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Questions tagged [growth]

In reference to a biological system over time, growth refers to the increase in physical size/mass as well as the progression through its life cycle.

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When do growth curves "reach maximum"?

I have been reading about growth curves, specifically those with upper and lower asymptotes, which have been asked about here before. See also Tjørve & Tjørve (2017). In these models, is there a ...
Azor Ahai -him-'s user avatar
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How do I grow 5 liters of purple non-sulfur bacteria?

I am running experiments for a project that requires large amounts of purple non-sulfur, Cyanobacteria and nitrogen fixing bacteria. I plan on growing all the species in separate tanks. The species' I ...
Aakarsh Tathachar's user avatar
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How do roots of a seedling know the direction to grow?

When a seedling starts to grow covered by soil, I thought directions are clear: Roots grow following gravity (down to the water), and the cotyledons (right word?) grow against gravity, so that they'...
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Reasons behind the sticky substances are used by poplar in buds

It is well known that sticky poplar buds falling on a car can seriously damage the paint. Also these scales from poplar stick to the paws and fur of animals like Velcro. Personally I don’t think the ...
Mikhail Gaichenkov's user avatar
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Why do short hairs get longer with age?

I know that short hairs such as eyebrows, eyelashes, nasal hairs will stay a certain length because the lifespan of the follicle only allows them to grow to a certain length. My question is why do ...
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Which plants are best for experiments about plant growth? [closed]

I was assigned writing a term paper about optimizing plant growth using control systems. This assignment is part of a class on sustainable energy usage, which means it's primarily on physics and ...
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Is it viable to make liquid potassium ferilizer through dissolving very small amounts of potassium chloride in water

I wasn't able to find fertiliser online that was simply potassium chloride and I didnt want to source my potassium chloride solution from potassium sulphate or other general NPK fertilisers for my ...
Malhar Kookada's user avatar
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Sigmoidal Curve in Geometric Growth

Here is an excerpt from my textbook: Let us now see what happens in geometrical growth. In most systems, the initial growth is slow (lag phase), and it increases rapidly thereafter – at an ...
Aditya Kumar Panda's user avatar
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Auxin-what happens to the auxin chemicals if the Sun is just above the plant?

The Auxins goes to the shady side for the elongation of the cell. This moves depending on the direction of sunlight. But, what happens to the auxin chemicals if the Sun is just above the plant?
Steve's user avatar
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Larval abalone devlopmental times - what does ~ °C.days or °C hr-1 mean

I'm looking a number of papers on abalone larval development and the term °C.days or °C hrs-1 keeps coming up. The numbers before these terms are much larger than they would be if this term actually ...
timeywimey's user avatar
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Refuge impact on growth rate

I have a question related to the refuge effect in ecological models. The assumption is that the population of hosts/prey is divided into two groups. One group consists of individuals that are safe ...
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The animal with the fastest hair growing rate

we know that human hair usually grows about 1/2 inch a month. My question is what is the species with the fastest hair growing rate? (including fur for example).
the correct answer's user avatar
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scientific reasons behind a a sudden yet temporary growth sprout of the plant when the soil has No depth?

Sorry, I'm kind of naive when it comes to plant biology. Mark 4:5-6( New American Standard Bible 1995 ) 5 Other seed fell on the rocky ground where it did not have much soil; and immediately it ...
crazyTech's user avatar
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There are some species that grow throughout their lives -- is there evidence that even in adulthood their brains increase in size?

One species I have read about is carp whose growth is limited only by food supply and space. One can actually, because their skin is almost transparent, see their brains and it sure does look like ...
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Can plants grow healthily being watered in either deionized or distilled water? [closed]

I want to use deionized/distilled water to water plants from some. I have the choice whether to use tap water, deionized water or distilled water that come from a closed system that has a water cycle, ...
Gal Grünfeld's user avatar
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Which approach is the common one in the literature for determining the bacterial growth rate?

I have the following data, which is OD600 (the second component) vs. time (the first component): ...
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Biology Experiment Algae pH & temperature help?

