Changes in the heritable attributes of populations of organisms over time. The mechanisms of evolution are mutation, migration, drift, and selection.

learn more… | top users | synonyms

3
votes
1answer
38 views

What is the purpose of narwals' tusks?

I've heard that narwals can grow their tusks up to 16 ft long. What do they need the tusk for? Hunting? Comunication?
3
votes
1answer
85 views

Mutation Rate in Multicellular Eukaryotes

I always hear people saying that the mutation rate is around $10^{-6}$ or $10^{-7}$. I don't even know if this number is the mutation rate of genes or of a single nucleotides and I actually (almost) ...
3
votes
1answer
215 views

Fecundity per woman in early humans

The average fecundity per woman varies a lot from country to country. I call average fecundity per woman the average number of born children per woman. In Homo sapiens, what was the average fecundity ...
3
votes
1answer
263 views

What's the purpose of colorful mushrooms' caps?

What's the purpose for many mushrooms to have colorful caps? Is not it is in their interest to hide as well as possible? Or there are mushrooms that propagate by being eaten, like fruits? Why not all ...
3
votes
1answer
1k views

Soft and Hard selection

Seems to me that these two sources (M. Whitlock, B. Wallace) use different definitions of soft and hard selection. M. Whitlock: Soft selection occurs when the relative fitness of an individual is ...
3
votes
1answer
166 views

Senescence, immortality and evolution?

Many have heard about the fabled "immortal" jellyfish, Turritopsis dohrnii, which doesn't die from aging (senescence) and can revert the aging process indefinitely. It is rather remarkable that only ...
3
votes
1answer
176 views

Are people genetically predisposed to being interested in specific fields/ideas? How does specialization occur?

I'm not sure if I formulated my question well, but I'm curious about a couple statements made by Steven Pinker and and James Heckman. In this interview: ...
3
votes
2answers
99 views

Heterozygosity under genetic drift

The wright-Fisher model of genetic drift is: $$p_{ij} = \binom{2N}{j}\left(\frac{i}{2N}\right)^j \left(1- \frac{i}{2N}\right)^{2N-j} $$ ,where $\binom{2N}{j}$ is a binomial coefficient. From this ...
3
votes
1answer
109 views

Evolution from Mating types to different sexes

Imagine a lineage of multicellular organisms that had mating types and evolved their mating types into sexes. What are the possible mechanisms that might have brought this lineage to evolve sexes from ...
3
votes
1answer
544 views

Why do genetic drift generates negative linkage disequilibrium?

The very first sentence of the abstract of this article is: "In finite populations subject to selection, genetic drift generates negative linkage disequilibrium, on average, even if selection acts ...
3
votes
1answer
389 views

Opposite results between Blomberg's K and phylogenetic signal in Phylocom (AOT)

I've been trying to test for significant phylogenetic conservatism in some plant traits. So far I used R-package picante (Blomberg's K) and AOT in Phylocom. So far these two methods yield completely ...
3
votes
4answers
195 views

How did the activities of protocells become inheritable?

I have learned that first a protocell came to exist and its characteristics came to be passed on by genetic material. So how come genes for all the activities come to incorporate into genetic ...
3
votes
1answer
75 views

Historical recovery from mass extinction events

Is there a way to generally characterize how species "regrew" after the various mass extinction events happening periodically from 450 Ma to 65 Ma. Would the surviving species just start back where ...
3
votes
1answer
83 views

Nucleotide frequencies in Kimura's two-parameter model

Here's an excerpt about Kimura's two-parameter model from Felsenstein's Inferring Phylogenies: "The model is symmetrical, and one can immediately see that, after enough time has elapsed, it ...
3
votes
2answers
54 views

Current scientific theories for evolution of Cucurbita

I'm attempting to find research on scientific theories surrounding the evolution of certain plants, and am unable to find any footing with respect to a certain genus. In this case, I am researching ...
3
votes
1answer
133 views

Why does Citric Acid occur in Citrus fruits?

Why is there so much citric acid in citrus fruits? And how did it evolve i.e. what did it come from? Is it a by-product of the ripening process? Why have citrus fruit evolved a particularly high ...
3
votes
1answer
138 views

Are there examples of animals that adapt to their environment very quickly? The phenomenon is called Phenoptic Plasticity [closed]

Evolution and speciation may take millions of years. This made me wonder if there is an animal that adapts itself relatively rapidly to its environment? I don't mean a simple adaptation like a change ...
3
votes
1answer
106 views

Why do cows (and other hooved animals) need a hierarchy?

