1

The Environment / Re: Are there references for atmospheric CO2 before 1900?

« on: 30/09/2017 08:09:11 »

Hi There,

thanks for the comments. I fear, they do not really help in the discussion I am having. The person is quite a conspiracy believer, sure of the fact, that media is controlled by big companies to promote their own interests, and human made climate change is an invention of sustainable companies to earn a heck load of money. That is another story and I do not want to discuss this part here now. I just want to give you a frame of what this source means for this person. He thinks, the older references (printed, to be sure it has not been fiddled around with) are more trustworthy than the newer references that take a look back into the past (and could therefore "change" it to their will).
That is why I would like to focus on this old reference as well and try to interpret it as best as I can.

I understand, that just dismissing this literature, that states the same CO2 values in the atmosphere as they are measured today will not benefit the discussion at all.

We now claim, that the CO2 in the atmosphere before the industrial times has been around 280 ppm. How do we know that? Is that data from the Icecores? Can they be that precisely dated?

Does anybody know how they measured the contents of the air back in 1800+? I found another source, that seems to state the contents of CO2 quite precisely under different conditions.It is german unfortunately (http://www.retrobibliothek.de/retrobib/seite.html?id=101252) from 1885-1892, but they compare different settings like coastal regions, desert regions, valleys and mountains and measure to the 3rd digit of volumen percent.

It is thus difficult to accept a just "they did not know what they did back then" without further explanations of why those numbers are not trustworthy... at least I would not accept such an answer, if it was dismissing one of my arguments.

Maybe someone has some good arguments on that... in whatever direction they go.

2

Plant Sciences, Zoology & Evolution / Re: Why birds stand on one leg when they rest and sleep?

« on: 15/05/2017 17:47:41 »

There have been two possible explanations for the resting on one leg.
One is, as jeffrey said, thermoregulation. This assumption is supported by several observations, like that herons, flamigos and suchlike stand more often on one leg when they are in water (good thermal conductor) as when they are on land. Also if it is really hot those bird will more often not retract their leg completely into the feathers. On the other hand they more often retract the legs up into the plumage if it is really cold.

Another explanation that has been widely discussed is whether the retracted leg helps to reduce muscle fatigue, similar to humans or other mammals (horses, elephants..) that usually put the bodyweight on one (hind-) leg when standing. However, this seems not very likely as retracting the leg rather seems to require the use of muscles that will get fatigued.

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Plant Sciences, Zoology & Evolution / Re: Do animals have weird dreams?

« on: 08/05/2017 16:48:00 »

Hi Ries,

as SquarishTriangle already pointed out, it is of course difficult to impossible to determine what an animal dreams. At least at the moment, it would be impossible to know what other people dream, if they would not be able to tell us about it.

From my annecdotal experience and a very anthropocentric point of view I believe that at least dogs do dream, and I would guess, that they also have very engaging dreams. I crew up with dogs and especially our first dog used to have quite intense situations during sleep involving running movements, snarling, growling, rapid eye movements, fawning, gasping and slight forms of barking regularly. In one case she even howeld like a wolf, a sound I never heard from her before or after that dream again. That was super weird and I swear (anthropomophizingly of course :-)) she had a very confused look in her face when we woke her up from this. Our other dogs also show some of those mentioned signs that would lead me to think that they dream.

However, this is purely annecdotal, even if many other pet owners can add their own stories to this.

Science also tried to tackle that question, if animals do dream at all.
We know from comparing EEG patterns of sleeping animals that many mammals and birds follow similar sleep patterns like humans with deep REM sleep phases alternating with lighter non-REM sleep phases. In humans the REM phases are the ones were we dream and it has been shown, that they are essential for memorizing.

