble those found in a flower.

They are also super unusual in the way they grow. Most plants have an apical meristem which allows them to grow upwards. In Welwitschia, the apical meristem dies shortly after germination, leaving them only able to grow outward, and upwards a bit at the edges of the trunk. Think of a tree trunk that's been lopped off close to the ground, and hollowed out in the center like a bowl, and you have the basic shape of a Welwitschia trunk.

Finally, their leaves are the most unique in the plant kingdom. They are the only plant to posses permanent leaves. Most plants grow leaves from outgrowths of the apical meristem, these dividing cells bud off to form leaves at the tips of branches, or at certain nodes along the branch. Welwitschia possesses only two leaves which grow from the sides of the trunk shortly after germination. These two strap-shaped leaves continue to grow for the rest of the plants life, from the base of the leaf. The leaves also posses many grooves and blind ends, as well as stomata along the top of the leaf, which allows the plant to collect water from the morning fog.

Welwitschias live for 500-600 years.

Sunday, August 24, 2008

Playing dead

Just read a neat paper on the heritability of death feigning and how it may be selected for in the wild by Miyatake et al. (2004). Death feigning is when a creature pretends to be dead, either by falling off a twig and curling up its legs, or by freezing, presumably to escape predation. The gray death-feigning beetle pictured above can feign death for up to thirty minutes (according to the beetle dealer). What Miyatake and the others wanted to know was, is this death-feigning ability heritable, and does it actually help them escape predation?

So they took 200 red flour beetles and recorded how long they played dead for after touching them with a stick. The 10 males and 10 females who feigned death the longest were used to start a long line, and the 10 males and 10 females who feigned death the shortest were used to start a short line. They then repeated this procedure for ten generations, allowing only the 20 longest feigners and 20 shortest feigners to reproduce each generation.

After ten generations, they found that the long line feigned death for a longer period of time than the short line did. The long line feigned death for over a minute and a half, while the short line only feigned death for about 5 seconds. They also found a difference in the numbers of individuals who actually feigned death. What they saw was 86% of the long-line individuals feigned death, while only 7% of the short-line individuals feigned death.

So now they know that death feigning is heritable and can be selected for or against in nature, but does it actually work to help save them from predators? Will it actually be selected in nature? To find this out, they introduced a predator and recorded survivorship and behaviors of short-line and long-line individuals. What they found was that the jumper spider used as a predator would lose interest in the beetle if it feigned death. So most of the long-line individuals survived (64%), and most of the short-line beetles were eaten (73%).

So if the beetles have predators in an area that act like the jumper spider, you could expect that the beetles in those areas would have long death-feigning times, but in other areas without such predators, you may expect shorter feigning times. Now all you have to do is go out and test that!

Saturday, August 23, 2008

Photohunter: Wrinkled Frogfish

This is one of my favorite fishes, the frogfish. They are related to the anglerfishes and have a lure to entice little fishes, like true anglers. Unlike the other anglers these guys are found in deeper waters hanging out on reefs, but not as deep as the true anglers who are also pelagic. Also, they are not ones for swimming. Their fins have an elbow-like joint which allows them to climb on the reefs. Apparently, they can jet-propel themselves by sucking in water and pushing it out the small gill opening behind the second set of fins [1]. They can glide for a good distance before settling on the reef.

They are ambush predators, lurking on the reef looking like a lumpy rock or sponge. An unwary fish may settle next to them, or be attracted by the small waving lure... then snap. The frogfish can expand its mouth and guts to a considerable degree and swallow fish almost as large as itself [1,2].

Thursday, August 21, 2008

Life Photo Meme: Smart Slug

Kingdom: Animalia

Phylum: Mollusca

Class: Gastropoda

Order: Nudibranchia

Family: Facelinidea

This is the nudibrach Hermissenda crassicornis. While it may not look like much, when I look at it, I think 'smart'. H. crassicornis has often been used as a model animal as it is a great thing to study if you want to learn how memories are formed. They have a very simple nervous system, simplified to the point where every neuron has been mapped and named. Additionally, they can be conditioned to respond in certain ways when presented with a stimulus (much like Pavolv's dogs). Put that together with the ability to follow impulse along the nervous system, and you can 'see' how the slug reacts normally to a stimulus, then see how the route changes after you condition them. They've actually found out where memories are stored in these guys! If you want to learn more about learning check out Blackwell, 2006 for a review on the subject.

Saturday, August 16, 2008

Photohunter: Colorful Cucumber

This is a violet sea cucumber (also called a sea apple). They are native to the western pacific and eastern indian oceans. They get their name from the violet ring around their feeding tentacles. Their body may be violet as well (like this guy's) or may be yellow, red, or blue. They use their bright yellow tube feet to move around the ocean floor, and the feeding tentacles to pick up detritus from the sea floor, or filter it from the water column.