Clearly numerous animals have a hierarchy - hereditary one. For example, I understand zebras have a pecking order, and must map this hierarchy from highest to first in line and lowest to last in line ...
3
votes
1answer
165 views

Why do spiders make their web near the ceiling and near a light source?

Why do spiders make their webs near the ceiling and near light sources ? Is their an advantage for spiders in doing that? For example do they catch more insects when their web is near a light source ...
3
votes
1answer
2k views

Differences between Gradualism and Uniformitarianism

From what I understand, gradualism is the idea that small changes affect species over time. Uniformitarianism argues that the same processes that occurred in the past are the same as those in the ...
3
votes
1answer
69 views

What is the most recent well-attested common ancestor of chimpanzees and humans?

Humans and chimpanzees are related and thus have a most recent common ancestor. Of course pinning down this precise point is essentially impossible, so I'm interested in close ancestors of this most ...
3
votes
1answer
183 views

Horizontal gene transfer versus convergent evolution

There are several often noted examples of convergent evolution (eyes, bat/bird wing evolution etc.) How do we rule out horizontal gene transfer in these cases?
3
votes
1answer
732 views

How does GC-content evolve?

Background GC-content refers to the frequency of base pairs that are either C or G in the genome, or in other words the number of GC base pairs divided by the addition of the number of GC base pairs ...
3
votes
1answer
134 views

Book recommendation on selective breeding?

I am looking for a good book that gives a nice overview of the science and technics of selective breeding. I am particularly interested in the use of population genetics to support decision in this ...
3
votes
1answer
101 views

Chromosome 2 alternate explanation - apes gaining a set of chromosomes?

I'm preparing for a debate (just between friends) on evolution (I'm in support), and one of the points I plan to bring up is the Chromosome 2 evidence. I'm now trying to predict their potential ...
3
votes
1answer
84 views

Chemoautotrophy in large organisms?

The major nutritional mechanisms include chemoautotrophy, heterotrophy (including parasitism and saprotrophy) and photoautotrophy. All of these modes of nutrition developed first in prokaryotic ...
3
votes
1answer
171 views

Empirical evidence for Group Selection?

A controversial concept in Biology "Group Selection", has caused confusion and conflict amongst scientists since the since the mid 1990s. The more general realm of study is termed the "unit of ...
3
votes
1answer
55 views

Are there cannibalistic k-selectors?

My understanding of r- and k-selectors does not go deeper than the wikipedia article. I understand k-selectors to be creatures that put tendentially more effort and energy into rearing their ...
3
votes
1answer
41 views

Estimation of number of species at an earlier time

The estimated number of species on Earth, as reported in this article is around 8.7 million. I am fascinated by how nature produces such a wide variety of species. As per my understanding, many ...
3
votes
3answers
3k views

Why does the apex of the human heart usually point to the left?

In the majority of human beings, the apex of the heart (left ventricle) points towards the left side of the body. Sometimes however (approx. 1/12000 births), a person is born with a condition known ...
3
votes
2answers
250 views

Short-term Lamarckism in asexual single cell organisms

I was reading through the Karr et al. (2012) whole-cell computational model. One of the things they did was to induce single-gene disruptions in their model. They observed several to be fatal, but: ...
3
votes
0answers
31 views

Is diarrhoea advantageous to the microbe?

Diarrhoea is a common side effect of many feco-orally transmitted bacterial infections. How does diarrhoea help the pathogen? Should it not have a selective evolutionary advantage? Do all symptoms of ...
3
votes
0answers
43 views

Is $F_{ST}$ a probability and a correlation coefficient?

$F_{ST}$ is one of the most famous and most important statistics of all of evolutionary biology. Yet, many people misunderstand it or misuse the classical results from the literature on $F_{ST}$ ...
3
votes
1answer
45 views

Do animals other than humans dislike food sources that others seem to like?

