Because it’s worth repeating

A creationist in one of the comment sections recently repeated this old canard.

the dictionary says (among other things) that a theory is:
1. contemplation or speculation.
2. guess or conjecture.

there i go? again?
you just seem pretty intent on disparaging arguments but not refuting them.

This is yet another point where atheists and other non-deluded people are willing to be honest, all the while watching creationists do just the opposite. It’s like it’s just so damn inconvenient to come to a straight-forward, truthful understanding of basic concepts for the religious that lying has become okay for them; the ends justify the means.

So it is worthwhile to repeat, for the nth time, just what a theory is and is not.

Insofar as my theory that ice cream is great can be considered a theory, yes, creationism is a theory. But it is not in any way a scientific theory. The requirements to reach this high level are rigorous. For starters, what predictions does creationism make? What experiments can be carried out to falsify the hypothesis? Can others repeat these experiments? Are there other plausible explanations? Are there better explanations?

The word “theory”, as any educated, honest person knows, carries far more weight in science than it does for the lay public. In truth, the word gets mixed up in casual talk within science, even sometimes becoming conflated with “hypothesis”, but no one really blinks because the context allows for the use of shorthand. Think to Richard Dawkins’ style of writing. He uses personification all the time, especially when discussing natural selection. He will start out with qualifiers and scare quotes – “Natural selection ‘wants’ to weed out the bad genes” – but as he goes on, the reader comes to an understanding of the fact that the good doctor is bringing evolutionary biology to life via a particular way of writing. It becomes obvious that it is inappropriate to apply anthropomorphic qualities to what Dawkins is describing – and it is context that allows for this.

But in public forums or political circles, there can be no assumed knowledge of science and what its terms mean; it is a danger to allow for the use of loose language without qualification. That is why it is so important to distinguish between the lay definition of “theory” versus its scientific definition. In science it references something which has evidence, has been tested, has journal papers all about it, and usually there is a high degree of consensus. The Big Bang, evolution, global warming, plate tectonics – these are all theories. Creationists have no theories. They have no evidence, no reason, no logic, no testing, no raw data, no way to interpret any sort of observation in a way that holds any scientific significance.

Tetrapods pushed back 18 million years

The oldest tracks of four-legged animals have been discovered in Poland.

Rocks from a disused quarry record the “footprints” of unknown creatures that lived about 397 million years ago.

Scientists tell the journal Nature that the fossil trackways even retain the impressions left by the “toes” on the animals’ feet.

The team says the find means that land vertebrates appeared millions of years earlier than previously supposed.

This is especially interesting because Tiktaalik was discovered by Neil Shubin based upon a lack of land animals 390 million years ago but a prevalence 360 million years ago. He specifically looked for a place likely to have fossils that was 375 million years old in order to discover his transitional fossil. This new information doesn’t mean that he just got lucky – one would still expect to find transitional forms prior to true land animals – but a little luck was involved. (It was actually involved no matter what he wanted to find and when he wanted to find it because fossilization is so rare anyway.)

One important fact to note about Tiktaalik is that it likely lived in freshwater. This is key because a marine environment is less conducive to a full move onto land than a freshwater lake or river, and Tiktaalik shows evidence that it is closely related to later fully land animals. Think about it for a moment and it becomes obvious: you need to be able to drink freshwater, not salt water, in order to fully utilize the land. If your ancestors lived in freshwater, then the first transition has been made for you. That means the owners of these newly discovered footprints represent a transition of sorts, but they were still very much tied to a marine life, unlike Shubin’s discovery.

Devil cancer update

The devastating cancer spreading through the Tasmanian devil population has so far met resistance in at least one devil (Cedric), and possibly in his brother (Clinky).

Both were injected with dead tumours by scientists. Clinky produced no antibodies, but Cedric did and appears to have built-in defences against the mystery illness.

The experiments have now moved up a gear.

Researcher Alex Kriess says the pair have had live cancer cells inserted into their faces.

“They haven’t developed a tumour so far,” he said. “We injected very few cells so it might take a while until they develop anything that we can see.”