The color of the violet sea cucumber is not just for show. When disturbed, like being picked on by a fish, the violet sea cucumber release toxic mucus. Fish and other animals learn quickly not to upset anything that looks like them.

Thursday, August 14, 2008

Garibaldi: free from harassment, free to harass

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii (ray-finned fishes)

Order: Perciformes (perch-like)

Family: Pomacentridae (Damselfishes)

This is the garibaldi (Hypsypops rubicundus), one of the few damselfishes which are found in central Californian waters. It ranges from Monterey to southern Baja. It can be easily distinguished from the other damselfishes by its bright orange color. The garibaldi is the Californian marine state fish, and as such it is a protected species. It is illegal to capture these guys, so they are generally free from human harassment.

On the other hand, this fish is reputed to be rather territorial, willing to chase away any other fish (including other garibaldis) from its area, except during the breeding season. The males make and maintain a nest filled with red algae, and the females visit the nests sites to evaluate which are the best. Females will lay their eggs in the nest of their choice, and the males will take care of them until they hatch. When the young garibaldi settle out of the plankton, they posses bright blue spots. Reportedly, these spots help to protect them from harassment from the adult garibaldis (Love, 1996).

Monday, August 11, 2008

Review: Page Museum

The Page Museum, also known as the La Brea Tarpits, is located in north-west of LA city proper. This is a medium-sized museum that is dedicated entirely to ice age animals, particularly those found in the California area. You won't find any dinosaurs here, but you will find some amazing creatures, such as dire wolves, mammoths, mastodons, condors, and big cats (to name a few).

Dire Wolf


Giant Sloth

The cool thing about this museum, apart from the focus on ice age animals from the area, is that most of the creatures featured were found on the grounds of the museum. The page is the site of several very active tar pits (which makes walking on the grass a somewhat risky proposition). There is a lot of research going on, and the page makes use of that. They have a 'fishbowl' laboratory where you can watch paleontologists cataloging and restoring fossils, as well as sorting through the matrix (dirt or tar surrounding the primary fossil) for microfossils (bugs, small bits of bone, plant material etc.). During the summer, you might catch a glimpse of some researchers digging up fossils from pit 91. Right now at pit 91, they've stopped digging to work on the fossils they found in the basement of the near by art museum. So you can see the work in action.

Tar pit with fossils

In addition to the fossil displays, there are displays on the research being done, and two short films (one on the history of the museum and the other on the tar pits). There are curiosity carts for a more hands-on experience and two different tours (one for the inside of the museum and the other for the outside).

This is a great museum, a very rare opportunity to see ice age creatures from the very area they used to live. It's a great value too. $7.00 for adults, less for kids and students of all ages. I believe they also do discounted or free admission for members of other museums that are part of the ASTC system.

Saturday, August 9, 2008

Photohunter: Dark

Here's one of my favorite sunset pictures, the sun setting over the edge of the Australian outback, framed by a bottle tree. Bottle trees are named after the fact that the trunk looks like a bottle, and that it holds a lot of water. The insides of the trunk are very fibrous instead of being dense like most hardwood trees we know. Having all of these gaps inside of the trunk allows the tree to retain a lot of water, a fact exploited by the settlers and indigenous peoples of the drought stricken Australia.

It can get 18-20 meters in height and 2 meters in width (60 ft high and 6 ft across). It is also called Kurrajong, which is derived from the word 'fishing line' in one of the aboriginal dialects. The fibrous inner part of the bottle tree was often used to make twine products, such as fishing lines.

Here's a picture of a bottle tree in the day time:

Friday, August 8, 2008

Weekend work

This is particularly appropriate for my weekend... For more PhD fun, click link!

Thursday, August 7, 2008

Life Photo: Purple-ringed top snail

Kingdom: Animalia

Phylum: Mollusca

Class: Gastropoda

Order: Archaeogastropoda

Family: Trochidae

This is a purple-ringed top snail, Calliostoma annulatum, the most beautiful shelled snail on the west coast in my opinion. They cruise up and down kelp plants looking for a meal. Generally, they eat what ever is growing on the kelp plants, such as hydriods, bryozoans, diatoms, and copepods. If there is nothing on the kelp plant, they will eat the kelp itself. They have been known to travel 20-30 feet in a twenty-four hour period.

Sunday, August 3, 2008

Photohunter: clouds

This is a picture of a cloud of sperm. You can see the green anemone which produced these clouds wedged in between the upper rocks. Anemones are broad-cast spawners, which means that they release their eggs and sperm in the water column and hope that they get fertilized. They do try to coordinate their spawning efforts by using external cues, such as temperature. When the water gets warm enough, they release their gametes (eggs or sperm). However, for those living in the shallow tidepools, this can get a little tricky, as the temperature of the tidepool's water is often warmer than the ocean water. So, during the reproductive season, you can sometimes find anemones that were fooled into releasing their gametes early.