Changes in the heritable attributes of populations of organisms over time. Major mechanisms include drift, natural selection, mutation, and gene flow (migration).

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Why are there no wheeled animals?

In physics, "almost everything is already discovered, and all that remains is to fill a few unimportant holes." (See Jolly.) Therefore, on Physics SE, people are veering off into different directions: ...
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0answers
23 views

Development and function of spindle cells

In his book How to Create a Mind author Ray Kurzweil makes some claims about spindle neurons that he provides no source for. Concretely he states that spindle cells: Involved in handling emotion ...
4
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4answers
2k views

How did this spider evolve to mimic exactly a human face and arms?

So I came across something terribly amazing today, that is, a video showing this species of peacock-spider, that literally, transforms into a human face waving his arms about. What could have ...
7
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4answers
263 views

How does Darwinian Evolution work?

Let me explain... A friend and I read some articles, part of a Biology book, and watched a video on evolution. We then tried to explain what Evolution is to each other. My friend said that Natural ...
29
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8answers
525 views

Has there been any observation of species adapting the evolution process?

I am very interested in the evolution of the evolution process itself. There are of course a lot of things that influence how evolution will work, but for this question, I am interested in things that ...
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1answer
5k views

Cats, Dogs and Bears - how are they related?

What is the ancestral relationship between cats, dogs and bears? I presume they are more closely related to one another than other paraphyletic clades of mammal. Which came first? What did their ...
3
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1answer
192 views

Does modern theory of evolution include modification of physical environment?

Does any branch of modern evolution theories include aspects of evolving organisms modifying the physical environment? An example from the evolution of life could be early stage introduction of ...
2
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1answer
119 views

Did modern alligators and caimans come from prehistoric crocodiles?

I know that crocodilians have been here since the time of the dinosaurs. I also know that crocodiles came first. But alligators have been here for a good 37 million years. Did alligators come from ...
9
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1answer
197 views

What do we know about the Last Universal Common Ancestor (LUCA)?

All life on Earth (bacteria, archaea, eukarya) is thought to have evolved from a common ancestor, or last universal common ancestor (LUCA). What do we know about the characteristics of LUCA based upon ...
2
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1answer
42 views

What is the difference between the Modern Synthesis and the Extended Synthesis?

The NCBI talks about "Evolution beyond neo-Darwinism: a new conceptual framework." (source). What is the difference between the Modern Synthesis and the Extended Synthesis?
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0answers
110 views

Why are hybrid offspring mostly sterile? [closed]

Hybrid infertility is a common trait in cross-species offspring. Most are sterile, as they do not produce viable gametes. Examples of this can include Ligers and Mules. Could modern advancement in ...
5
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2answers
416 views

Why cannot there be multiple sources for same species origins?

We often associate Africa as the geographical location of the origin of humans. Why cannot there exist multiple geographic locations of origin (given same environmental conditions)? The same ...
-3
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1answer
93 views

Are there different species of modern day humans? [duplicate]

I've been watching nature shows on Netflix (Wildest series) and different animals of the same "family" are actually different species. e.g. Asian elephants vs African elephants. Asian elephants are ...
4
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1answer
58 views

Which Darwin book (and today edition) is illustrated by his own drawings?

I am interested in buying Charles Darwin books and mostly drawings (nowadays editions, I am not a collector). Please, can you advise in which book and which edition I can find the most of his ...
3
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1answer
100 views

Do the claims in this paper have any degree of validity?

The paper The waiting time problem in a model hominin population talks about a problem of waiting time, etc. Is the methodology of this numerical simulation, and the conclusion right or is it wrong? ...
4
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2answers
271 views

How did zootoxins evolve?

