The biological process by which new individuals are formed.

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323 views

What animals stop other members of their species from mating and why?

(In particular primates) I know chimps do. Powerful alpha males chimp would beat up omega males that they caught mating. I know gorillas do. Powerful alpha males gorillas would beat up omega males ...
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38 views

What are some difficulties animals had to overcome to reproduce on land?

This is for AP Biology, but the assigned textbook chapter doesn't contain any information about the question. What are some difficulties animals had to overcome to reproduce on land? Some ...
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63 views

What is the difference between embryology and developmental biology?

The question is quite explanatory in it self, I used to think that both are same but then find somewhere that embryology is a part of developmental biology, can somebody please elucidate?
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29 views

Effect of the health of the male parent at the time of conceiving

Does it matter at all in determining the traits of a baby what the current health of the father is? For example, let's say I got diabetes at the age of 40 because of the poor lifestyle choices. Will ...
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111 views

Bacterial Conjugation/Horizontal Gene Transfer — how does the plasmid exchange work?

So according to a PPT I'm reading, bacterial conjugation works by the two bacteria joining pili and exchanging plasmids. So how exactly do the plasmids get across the gap? If I understand this ...
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1answer
37 views

Book on yeast reproduction, evolution and on the use of yeast as model organism

I am looking for a good book in: Yeast reproduction mating types Recombination mating type determination mechanism Yeast evolution Yeast as model organism and its use in experimental biology It ...
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66 views

Terms related to megasporogenesis

Well, I am not able to understand the exact difference between megasporocyte and archesporium. Also I'm not quite able to get, how or precisely from where do these arise? Please help.
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133 views

Is there a human form of estrus?

Now I just learn that estrus is a trait in all mammals except Humans. So does it occur significantly in Humans? Of course I'm aware of the cliched "horny", "aroused" etc., but is it a biological ...
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29 views

How does proximal centriole of human sperm function?

I've read that the human's unfertilized oocyte ( stuck at metaphase 2 of meiosis ) lacks centrioles and that it completes meiosis 2 after fertilization as sperm gives its proximal centriole. Then what ...
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24 views

Are there multicellular isogamous species?

Are there multicellular isogamous species? Seeking through the examples of wikipedia I would tend to think that there are no multicellular isogamous species.
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31 views

Role of Calcium and Magnesium in capacitation/acrosome reaction

During the acrosome reaction, the activation enzyme present in the sperm dissolves the corona radiata and zona pellucida enabling the sperm to reach the plasma membrane of the egg. Also calcium and ...
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52 views

Mutated Sperm - What happens?

I saw on TV that not all sperm are the same. Some have mutations like 2 and 3 tails? There were other mutations as well. If one of these mutated sperm actually fertilized an egg, would the embryo ...
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23 views

recombinant gametes

Suppose you are able to observe under a microscope the total number of meiotic divisions occurring in one gonad of a given individual and to outnumber exactly the crossovers between two given ...
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46 views

Why does the ovum prefers to be arrested at metaphase 2 of meosis before fertilization? What is the possible advantage of this process?

Why does the human ovum prefers to be arrested at metaphase 2 of meosis before fertilization? What is the possible advantage of this process??Please help me with it.
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103 views

Why do some animals and fungi prefer asexual reproduction?

Animals like Sponges and Hydra and fungi like Yeast and Mushroom can reproduce both asexually and sexually. However, they only reproduce sexually if the 'circumstances' are 'bad'. Is there a specific ...
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0answers
25 views

Is there a database of pollen-seed distances across plant species?

I was enjoying Richard Smith's excellent answer to this question, and wondered: If you consider the pollen/seed distribution range to be plant locomotion, is there a database that compares these ...
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1answer
95 views

How might IVF (and related technologies) alter epigenetic marks?

I was reading up on KCNQ1, which encodes a voltage-gated potassium channel, and I discovered that it happens to be only maternally expressed. This is regulated by KCNQ1OT1, a non-coding RNA, which is ...
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81 views

Can mammals from different species reproduce? [closed]

I'm curious on how genetically different can two animals be in order to reproduce. Could they belong to different species? One example is the mule which is the offspring of a donkey and a horse, in ...
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98 views

Why aren't antheridia and archegonia touching?

Antheridia and archegonia are the two male and female gametangia, respectively, and they are found in bryophytes. To cause fertilization, usually a thin film of water must be present for the sperm ...
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4answers
1k views

Are chromosomes from each parent split between gametes with equal probability (esp. in humans)?

I've recently read a little on Wikipedia about genetics, but I can't find a direct answer to this question. My rough understanding is this: Both males and females have pairs of chromosomes, one ...
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55 views

Male behaviour during breeding season

The mountain blue bird build nests to attract females and exhibit aggression towards other males during breeding season. Which of the following is likely to give the birds maximal evolutionary ...
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1answer
70 views

Can ovulation and menstruation occur simultaneously?

Is that possible that ovulation happens in the time of actual menstrual haemorrhage in human females - let say in a case that woman has 21 day cycle and her menstrual period is 7 days? If yes, does ...
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28 views

Regarding inherited fertility in animals

If an animal is fertile does it follow that both its parents of the same species (not necessarily the same species of the offspring)? Was it Mayer who said a fertile male and fertile female of two ...
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1answer
50 views

Are there other methods besides surgery and hormonal treatments to help undescended testicles? [closed]

I've been doing some reading on undescended testicles and common treatments. It looks like the most common treatment for a baby is to give it time to see if the testicles drop on their own. If not, ...
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160 views

Need of X or Y chromosome protein after meiosis

After meiosis each spermatid get either the X chromosome or the Y chromosome. I know that the 4 spermatids formed from 1 spermatogonia are connected by cytoplasm and so the proteins made by X or Y ...
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303 views

Negative role of Placenta

How can a placenta turn hostile to the mother or fetus ? What are the abnormalities found during placental delivery ?
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31 views

Is asexual and sexual reproduction a universal feature of Bryozoans?

I found some clues that most, if not all, bryozoans can reproduce and multiply by asexual and sexual means, for example: Thomsen & Hakansson 1995: "Sexual Versus Asexual Dispersal in Clonal ...
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110 views

The probability of indirect human fertilization (follow-up)

This question is a follow-up to this one. I've been wondering how small that probability is. As we all know, "safe" sex, that is (correctly) using a condom and all that, isn't perfectly safe. So, in ...
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Meiosis I or II [closed]

Suppose an organism has 8 chromosomes. When the female and male organisms mate, how many chromosomes will the mother contribute to the offspring? Why?