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The key point is that the first equation is describing frequencies, i.e., $\sum_{i=1}^n x_i = 1$, so there are only $n-1$ degrees of freedom. For instance, if $n=2$ (as in Hawk-Dove), you can totally describe the state of the system with just $x_1$, because $x_2$ is just $x_2=1-x_1$. This constraint is enforced by adjusting $\phi$. To convert the ...


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Forest Succession 101 Pines are actually fast-growing, shade-intolerant, early-successional species. When land is allowed to lay fallow after being cleared by fire, wind storms, human land use or other major disturbance, the successional sequence will begin. At first only herbs and grasses grow, but eventually these are shaded out by shrubs and tree ...


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It is assumed that this effect of locomotive behavior IS an effect on cognition (1-4). Navigation requires snapshot memory, learning, and attention (2-4). You asked if this effect of neonicotinoids on cognition manifests itself through other vital behaviors. The short answer, yes. Specifically neonicotinoids are shown to effect mating, queen behavior, and ...


3

According to the wikipedia page, a keystone species is: A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Thus, you could work out the keystone species in an ecosystem by sampling population size and and what size 'effect' the removal of the species from the ecosystem would have. ...


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You can find a discussion of this topic in the literature: Mitchell, Edward. 1970. Pigmentation pattern evolution in delphinid cetaceans: an essay in adaptive coloration. Canadian journal of Zoology 48(4): 717-740. Perrin, W.F., 1972. Color patterns of spinner porpoises (Stenella cf. S. longirostris) of the eastern Pacific and Hawaii, with comments on ...


0

The concept of a "climax community" has not been accepted as reality for more than 40-50 years. Frederic Clements was an early botanist examining succession in the first 20 years of the 20th century. It was Clements who developed the concept of the climax: he posited that the habitat and the populations acted upon one another in a reciprocal way until ...


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First, you cannot fully analyze pair-wise correlations between your environmental variables with NA values, and therefore cannot fully discount including covarying variables. If this is the case, you will not be able to know which of the covarying variables is responsible for any trends in your data. Second, I don't believe CCA will work with NA values -- ...


1

Dengler 2009 would be a good start. I'm sure this paper, his citations and papers citing Dengler's paper will get you well on your way.


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Theoretical ecology From wikipedia Theoretical ecology is the scientific discipline devoted to the study of ecological systems using theoretical methods such as simple conceptual models, mathematical models, computational simulations, and advanced data analysis. Effective models improve understanding of the natural world by revealing how the dynamics of ...


1

From what I know of ant-Acacia mutualisms, I've never heard of an ant gall in an Acacia. The link in your question also never mentions a gall. You've likely confused either domatia or Beltian bodies as a gall. Both differ greatly from galls in that domatia or Beltian bodies are created by the plant and not by the insect. Domatia are small plant-made ...


7

The behaviour that you describe is common in most animal species, as part of the natural trade-off between access to food, minimizing risk, habituation and hunger. Animals usually choose to forage in high-quality habitats that has a low risk of predation, but if food sources are depleted (or competition and/or territoriality is high) they will move to other ...


1

One of the comment to David's answer (which covers the history and reasons for spiderwebs in its two links) mentions a comparison between web patterns and molecular phylogeny. Not precisely that, but I found this article which opens up some interesting possibilities (I can delete this or turn it into a comment if you consider it too unrelated, please let me ...


4

Adding some additional database sources: -- Climate -- Prism The PRISM Climate Group gathers climate observations from a wide range of monitoring networks, applies sophisticated quality control measures, and develops spatial climate datasets to reveal short- and long-term climate patterns. WorldClim WorldClim is a set of global climate layers (climate ...


4

Why organisms reproduce If they didn't reproduce, they would die out. More concretely, suppose an animal is born with a mutation that removes the desire to reproduce. That animal will not have any offspring, so its genes will not be passed on to the next generation. When that animal dies, that mutation will die with it. Why some organisms reproduce a ...


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Yes there are some fundamental differences Different types of water the main challenge with aquariums compared with breeding terrestrial life, is that water differs a lot across the world, while the composition of air is virtually the same everywhere, whether over jungles, deserts, oceans or even cities. Fish from the amazon rivers require slightly acidic ...



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