The next step is to see why Cedric may be resistant to the disease, which Jerry Coyne has deemed “can be regarded as a separate organism, genetically free to undergo independent evolution.” (The syntax is correct, but for clarity, it’s the disease that can be regarded as a separate organism.)

The most interesting aspect of all this is that Cedric comes from the side of the island not yet especially devastated by the disease. As more research is done, it will be interesting to find out if there is any sort of special history with cancer, even this specific cancer, that Cedric’s part of the island has had. That could be one driving cause behind the genetic difference to consider in addition to simple drift or geographical barriers.

Image via Jerry Coyne

Water on the Moon

NASA discovered there is plenty of water on the moon.

Experts have long suspected there was water on the moon. So the thrilling discovery announced Friday sent a ripple of hope for a future astronaut outpost in a place that has always seemed barren and inhospitable.

“We found water. And we didn’t find just a little bit. We found a significant amount,” Anthony Colaprete, lead scientist for the mission, told reporters as he held up a white water bucket for emphasis.

He said the 25 gallons of water the lunar crash kicked up was only what scientists could see from the plumes of the impact.

This is equivalent to roughly a bathtub’s worth of water from this double-impact.

One part of me wants to endlessly speculate at the possibility of microbial life. But all reason and rationality tell me to be cautious. Water does not automatically mean life (especially when its frozen).

…but what if it does mean life, at least in this case? Would the world realize the utter significance of this discovery? Not since Darwin described evolution by natural selection has there been such an important find.

Old eggs, daphnia, and evolution

When predation is high, crustaceans and other water loving egg lay-ers are not hatched much. What often happens is that they will remain dormant until later in the year when the predators are much less active. This offers a great research opportunity into evolution.

By hatching these eggs, Hairston and others can compare time-suspended hatchlings with their more contemporary counterparts to better understand how a species may have evolved…

What happens is that some of these eggs can remain unhatched for years and years, not just seasons. This is the case with daphnia. These are normally seasonal crustaceans, but researchers have specimens which are upwards of 40 years old. They use these to compare the change which has happened to this species over time. Daphnia_DGC

In the 1960’s, the lake from which these daphnia were taken had non-toxic levels of algae. But in the 1970’s, pollution had caused the algae to raise to a deadly imbalance. Currently, daphnia still reside in the lake, but researchers have found they are markedly different from the eggs they hatched. The older version of the species was unable to survive in the lake, poisoned by the overwhelming cyanobacteria. Clearly, the newer species had adapted to their new environment throughout the 70’s and subsequent decades.

More interesting fossils than Ida

Ida is a new fossil discovery that has been horribly over-hyped. It is being called “the missing link”. Following sentences usually mention humans. In other words, some articles are crafty and don’t directly say this fossil is important to Homo sapiens. Others are less crafty. All of this non-sense plays right into the hands of the lying creationists (sorry to be redundant).

Darwinius masillae, otherwise known as Ida, is a tremendously well-preserved fossil that is a primate ancestor. As with most fossils, it was probably a relatively close cousin of one of our direct ancestors. (Note, “relatively close”. Of course, all fossils we find are eventually cousins of our ancestors, if they aren’t directly our ancestors.) How close is difficult to tell – forget saying it’s a direct ancestor. It is a member of the same suborder as humans (and apes and monkeys), haplorhine, but that doesn’t mean Ida wasn’t the last member of her particular population. It can tell us some interesting things, but it in no way independently confirms evolution. Science doesn’t work that way; theories are supported by a wide body of evidence. A single find can add a little weight to a theory, but doesn’t usually completely make a theory. (Notable, if this were found in the, say, Jurassic period, it would have been a find that actually spun evolution on its head – find me a part of creationism [or its coy, dishonest, lying cousin intelligent design] that can be falsified.)

So while interesting and not simply trivial, there are more important fossils out there than Ida. What’s more, there are more interesting fossils. (Guess which claim is the author’s opinion.) Here are some.