Humans (especially children...) seem to dislike certain foods or drinks, that other humans seem to like. Common examples are coffee, french cheeses, milk, fish and cabbage. Are there examples of ...
3
votes
0answers
49 views

How did dolpins acquire the dorsal fin?

I had been thinking bout atavism when I saw a picture of a dolphin. I had seen it before, but suddenly the dorsal fin startled me. How did this dorsal fin evolve, especially, is it some atavism from ...
3
votes
0answers
33 views

Does the bending of a tree's trunk in the wind stimulate and strengthen root growth?

Recently Southern California experienced extreme wind velocities and afterwards the news reported over 300 trees had fallen in San Diego County. I had either heard or read somewhere that the action of ...
3
votes
0answers
72 views

Why doesn't lard taste good? [closed]

I mean looking from evolutionary perspective sugar tastes sweet and individuals that had this perception ate more sugar and survived and those that didn't perceive sugar as sweet didn't eat it and ...
3
votes
0answers
55 views

Do animals demonstrate target practice (i.e., playful accuracy behavior)?

Do animals demonstrate any sort of accuracy-motivated play? (please provide examples!) Consider most human sports and related hobbies. Most share the common goal of hitting a target or being ...
3
votes
0answers
52 views

Diffusion approximation to genetic drift

I am reading from the classical textbook Principles of Population Genetics, Hartl and Clark (pdf here). Introduction Let $f(p,x,t)$ denote the distribution of allele frequency $x$ at time $t$ ...
3
votes
0answers
35 views

Games with non-uniform interaction rates

Background: Many models in evolutionary game theory assume uniform interaction rates. For instance, consider the $2\times 2$ game: \begin{array}{l c c} & A & B \\ A & a & b \\ ...
3
votes
0answers
24 views

Why does our body exhibit bilateral symmetry? [duplicate]

Externally, we (humans) look symmetrical. However, internal organs don't show the same patterns of symmetry (heart being on the left side while the liver is on the right side, etc.). It is a bit ...
3
votes
0answers
81 views

What form of reproduction did the first land animals use?

What form of reproduction did the first animals on land use*? Were they hermaphrodites, or did they have male and female sexes? [Is there a proper term for sexual separation in a species?] Were any ...
3
votes
0answers
76 views

How to understand relatedness in an infinite island model?

My understanding is that the relatedness coefficient in kin selection models measures positive assortment. That is, altruism is more likely to evolve if altruists tend to interact with other ...
3
votes
4answers
169 views

The selective pressure of contraceptives

Does it seem probable that the existence of contraceptives (which has reduced human reproduction to below survival-level in many populations) will be a completely new selective pressure on human ...
3
votes
0answers
87 views

Understanding the meaning of $s$ and $t$ in a population genetics equation

Sewall Wright in this article (1937) at the end of page 313 gives the equation: $$\Delta q = (s+tq)q(1-q) \space\space\space\space\space\space\space\space\space(1)$$ This equation is an ...
3
votes
0answers
20 views

Evolutionary motivation behind number of neurons in DCMMP

I'm studying neuro-anatomy right now and I was surprised to learn that there are only three neurons along the Dorsal Column Medial Lemniscal Pathway (DMLP) which relays mechanical sensations from the ...
3
votes
0answers
119 views

Why do baby mammals tend to play? [closed]

Why do babies of any mammal tend to play ? From humans to small dog pups, cubs of a lion, baby bears, etc. *I am not sure if the tag I chose is correct or not. Please correct me if I'm wrong.
3
votes
0answers
56 views

$F_{ST}$ and the genetic variance in metapopulations

From this video (21'15''), the speaker gives the following formulae in order to calculate the between and among populations genetic variance from the $F_{ST}$: $$V_{Among Pop} = 2 F_{ST}V_G$$ ...
3
votes
0answers
64 views

Inbreeding Coefficient and Coefficient of Relationship

Wikipedia gives the following formula to calculate a "path of coefficient of relationship" between an ancestor $A$ and an offspring $O$: $$\rho_{AO} = 2^{-n} \left( \frac{1+f_A}{1+f_O} \right)^{1/2} ...
3
votes
0answers
29 views

What is the origin of viruses? How could they get both living and non-living characteristics? [duplicate]

I read that viruses are called intermediate between living and non-living particles. Well, if so, then where did they originate from? From living or non-living? If they originated from either living ...