The movements during sleep is one of the best observable hints we have for actual dreaming. There is a sleeping disorder in humans, where muscles will not be paralysed during REM-sleep, so that dreams get acted out by walking, punching, kicking..  This disorder exists also in domestic animals, suggesting that they do dream as well (you can finde videos of such animals if you search for REM sleep disorder in animals). Scientists also induced this disorder artificially to study cats during sleep in the 1960s, observing those animals acting out during REM-sleep, including walking an dfighting invisible opponents.
Some more studies are done on brain activity during sleep, showing in rats, that they relive their daily experiences and in zebra finches, that they memorize their bird songs during REM sleep.

So there is quite some behavioural and neurologcal evidence for animal dreams. Given the nature of dreams from our human experience, there is so far no reason to believe, that animals would exclusively dream of "normal" things, althought their "weird" might be something completely different from what we would expect it to be. However, in the end nobody knows and it might be impossible to ever know.

4

Plant Sciences, Zoology & Evolution / Re: Is it true puppies get the best out of both parent's genes?

« on: 22/04/2017 11:38:44 »

Hi Alan,

short answer: No... although it of course depends already on what someone would judge as "the best" in a parent. For example a breeder might rank some traits as favourable (e.g. coloration, a certain figure, short nose, hairstructure and so on) than someone with a medical backround would rank as bad (for example a short nose could make it more difficult for the animal to breath and should therefore not be desirable).

But even if we just consider the opinion of one person, it is not always the traits this person desires the most that will be passed on more likely.

For the longer answer, the basis for understanding what is going in the inheritance of traits are the Mendelian Laws of inheritance.
They basically say

a) In the genes each trait is coded for with two alleles, that migh look like this: Aa. When the trait gets passed on, the two alleles will separate into A and a and will recombine with the two alleles of this trait in the partner. So you will always have one allele of the mother and one of the father in the offspring to code for a trait. In this visualization the big letter is coding for a dominant allele, meaning that in a combination with a recessive allele the dominant one will be the one that gets expressed. The small letter is a recessive allele, meaning it is the one that gets supressed in a combination.

b) If the parents have a pure genetic backround for a certain trait (homogenous), for example the mother is a white dog (ww) and the father is a black dog (BB), then the emerging offspring will all be heterogenous (means, a trait is now not "purely" coded for anymore) and will all be the same. In this example alleles expressing "white" are recessive (small w) and alleles expressing black are dominant (big B). Therefore in this case all the emerging puppies would be black as all the new recombined alleles would look like this: Bw (B from the father and w from the mother). This kind of heredity is therefore called dominant-recessive. There is another possibility where the alleles from the mother have the same rank as the alleles from the father, so the offspring would for example look like this: BW .. in this case neither black nor white is dominant, so the offspring would possibly be grey. This is called intermediate heredity. So if the person ranking the traits would like to have white dogs, it would not be very happy with both scenarios.

3) However, you can get white dogs from this offspring again with a certain probability. If you now mate two individuals with heterogenous backround (Bw) you will now get offspring that might differ from each other quite a lot. All possible recombinations would now be those: BB (black dog, homogenous), Bw (black dog, heterogenous), ww (white dog, homogenous). Due to probability, the chance to get a white dog is only 1/4, as is for getting a homogenous balck dog. About half of the offspring will still be heterogenous and thus, while you would be sure that mating white dogs with each other would always produce white dogs, it is still difficult to say what offspring you would get in the next round if you use the black ones.

This is a simplified model, where one trait is coded for by just one allele. In reality traits are often coded for by several alleles and some alleles are responsible for several traits, making the whole thing a bit more complex.

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New Theories / Re: Is heterogenics the sole purpose of sex?

« on: 22/04/2017 10:07:08 »

Just some thoughts you might want to consider:

1) Many women (especially in their most receptible age) have trouble getting a orgasm by penile-vaginal intercourse alone. Actually, studies even found, that this is the case for the majority of women, up to 3/4 of all women never had a vaginal orgasm. It is therefore highly unlikely, that there has been a evolutionary selection for having vaginal orgasms. It might be just a byproduct. Your claim of the "evolutionary right way of coupling" is therefore not based on solid ground.
(for further read: e.g. Kim Wallens research like "Female Sexual Arousal: Genital Anatomy and Orgasm in Intercourse" or "Clitoral variability compared with penile variability supports nonadaptation of female orgasm.")

