Term
| Explain some of the mechanisms by which animals clone themselves. Give some examples. |
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Definition
budding=an offspring begins to form within or on a parent, and it eventually breaks free ( cnidarians)
Fision/fragmentation=an individual splits into 2 or 3 descendants (planarians)
Regeneration= recreating whole body parts or the entire organism (echinoderms)
Parthenogenesis= female offspring develop from unfertilized eggs (bees, whip-tail lizards) |
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Term
How is parthenogenesis fundamentally different from other cloning methods? What does it mean that it can be
facultative? |
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Definition
the other cloning methods don't produce eggs or anything, they just form off of the adult. parthenogenesis offspring come from unfertilized eggs produced by the mother.
facultative means that an organism can switch from one to the other. |
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Term
Describe some of the ways by which sex is determined. Under what circumstances is sex not permanently determined?
What happens when it isn’t? |
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Definition
1. the ratio of X to autosomes
2. presence or absence of a Y or W sex chromosome
3. temperature
4. environment
5. need
6. desire
7. location
8. genetics
it is not permanent when the organism is facultative so that the organism can switch to different types of reproduction. |
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Term
Under what conditions is external fertilization possible or even desirable? Under what conditions is internal fertilization
essentially necessary? |
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Definition
almost all organisms in aquatic environments use external fertilization
internal fertilization allows transfer of sperm in dry conditions |
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Term
| Other than mechanical considerations, how do the requirements of external versus internal fertilization strategies differ? |
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Definition
in external fertilization, the organisms release vast numbers of gametes to increase the odds of success, and simultaneous release is important and this is controlled by pheromones. gametes look for eachother
In internal fertilization, less male gametes are released and they are deposited into the female to try to fertilize a few number of female gametes. gametes don't need to look for eachother |
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Term
| Describe some strategies animals utilizing internal fertilization use for transferring sperm from male to female. |
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Definition
| sperm can be packaged for delivery to the female in sperm packets with either the male or female deposits, to the sperm can be deposited directly into the female by the male usually by a copulation organ. |
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Term
Female humans have little control over what sperm from multiple matings will fertilize the egg. How is that different in
some other animals? |
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Definition
| it some species the female exercises control over which sperm she uses. they can actively choose which male performs the last copulation before fertilization takes place. In other species the females can physically eject sperm from undesirable males. |
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Term
| Of what use are the seminal vesicles and prostate gland? |
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Definition
they both produce the accessory fluids that are added to the sperm to make semen.
seminal= sugar and prostaglandins
prostate= citric acid and antibiotic |
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Term
| What is a baculum? Where is it found? What is a baubellum? Where is it found? |
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Definition
baculum= a bone inside of their penis for quick sex so they can achieve an erection in time.
baubellum= female equivalent to a baculum |
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Term
| About how many eggs are produced per day in humans? When are they produced? Where are they stored? |
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Definition
none
they are produced in fetal development
ovary |
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Term
| How does reproduction in reptiles and birds differ from mammalian reproduction? |
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Definition
reptiles= egg travels down the oviduct. becomes fertilized and albumin is added, and then a shell forms and the shell passes out of the vagina, out of the system. they lay eggs with a yolk and the embryo develops inside.
mammalian= eggs pass down the oviduct (Fallopian tube) and if they are fertilized they are transported to the uterus. where the embryo grows until it is time for birth when the offspring pass out of the mother through the cervix and then the vagina.
the embryo develops inside the uterus and is born live. |
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Term
Differentiate between a primary oocyte and a secondary oocyte. Where specifically are they found? What happens to a
secondary oocyte? What happens to what it is in, in the short term? |
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Definition
primary= the ones you are born with and develop into the second. one egg is developed in each ovary every cycle.
secondary=the eggs that are ovulated at the end of each cycle.
the follicle becomes the corpus luteum |
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Term
| What causes a follicle to grow? Where is the stimulus generated? |
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Definition
the follicle is stimulated to grow with the follicle stimulating hormone (FSH)
FSH is produced in the pituitary gland in the brain. |
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Term
| What two things are unusual about the regulation of luteinizing hormone? |
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Definition
| 1. regulated by estradiol by negative feedback in low concentrations and positive feedback in high concentrations. |
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Term
| Where is most of the progesterone produced? Is this the same place that most of the estradiol is produced? |
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Definition
the follicle produced estradiol
and the corpus luteum releases progesterone
kind of because the follicle becomes the corpus luteum in a later stage. |
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Term
| Under what conditions does the corpus luteum remain or not remain in the ovary? |
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Definition
if fertilization does not occur, the corpus luteum degenerates after about 12 days post-ovulation.
if fertilization does occur, the corpus luteum remains in the ovary to release progesterone |
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Term
| Where physically in mammals and reptiles does fertilization take place? |
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Definition
| fertilization takes places in the oviducts of both reptiles and mammals. |
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Term
| Why is the time span during which fertilization can take place in humans so short (it is not so in many other animals)? |
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Definition
| the egg only lives for one day and the sperm only live 5 days. |
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Term
| What is unusual about meiosis in mammalian (and especially human) female reproduction? |
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Definition
| it goes to 2nd metaphase two and then it will or will not be fertilized. |
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Term
| What is the purpose of the umbilical cord? |
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Definition
| connects embryo to the placenta and the mother. allows for oxygen and nutrients to get to the placenta and to the fetus through the mothers blood. |
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Term
| When is an embryo not an embryo any more? What is it? |
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Definition
| in the first trimester the embryo becomes a fetus after 8 weeks. |
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Term
| How are the second and third trimesters of pregnancy fundamentally different from the first trimester? |
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Definition
the first trimester is development and forming the needed organs and tissues.
the second and third trimesters are needed for growth and development. |
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Term
Why must the mother’s breathing, heart rate, etc. increase by 50% even tho the fetus never gets to be more than 10% of
her weight? |
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Definition
| the fetus has a higher demand for oxygen because the organs are developing and it is growing, and not just maintainence. |
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Term
Why is a menstrual cycle approximately 28 days? During which days (which numbers?) is intercourse most likely to
lead to pregnancy? Why? |
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Definition
the first cycle is the follicular phase which lasts 14 days. after this stage is the luteal stage which is also 14 days. when added together it is 28 days.
during days 9 and 15 because the sperm live for 5 days before ovulation and the egg lives for one day so 6 days total |
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Term
| Why do parthenogenic species generally consist solely of females? |
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Definition
| because the female offspring lay unfertilized eggs which then develop into more females. they have no way of developing males unless they use a different type of reproduction. |
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