I've always wondered how toxins in certain organisms have evolved. Particularly, organisms that produce toxins as a deterrent to predators as opposed to organisms that use it to paralyze their prey. ...
0
votes
1answer
161 views

How does the modern synthesis theory explain the evolution of birds from dinosaurs? [closed]

The theory of evolution claims that birds evolved from dinosaurs only by mutation, genetic drift, migration and natural selection. However, it seems to me that wings were not selectively advantageous ...
1
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0answers
25 views

Resources for similarity between embryos

Is there a scientific paper/reputable image resource out there which I can use that the embryos of different organisms (vertebrata) are similar in their early developmental stages(without falling into ...
3
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0answers
33 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 \\ ...
1
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1answer
51 views

How does discontinuous distribution provide evidence for evolution?

One of the evidences for evolution is biogeographical evidence. In it, 'discontinuous distribution' is mostly cited as an evidence. For example, Alligators are found only in south-eastern US & ...
3
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2answers
93 views

What does 'direction' mean in the statement “mutations are non-directional”?

I was reading the Mutation theory of De Vries; there I encountered this statement: Mutations are discontinuous, random & non-directional. This is in contrast to Darwinism where variations are ...
1
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1answer
78 views

Does the modern synthesis theory of evolution deny that acquired characteristics can be inherited? [duplicate]

The following is an wikipedia article on Lamarckism. https://en.wikipedia.org/wiki/Lamarckism According to Ernst Mayr, any Lamarckian theory involving the inheritance of acquired characters has ...
5
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0answers
56 views

Variance in Fst in the infinite island model

The most famous result in the study of structured populations come from Sewall Wright. He showed that in an island model, where each subpopulation is of size $N$ and the migration rate is $m$, then ...
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0answers
21 views

Replicator equation for mixed strategies?

The the replicator equation is usually defined for pure strategies. More specifically, the replicator eqn for $n$ strategies is given by: \begin{equation} \dot x_{i} = x_{i} \left( \sum_{j=1}^{n} ...
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3answers
64 views

Cancer a method for early Earth Evolution? [duplicate]

Something I have been wondering for a while is looking at cancer from an evolutionary standpoint. It's easy to conclude (from observations today) that cancer is something we would rather avoid. ...
1
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1answer
75 views

term for species that produces males only to mate with mother or sisters

In reading about unique reproductive strategies I've run into two closely related and comparatively unique mechanics. Both involved a female who was born 'pregnant' with at least a male, but the male ...
0
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1answer
19 views

Why Can't the passage of acquired behavior be considered acquired inheritance?

While reading about a cross-fostering experiment conducted on Male California mice and Peromyscus californicus, I came across the fact that the behavior acquired by a generation of mice due to ...
1
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1answer
47 views

Using evolution of bacteria against themselves

We know that mutations happen regularly in bacteria and also that one bacteria might get the mutation and become stronger than the others and thus survive, causing antibiotic resistance as well. Can ...
-1
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2answers
68 views

Why both sexes of the species don't show equal level of Competition? [closed]

In most species, it is seen that either males or females have evolved to be aggressive towards approaching members of the same species of the same sex and maintaining strict territorial boundaries. ...
2
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0answers
51 views

Why did humans evolve the ability to feel such a high level of heat pain? [closed]

It's probably because our ancestors were frequently around 300°C metal which badly damages flesh in a fraction of a second because they made fires to cook. I don't see why that would cause natural ...
4
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0answers
34 views

How “old” is a specific snake venom?

This is a World Building question, but it's biology specific (I think). I'm looking for an approximate answer on how long, evolutionary, a specific venom has been roughly the same. Is it pretty much ...
2
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1answer
92 views

Do mammals and birds have a common warm-blooded ancestor?

Is it homogeneous or did they converge? Did we both evolve from warm-blooded reptiles that are extinct maybe?
29
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3answers
3k views

How could humans have interbred with Neanderthals if we're a different species?

To be clear, I'm not doubting that homo sapiens and homo neanderthalensis did interbreed: of that much I'm convinced. Within the past few years I've seen an upcropping of pop-sci articles discussing ...
2
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0answers
51 views

Front versus back in animal anatomy [closed]

Throughout various species, there seems to be a clear distinction between the front and the back. The musculature of the front, when engaged, closes or curls up the body, protecting it, while the ...
2
votes
1answer
113 views

Why do spiders have a leaf at the bottom of a piece of web?