2) Although sexual behaviour surely evolved as

Last I heard, sexual reproduction evolved because it allowed genetic variation to improve the adaptability of species in changing environments.

it is by no means always clear what sexual behaviour in a species is all about. In many species it evolved to a social tool of bonding (many monogamous species) or to establishing hierarchy (e.g. rabbits). We should therefore be very careful in concluding about the "meaning of sex" from its origins.

3) I strongly disagree with the notion, that it is homosexuality that drives kids to early contact with sexuality. Just look in the media: television, movies, music ... they depict a lot of (hetero)sexuality. Never came to mind that this might force kids to deal with those cues?

4)

the majority will always be heterosexual even if one gender devolves back to singularity

That just does not make sense on so many levels.. it is per definition not possible to be heterosexual if there is only one sex... your theory of devolution is also highly unlikely.

5) So if homosexuals neglect orgasm in the opposite gender, do heterosexuals neglect the orgasm of members of their own sex and be therefore just as "physical dysfunctional or sociopathological"?

X) This went viral just recently, maybe think about it for a while:

    What do you think caused your heterosexuality?

    When did you decide you were a heterosexual?

    Is it possible your heterosexuality is just a phase you may grow out of?

    Why do you insist on flaunting your heterosexuality? Why can't you just be what you are and keep quiet about it?

    Why do you heterosexuals feel compelled to seduce others into your lifestyle?

    Have you considered therapy to change you heterosexual tendencies?

all the best

6

Plant Sciences, Zoology & Evolution / Re: How does water activate seed germination?

« on: 20/04/2017 14:22:58 »

Hi there,

I actually had to look it up in my old transcripts from plant physiology, but here is what I found:

The water is first absorbed by the seed. This can sometimes take a quite long time in the soil and often results in a softening and maybe even tearing of the outer cover of the seed and thereby makes it easier for the embryo to pierce through it eventually.
In the seed the water triggers the synthesis of gibberallic acid, an important growth hormon in plants. This hormon diffuses into the endosperm, the nutritive tissue for the embryo, where it activates the hydrolytic enzymes, which will begin to dispel the stored reserve material like starch and proteins into maltose and amino acids. Those metabolites then go to the embryo where they are used for the actions you described: cell elongation and division. Now the seedling can break through the softened or even torn outer cover of the seed and start to grow and to accumulate substances needed for further survival and growth.

7

Plant Sciences, Zoology & Evolution / Re: Why cant dogs eat chocolate?

« on: 17/04/2017 11:58:43 »

Hi Franki,

the toxic substance in chocolade is called theobromine.
In humans this substance is digested quite rapidly in the liver due to a certain enzyme of the Cytochrome P450 complex.
In dogs and other animals (cats, bears..) these enzymes are much less active and it takes upt to 3 times longer to digest the substance. Consequently theobromine is accumulating in the organism much faster than it can be digested, leading to high blood pressure as well as a lower limen in nerve cells. In the end the failure of the heart or the lungs lead to death.
How dangerous chocolade is for dogs also depends on the type of chocolade with darker types being more toxic as they contain more theobromine.

So the dogs up to ten times more aggressive gastric acid in comparison to humans does not help them in this case, as it is enzymes that break down theobromine.

all the best
Aj

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Plant Sciences, Zoology & Evolution / Re: How is frogspawn fertilised?

« on: 17/04/2017 11:09:56 »

But surely the biggest, burliest male is the "best" parent because he's strong enough to have fought off the competition and protected his female during the mating period?