Lucy

Lucy

Maiacetus inuus

Maiacetus inuus

Schinderhannes bartelsi

Schinderhannes bartelsi

Tiktaalik

Tiktaalik

Only in the light of evolution

Now that finals are over, I can devote more time to my dear, neglected blog. I begin with a series:

I am following a specific chapter in Jerry Coyne’s Why Evolution is True.

The fossil record: We should see fossils in a certain order if evolution is correct. They should go from simple to more complex overall, and the fossils we see in the most recent strata should resemble extant life much more than the fossils we see in old strata.

We should also see changes within lineages. We should be able to observe instances of gradual change in species that eventually leads up to either current species or at least to the time of extinction for these species.

Here’s a simple timeline of life’s history. Click it.

What the evidence shows is gradual change. First we find simple bacteria which survived off energy from the Sun, then we see more complicated cells known as eukaryotes arise. (You are a eukaryote.) Next we see a slew of multi-cellular animals arise. They’re still simple, but much more complex than the original bacteria. A few million years later more complicated life arrives. Early (and simple) plants begin to take hold. Soon the fossil record begins to show more plant complexity with low-lying shrub such as ferns, then conifers, then deciduous trees, and finally flowering plants. Gradual changes occur in the oceans and fresh waters which lead to fish and then tetrapods (Tiktaalik comes to mind).

One of my favorite fossils is trilobites. They’re extremely common due to their hard bodies. In fact, even their eyes are well-preserved because of their hard mineral make-up. I personally recall entering touristy-stores seeing countless fossils of these guys in the mid-west to the west (which, unsurprisingly, was once a shallow sea). This image shows the different lineages of this organism. Studies show that the ‘rib’ count has changed over time in each individual species, often without regard to how the other species changed. Going back further, there is less and less divergence in each species. Eventually, as evolution predicts, they all meet at a common ancestor.

So naturally the next step is to find fossils which show more significant changes. Let’s take birds and reptiles. They hold similarities between each other, both morphologically (certain shapes and structures) and phylogenetically (genetic sequence). A good hypothesis is that they came from one common ancestor. If this is true, the links between birds and its ancestors and reptiles and its ancestors should lead to the same point. They do. Dinosaurs are the ancestors of both. The links between birds and dinosaurs are so incredibly well established that I’d prefer to not go over them in detail. But for starters, some dinosaurs sported feathers and claws and had the same proteins for the feather-making process as extant birds. The links between reptiles and dinosaurs is easier just on intuition, so I’ll leave it at that for now.

Other transitional fossils include the already mentioned Tiktaalik. A view of the history of life can be see here. This shows the change in head and neck structure. Recent research on long-ago discovered Tiktaalik fossils has shown the importance in the gradual bone changes in the neck. These changes – a hallmark of evolution – were important to the ability to turn its head. This is a hallmark because natural selection only modifies what already exists. This is precisely what happened.

Going further with this example, evolution makes predictions as to how early fish evolved to survive on land. If there were lobe-finned fish 390 million years ago and obviously terrestrial organisms 360 million years ago (which is what the fossil record shows), then if scientists are to find transitional fossils, they should date in between that time frame. There should be an animal that shows both features of lobe-finned fish and terrestrial animals. Tiktaalik is that animal. It has fins, scales, and gills, but it also has a flat, salamander-like head with nostrils on top of its nose. This is a good indication that it could breathe air. Its eyes were also placed there, indicating that it swam in shallow waters. Furthermore, it was lobe-finned, but shows bones (which eventually evolved into the arm bones you used to get out of bed today) that were able to support its weight to prop itself up. And of course, it dates to 375 million years ago.

Next, evolution says the fossil record should show recent fossils being more closely related to extant species than are early fossils. This is precisely what happens. Sixty million years ago there were no whales. Fossils resembling modern whales only show up 30 million years ago. So, again, evolution makes a predication: if transitional fossils are to be found, they will be within this gap. And so it is.

We begin with Indohyus. It was an artiodactyl. This is important because extant whales have vestigial bones which indicate that they came from this order: scientists expected to find this because, again, evolution predicted it. It should be of no surprise that this fossil dates to about 48 million years ago, right in the predicted gap. From here there is a gradual evolution shown in the fossil record which leads up to modern whales.