I've lately seen a lot of instances where a leaf is dangling from a piece of web coming down off a tree. What purpose/s does this serve for the spider? Is it some sort of mechanism for the spider to ...
1
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1answer
64 views

What is the evolutionary tradeoff against primates producing multiple offsprings (litter)?

If we evolved to have multiples all the time we would more likely have extended families living together in 1 house. This would be better than the spouses by themselves for multiple reasons including ...
0
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2answers
53 views

When did the most recent common ancestor of all living domestic dogs live?

Wikipedia provides a very detailed page on the origins of the domestic dog, but this fact does not seem to be present there. Google searches for terms such as "most recent common ancestor (MRCA) of ...
5
votes
2answers
563 views

Why do adult insects have 6 legs?

Apparently, there is an advantage to having 6 legs in the insect world. What is that advantage, if anything? Why would such an advantage exist for insects, but not for other, larger land animals? ...
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2answers
77 views

What causes goose bumps?

What is the actual process and reflexes that cause the goose bumps? Why is it an evolutionary advantage to have goose bumps in the first place?
9
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1answer
196 views

Expected time for a neutral allele to reach a frequency of $p_1$ when starting at frequency $p_0$

Kimura and Ohta (1968) showed that the expected time for a neutral allele to reach fixation (given that it will reach fixation) is $$\bar t(p_0)=-4N\left(\frac{1-p_0}{p_0}\right)\ln(1-p_0),$$ where ...
13
votes
4answers
2k views

Book recommendation on population/evolutionary genetics?

I have recently been involved in collaborations that require me to model the population genetics of eukaryotic populations. I fear I may either be "re-inventing the wheel" or making conceptual ...
26
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6answers
3k views

If a trait would be advantageous to an organism, why hasn't it evolved?

If a trait would be advantageous to an organism then why hasn't it evolved yet? Conversely, if a trait is not advantageous or mildly disadvantageous, why does it exist? In other words why does ...
1
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1answer
90 views

Is there an evolutionary advantage for coconut oils to be rich in saturated fats?

I know that coconut oil is composed of multiple saturated fatty acids, but is there a reason why this would have increased the fitness of the coconut plant?
2
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1answer
57 views

Discrete vs Continuous Replicator Dynamics

The replicator eqn in the case of discrete non-overlapping generations and asexual reproduction is given by the discrete replicator eqn: $$x_i(t+1) = x_i (t)\frac{f_i(t)}{\bar f (t)}$$ where $x_i$ is ...
44
votes
4answers
2k views

Why do men have nipples?

I'd be tempted to call nipples in men vestigial, but that suggests they have no modern function. They do have a function, of course, but only in women. So why do men (and all male mammals) have them? ...
11
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3answers
179 views

Why is iodine used for metabolic hormones?

Iodine and related biological iodine-carrying hormones are phylogenetically very old, at least according to Wikipedia. Humans use iodine as a metabolic indicator, as do axolotls and apparently most ...
4
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1answer
1k views

If oxygen is such a good energy source, why do plants release it?

Why do plants release excess oxygen, rather than consuming it entirely given it is an excellent energy source?
4
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2answers
150 views

Why do snakes not have eyelids?

Why is it that snakes do not have eyelids? Is it due to that fact that they are not as evolved as we humans and other organisms that have eye lids, or is there any other significance behind it if ...
33
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5answers
9k views

Why don't mammals have more than 4 limbs?

Arthropods have 6 or more limbs and arthropods with 6 limbs appear to move faster than arthropods with 8 limbs so I wonder whether this might have something to do with fast and efficient locomotion. ...
0
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1answer
52 views

What, if anything, would prevent flying fishes evolving to be capable of extended flight? [closed]

This extraordinary video documents a flying fish gliding above the surface of the sea for nearly two minutes. Occasionally it uses its tail for added impetus. It is possible to imagine a fish gliding ...