Additionally to what SquarishTriangle said: it is not always the strongest and best suited male that win the price. In some species smaller and less competitive males might go for another strategy. Instead of directly competing with bigger (e.g. usually louder if display is based on vocalization) male they wait nearby in silence until a female got attracted by the lovely sound the big male produces. The smaller satelite male will then try to intercept the female and trick her to get into the amplexus. Once in this position the smaller male has an advantage over otherwise maybe more competitive males.

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Plant Sciences, Zoology & Evolution / Re: Why aren't algae and fungi in the plant kingdom?

« on: 16/04/2017 14:16:19 »

Hi Ravindra,

The classification of life follows universal rules to arrange different units of life in a meaningful way.
On the highest ranking level (domain) life is divided due to molecularbiological reasons into Bacteria, Archea and Eucaryota. Animals, plants and fungi belong to the Eucaryota and are further divided into their subtaxa on the basis of general differences between those (and other) groups and similiarities within them.

Other than fungi and animals plants are usually autotroph. That means that they are able to survive and grow solely on anorganic components. Animals and fungi on the other hand need anorganic as well as organic components (heterotroph), which are for example provided by plants. On the celular level plants show a cell wall, which is missing in animals but can be found in fungi. Animal cells are surrounded by a flexible membrane instead.
There are several other differences, but those mentioned already show a general picture of how those taxa differ between each other.

plants: cell wall, autotroph
fungi: cell wall, heterotroph
animal: cell membran, hetertroph

In the end it is a combination of differences and similarities that determine if a lifeform belongs to e certain clade or not.

So to come to your actual question:
"Algae" is a biologically unclean term. It does not only descripe a complete multitute of species that can all be traced back to a single ancestor (monophyletic) but encompasses many different species derived from different ancestors (polyphyletic). So not all so-called algae belong to the plants (green algae/chlorophyta). For example the so-called blue-green algae are actually bacteria not even belonging to the same domain as animals, fungi and plants and are nowadays correctly refered to as Cyanobacteria. Red algae are an own clade not belonging to plants as well (one main difference to plants is in how they store energy and the cell walls are organized in a different way). Brown algae are another example belonging to another clade.
However, als all algae have cell walls, are able to do photosynthesis due to heterocont plastids and are thus autotroph, they are clearly not animals.

The fungi have been included in the plant taxon for a long time but nowadays they are their own taxon which is viewed as beeing more closely related to animals then plants. They have some similarities to animals like their heterotroph diet, which they digest using enzymes and they both store energy as glycogen, not as starch like plants. Like insects they use chitin for stabilisation.
However, they have a cell wall and vacuoles unlike animals and the cytoplasm in the cells can move via cyclosis (not seen in animals).
Plants and animals on the other hand share, that they can form biological tissues, an ability fungi lack to have.
So all in all

To wrap this up we can extent the overview from before maybe a bit to show where the differences are and were the similarities (no claim to completeness!)

plants: cell wall, autotroph, plastids, tissues, store energy as starch
fungi: cell wall, heterotroph, no plastids, no tissues, store energy as glycogen
animal: cell membrane, heterotroph, no plastids, tissues, store energy as glycogen
(algae: cell walls, autotroph, plastids, but differences between different types of algae e.g. in energy storage)

All the best
Aj

10

Plant Sciences, Zoology & Evolution / Re: How is frogspawn fertilised?

« on: 16/04/2017 11:58:19 »

Yes, exactly.
However, it has been found that in cases where frogs reproduce in one big mating bout all at once (e.g. Rana species) a females eggs are not seldom (up to more then 50% of egg clutches) fertilized by more than one male. In those mating systems where they release eggs and sperm in the open water (also in many fish) it is very difficult for the male to ensure exclusive paternity, especially if they are explosive breeders, that spawn in maybe only a few hours. It has been argued due to the fact that the sperm concentration of the water is very high during those hours it is likely, that sperm of other males can reach also other eggs produced by females nearby. But with behaviours like the amplexus in many amphibians the male can significantly increase its chances of fertilizing most of the females eggs.