I am planning a Biology investigation for my IB IA on the impact of temperature and pH on algae growth. Does anyone have tips on how to measure the growth rate of algae? What algae is the most suited ...
Antonia's user avatar
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Make plant experience 2 growing seasons per year by moving it across equator semiyearly

If I take a typical plant (such as e.g. a rosemary plant or an avocado sapling) across the equator from Florida to Brazil and back every year, so that the plant experiences Spring in both places, will ...
user257566's user avatar
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How long to regrow hair?

This is one of the questions I wasn't exactly sure where to post. Basically, I want to make an X-Men parody, and for the part of Professor X I need to shave off my hair. Now I have a simple french ...
Mat NX's user avatar
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Do slime mold expand or multiply?

After reading about slime mold I was wondering, do slime mold simply expand outwards or multiply? e.g. if I put 100 grams of slime mold in 1 location, will it expand to say, 2 locations, and have the ...
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Is there a favoured mathematical model of bacterial growth?

One of the most regularly measured phenotypes in bacterial synthetic biology is growth. Anyone who does wet lab microbiology or synthetic biology will have performed a growth curve measurement. ...
ajhfedorec's user avatar
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Growing Penicillium Digitatum Mold

I left a cup of tea with Lemmon on my desk and after a while green mold start growing on the water. From my understating this is Penicillium digitatum. I gave it some sugar and after one day black ...
ziv's user avatar
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Why is DNA replication so much faster in prokaryotes than eukaryotes?

There are many statements to be found on the internet of the sort: “DNA replication occurs at elongation rates of about 500 nucleotides per second in bacteria and about 50 nucleotides per second in ...
1ijk's user avatar
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What is the mechanism through which fractals arise in plants and animals?

Many biological organisms -- such as trees, broccoli, and the blood vessels in animals -- can be approximately described using fractals. What is the reason behind such fractals? Specifically, do we ...
J Li's user avatar
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Is it possible to determine the initial population given the final one?

It is possible to determine the initial population of, say, bacteria given a measure at a later time? Let's say I use the logistic growth model $$\dot N (t) = rN(t)\left(1 - \frac{N(t)}{K}\right)$$ ...
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Giant insects growing question

During the dinosaurs time 100-200 million years ago there were giant insects like 1 meter long. An example is here. One of the theories why they could grow this big is that oxygen level was much ...
Zlelik's user avatar
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Do babies have a fight or flight response?

Do babies react in the same way as young children and adults in regards to the fight or flight response? If they do not respond in a similar way or don't have a fight or flight response at all then at ...
James's user avatar
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Why is cognitive maturity related to organism lifespan in larger animals and mammals?

I am not a student of biology, so I should provide some context to me asking this rudimentary question. While doing a graduate-level course on Reinforcement Learning, the instructors focused on how we ...
Abhinav's user avatar
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6 votes
1 answer
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Trees growing around objects vs pushing them away. Where is the threshold?

If a tree grows against a taut wire then the tree will grow around it, eventually enveloping the entire wire. This often scars the tree, and if the wire is thick enough, it will interrupt nutrient ...
bitsmack's user avatar
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What to do with this Araucaria sprout

I live in Santiago, Chile, and I see this Araucaria frequently: For what I have read, it seems to be a female A. angustifolia individual (leaves are 2-3 cm long and a few mm wide, with a very sharp ...
Rafael's user avatar
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A question about microbes growing media

I was told in my microbiology course that blood agar can be put in GasPak system (anearobic) to grow strict anaerobes, but why would someone use blood-dependent bacteria in this experiment as these ...
mohamed's user avatar
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2 answers
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Can the human body store protein?

I am interested to know if a human body can store protein. Absolutely for the bodybuilders, does it really matter if they divide their protein consumption during the day or eat all of it in one meal ...
user3486308's user avatar
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Is any animal born adult-size?

Size growth after birth seems to be the norm in the animal kingdom (as well as among plants). This makes sense. It's evidently physically challenging for an animal to produce an offspring of its equal ...
luchonacho's user avatar
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2 answers
105 views

What is the substance that tumors release that stimulates growth of blood vessels but suppresses its release from other tumors?

