You'e probably come across the terms 'microevolution' and 'macroevolution'. 'Microevolution' is generally taken to mean small-scale changes in a population's gene pool, while 'macroevolution' is evolutionary change at the level of species, or genus, or phylum. This distinction can cause problems with understanding…
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Sexual signals and strong, silent males
On hot summer nights male crickets chirp constantly in their attempts to attract mates, rubbing a toothed ‘file' on one forewing over a ridge on the other forewing to produce their song. But this can be a risky business, as it might not be only females who are drawn by the males' calls. Predators and […]
Continue reading“Punk eek” and speciation
The concept of punctuated evolution – bursts of evolutionary novelty separated by long periods of stasis – was first proposed by Stephen Jay Gould & Niles Eldredge in 1972. Since then, there's been an ongoing debate among evolutionary biologists about how significant ‘punk eek' could be in the evolution of new species. (Remember that they aren't […]
Continue readingCharles Darwin, I presume?
As I was reading the Saturday morning paper, a full-page ad caught my eye. Auckland War Memorial Museum is hosting an exhibition on Charles Darwin, and it opens on September 29. Yep, I'll be going!
Continue readingThe nature of natural selection
If you've gone through the Schol Bio exam papers from previous years, you'll have noticed that evolution is one of the key themes in every paper. So I thought it could be useful to spend a bit of time on concepts relating to natural selection, one of the drivers of evolutionary change.
Continue readingThe improbability of an eye… (‘intelligent design’ part 2)
The camera-type eye of humans (& in fact all vertebrates) is often held up as a classic example of what ‘intelligent design’ (ID) proponents call irreducible complexity. The argument goes like this: a) the camera-type eye needs all its parts to function. b) It couldn’t possibly be assembled randomly as Darwinian theory claims. c) The […]
Continue reading“intelligent design” – science or philosophy?
At my scholarship preparation day yesterday I was asked if students could expect an exam question about evolution and intelligent design. My answer? No, because "intelligent design" is not a scientific explanation for the diversity of life on earth. My reasons for saying this? Read on…
Continue readingThe risks of sex (well, one of them, anyway)
That got your attention, didn't it? Being male can be a risky business. In a butterfly called Hypolimna bolina, there's a rather nifty bacterial parasite called Wolbachia that has unfortunate effects on male butterflies. It's carried down the maternal line and kills off male embryos. Just the males. This can result in some pretty skewed sex ratios. (And presumably an […]
Continue readingExtending our family tree?
You may have read the recent press coverage about the discovery of Homo erectus and habilis remains that suggest that these species coexisted for much longer than scientists had previously thought. The coverage was accompanied by headlines implying that the new finds overturned our current understanding of human evolution. But just how accurate is this?
Continue readingAncient data + modern technology = enhanced understanding
One of the attributes of a successful student is the ability to integrate material from across the curriculum – pulling together knowledge from (say) genetics, evolution, and biotechnology into a coherent whole. Here’s an example of a recent paper that integrates biotechnology techniques and genetics to clarify our understanding of our own evolutionary past.
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