Darwinism Evolution extinction Intelligent Design

A new bug for Darwin’s finches: Mating disrupted by parasite

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Remember how Darwin’s finches proved Darwinism – and then the story collapsed in a heap of uncertainty about how different all those “new species” were/are?

Invasive parasites in the Galápagos Islands may leave some Darwin’s tree finches singing the blues.

c The nonnative Philornis downsi fly infests the birds’ nests and lays its eggs there. Fly larvae feast on the chicks’ blood and tissue, producing festering wounds and killing over half of the baby birds. Among survivors, larval damage to the birds’ beaks may mess with the birds’ songs when they’re older, possibly affecting their appeal to potential mates, researchers report June 12 in Proceedings of the Royal Society B. …

For medium tree finches, the deformity meant they sounded similar to a small tree finch with a healthy beak. That may explain why scientists had previously had observed female medium tree finches choosing small male tree finches as partners, instead of males from their own species. The researchers did not observe female small tree finches choosing medium tree finch mates.

Carolyn Wilke, “Parasites ruin some finches’ songs by chewing through the birds’ beaks” at ScienceNews

One evolutionary biologist predicts the “extinction” of the medium tree finch as a result. The insect is thought to have arrived in the Galapagos in about 1960.

The whole story leaves one wondering what role incidental factors played, over many centuries, in the constant, reversible micro-evolution of the once-iconic Darwin’s finches.

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See also: Epigenetics may explain how Darwin’s finches respond to environment

5 Replies to “A new bug for Darwin’s finches: Mating disrupted by parasite

  1. 1
    OLV says:

    Protein concentration gradients pattern developing organisms and single cells.

    Pom1 kinase forms gradients with maxima at cell poles. Pom1 controls the timing of mitotic entry by inhibiting Cdr2, which forms stable membrane-associated nodes at mid-cell. Pom1 gradients rely on membrane association regulated by a phosphorylation-dephosphorylation cycle and lateral diffusion modulated by clustering.

    the gradients modulate Pom1 mid-cell levels according to cell size.

    All organisms need to know how to arrange different cell types during the development of their organs and tissues. This information is provided by protein concentration patterns, or gradients, that tell cells how to behave based on where they are positioned. The same fundamental principles also work on a smaller scale.

    The role of clusters in creating gradients is not only relevant for yeast cell division. It could potentially apply to the gradients that organize cells and tissues in different organisms. Future work could examine whether similar principles apply in more complex systems.

    In many organisms and cell types, graded protein patterns provide positional information.

    Although mechanisms of gradient formation vary, in all systems the graded patterns are thought to convey information at a distance from the source.

    cells likely have secondary sizer mechanisms, perhaps monitoring different geometrical quantities

    Multi-phosphorylation reaction and clustering tune Pom1 gradient mid-cell levels according to cell size

    eLife. 2019; 8: e45983.
    doi: 10.7554/eLife.45983

    Veneta Gerganova,1 Charlotte Floderer,2 Anna Archetti,2 Laetitia Michon,1 Lina Carlini,2 Thais Reichler,1 Suliana Manley,2 and Sophie G Martin1

  2. 2
    OLV says:

    The term “Control systems” seems mentioned in this paper a few times. Isn’t that a specialty in electrical engineering?
    Are they implying that we find that kind of stuff in biology?
    Really? Are they kidding?

    Control of cell size requires molecular size sensors that are coupled to the cell cycle.

    Pom1-Cdr2-Wee1 operates in multiprotein clusters at the cortex to promote mitotic entry at a cell size that can be modified by nutrient availability.

    Many cell types display a remarkable ability to maintain a constant size during rapid cycles of growth and division

    Such cell size control is a system-level property that emerges from the integration of multiple size-dependent signal transduction pathways. Each signaling pathway is comprised of tunable biochemical parameters, including gene-expression and post-translational modifications such as protein phosphorylation

    One major challenge in cell size research is to understand the biochemical mechanisms of signal transduction in each pathway, and what makes them size-dependent.

    These control systems can generate size homogeneity for a given cell type, but cell size is also an adaptable property.

    Thus, a second major challenge in cell size research is to understand how size-dependent signaling pathways respond to changes in cell metabolism and stress.

    Our findings suggest a new model for gradient formation, which is distinct from this previous model in four ways.

    further investigation of these lipids and their localization dynamics could reveal additional layers of this morphogen-like gradient.

    Identification of additional growth and environmental conditions that alter the relative distributions of Pom1 clusters and Cdr2 nodes, and determination of how they connect with other cell cycle signaling pathways, may reveal new mechanisms for nutrient modulation of cell size control.

    The existence of sizing mechanisms that measure other aspects of cell size, and function independently of the Pom1-Cdr2 surface area sensing network, underscores that cell size is a system level property controlled by multiple signaling pathways. Thus, it remains important to discover size-dependent signaling mechanisms within each individual pathway, as a step towards understanding the integration of multiple pathways into a larger size control system.

    Stable Pom1 clusters form a glucose-modulated concentration gradient that regulates mitotic entry

    Corey A H Allard, Hannah E Opalko, and James B Moseley
    eLife. 2019; 8: e46003.
    doi: 10.7554/eLife.46003

  3. 3
    OLV says:

    Individual cell types have characteristic sizes, suggesting that size sensing mechanisms may coordinate transcription, translation, and metabolism with cell growth rates.

    size sensing in animal cells combines both titration and spatial sensing elements in a dynamic mechanism whereby microtubule motor-dependent localization of RNA encoding importin ?1 and mTOR, coupled with regulated local protein synthesis, enable cytoskeleton length sensing for cell growth regulation.

    Cell size sensing—a one-dimensional solution for a three-dimensional problem?
    Ida Rishal and Mike Fainzilber
    BMC Biol. 2019; 17: 36.
    doi: 10.1186/s12915-019-0655-3

  4. 4
    OLV says:

    Forget the finches.

    Any idea how we got all that functional complexity of the complex functionality in the biological systems?

  5. 5
    OLV says:

    Neo-Darwinism is under attack from its former allies that have defected and now look for naturalistic alternatives under the title “the third way of evolution”


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