Ensuring paternity is often easier with internal fertilization.. but not as a general rule. In many internally fertilized species multiple paternities are still common due to females mating with multiple males, resulting in sperm competition, cryptic female choice or even males having evolveld certain active strategies like clearing out the spermatheca where the female stores sperm before ejaculating or sealing up the females genitalia to prevent other males from mating with her or simply guarding her for the same reason. Reproduction is a war! :-)

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Plant Sciences, Zoology & Evolution / Re: How is frogspawn fertilised?

« on: 16/04/2017 11:13:16 »

As many frogs are externally fertilized the fact that the sperm finds the egg can be especially remarkable. For the male, to ensure to fertilize as many eggs as possible, it is essential to release its sperm very close to the females cloaca when she is laying her eggs, as frog sperm is typically not very mobile. Those frogs one would typically observe in mating in large numbers in ponds or other water bodies usually produce a large amount of sperm to ensure at least some to find the eggs. The egg cell is releasing certain proteins to attract the sperm cells and is then binding the sperm cells with the help of another protein that is conained in the egg jelly. The sperm has then to find its way trough the jelly to the egg cell to be actually able to fertilize it. It has been shown, that sperm cells that are motile but swim slowly and steadily are more successfull in reaching the egg in the end than fast but unsteadily swimming sperm cells. Those often get trapped in the jelly and never make its way trough to the actual egg cell.
SquarishTriangle descriped pretty nicely how it goes on from there for the sperm cells, that actually made its way.

all the best

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Plant Sciences, Zoology & Evolution / Re: Should we allow extinctions as a part of evolution?

« on: 15/04/2017 11:34:14 »

Hi John,

in principle, you are right. Nature itself has seen a lot of extinctions and it actually "does not care" if some species vanish from the earth or not.
It is, however, a misimpression that nature conservation or species conservation is in general a selfless act just done to protect nature for it´s intrinsic values. Although some people might feel that those intrinsic values are enough reason to try to safe nature or parts of it, on the grand scale, conservation efforts of any kind are only convincingly justified by taking humans into account. It is usually anthropozentric reasoning that makes us invest in nature conservation. Trying to sustain nature as it is at the moment is a logical step for as species in the aim to preserve itself. The "current" situation has been proven to be able to support humankind. Or to look at it from the other side - we adapted to this situation best and know how to deal with it. Every change, especially when not fully predictable, poses a risk to humankind. It might take us a while to adapt to new conditions, entailing calamities and maybe death of thousands. In the worst case the new cicumstances will never allow us to conserve or even improve our life standarts.
People realized quite early, that we need to protect what is supporting us. That we can not just overexploit nature without consequences. So first steps into our modern understanding of nature conservation were taken by the economy. The concept of sustainability, a major concept in modern conservation efforts, was implemented by forestry in the early 17hundreds when people realized that wood would not just grow back in the same rate as it was taken out of the forests, and that something needed to be done to sustain the supply. There is a lot of annecdotes that tell a story about how very anthropocentric reasons ensured survival of a species in the end (e.g. the indian lions in the Gir-forest, first protected because a sovereign at that time showed interest in being able to hunt them in future).
Fact is, that we just start to understand some of the very complicated relationships species have within nature. Even if we do not have a direct interest (economical, functional, medical, recreation ..) in a certain species now, we have to consider, that this species might bear information we might need later on in our intelectual evolution or that its disapperance might trigger a chain reaction that we are not able to foresee now because we were not able to assess its full function in the food web.

While I believe that also intrinsic values should be good enough to protect a certain species, I know not everyone shares this opinion. I am therefore also convinced that this argumentation is in the end not good enough to activate nature conservation efforts, especially as soon as money and effort is involved. But I am also cocksure, that there are a lot of good anthropocentric reasons to be carefull with nature and try not to mess to much with what we got.

all the best
Aj