I'm currently in high school and I am working on a cancer research project. My project consists of a cancer, and different ways to treat it. I have a set of benign tumor and I was thinking of ...
Arush Agarampur's user avatar
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1 answer
1k views

What happens to plants if they are exposed to "sunlight" 24h a day?

I just wondered if one could grow plants faster, if they were exposed to sunlight-like light all the time. In a similar question which is not the same, I could confirm that plants have different ...
Martin Thoma's user avatar
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Alternative to Lotka Volterra

Would you guys know any kind of differential equations that would dictate population growth without relying on Lotka Volterra ? Thanks ^^
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Bacterial Growth Formula

What are the units of $N$: the colonies of bacteria or the viable cell count? This is in regards to the bacterial growth formula used during serial dilutions, $$ N =N(0) e^{kt} \quad . $$
biology1's user avatar
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Age until physical growth ceases, mammals

Fairly basic, but I am seeking a table showing how many years from birth it takes for the best-known mammals to stop growing. (Including the latest on humans - ie. 0-17..?).
Iain Sanders's user avatar
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Per Capita Population Growth Rate and Exponential Growth. Rate constants

As many of us might know, the set up of a differential equation relating instantaneous population growth with respect to time to the per capita population growth rate and current population size at an ...
MattGeo's user avatar
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1 answer
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Growth rate oscillation in the a population of non-interacting bacteria

I have come across this theoretical paper claiming that if you start a batch culture from a single E. coli cell, the exponential growth rate of the population defined as $$k = \frac1N \frac{dN}{dt}$$ ...
stochastic's user avatar
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What do bones need to grow outside the body?

In what environment outside of a living organism can bones grow? If I were to put an arbitrary human bone in a room and attach a bunch of tubes to it, or dunk it in some kind of solution, where would ...
boxcartenant's user avatar
8 votes
2 answers
4k views

What are the evolutionary reasons behind men being taller than women?

Human men and women are sexually dimorphic: there are some phenotypic differences between men and women. Men being taller than women is an accurate stereotype. Overall, men are on average 13 ...
C. Crt's user avatar
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6 votes
1 answer
450 views

Why does eyebrow growth stop after it reaches a specific length?

When compared to hair that grows forever after we cut it, why do eyebrows stop growing? What genes measure current length of eyebrow to ensure it stops growing after a specific length?
Mohammad Fajar's user avatar
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The correlation between a leaf's age and its length in the initial stage of growth [closed]

I am building a machine learning algorithm which predicts the age of a leaf before its maturity period based on its measured length or area. I would like to know whether there is a mathematical ...
Siddhant Kumar's user avatar
1 vote
1 answer
121 views

What is Growth and how can we define it to be a defining property of life?

I was reading a book and it said that internal/intrinsic growth is defining property of life and not extrinsic growth as saying accumulation of dust on a book makes it a bit bigger, even if it is by a ...
Abner Alfred Thompson's user avatar
2 votes
0 answers
56 views

Archenteron vs Gastrocoele

What is Difference between “Archenteron” and “Gastrocoele”. Are they same or different? Gastrula is characterized by Archenteron or Gastrocoele or Both?
user334272's user avatar
1 vote
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29 views

Beyond anabolism, what are factors that restrict growth rate?

Beyond obvious constraints in the case of nutrient limitation, what can explain the relatively slow growth rate of cells in rich media? Lab strains of E. coli grow really, really fast. The cell ...
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3 votes
2 answers
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How do I determine this logistic growth model formula?

The Question Two yeast cells were placed into a special container to which food was continually added, to keep it at a constant concentration. All other factors were set for optimal yeast ...
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1 answer
361 views

Since frogs are ectotherms and supposed to have low metabolic rate, why do they grow so fast and eat so much?

It's always emphasized in literature that endothermy enables high growth rates but requires more food. But look at frogs, for example: bullfrogs, toads, pacman frogs etc. They would readily eat a ...
A.V. Arno's user avatar
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13 votes
6 answers
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Why do seeds grow upwards?

Why do seeds grow upwards? Surely gravity would pull them towards the earth's core? Can anyone shine any light on this? Do seeds that are planted deeper grow more quickly.
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