Quote:
a) A parasite is defined as an organism of one species living in or on an organism of another species (a heterospecific relationship) and deriving its nourishment from the host (is metabolically dependent on the host). (See Cheng, T.C., General Parasitology, p. 7, 1973.)
b) A human embryo or fetus is an organism of one species (Homo sapiens) living in the uterine cavity of an organism of the same species (Homo sapiens) and deriving its nourishment from the mother (is metabolically dependent on the mother). This homospecific relationship is an obligatory dependent relationship, but not a parasitic relationship.
All I have to say is...O RLY?
Here's the relevant part of that excerpt:
"Microplitis croceipes (Hymenoptera: Braconidae) is a larval parasitoid of Helicoverpa/Heliothis spp. In the course of mass rearing of M. croceipes, we found that females oviposited in the conspecific adults in rearing cages..."
There you go, undeniable parasitism occurring between members of the same species. Granted, the parasite offspring did not progress very far but all that shows is that evolution has developed safeguards within species to help prevent or discourage conspecific parasitism, not that parasitism cannot, by definition, occur between members of the same species.
Quote:
a) A parasite is an invading organism -- coming to parasitize the host from an outside source.
b) A human embryo or fetus is formed from a fertilized egg -- the egg coming from an inside source, being formed in the ovary of the mother from where it moves into the oviduct where it may be fertilized to form the zygote -- the first cell of the new human being.
b) A human embryo or fetus is formed from a fertilized egg -- the egg coming from an inside source, being formed in the ovary of the mother from where it moves into the oviduct where it may be fertilized to form the zygote -- the first cell of the new human being.
I don't know that anyone really debates this particular point (though to be fair, I see rather a lot more of you harping on the idea that 'parasites cannot be of the same species than I do people arguing that a parasite must be 'invasive')
Quote:
a) A parasite is generally harmful to some degree to the host that is harboring the parasite.
b) A human embryo or fetus developing in the uterine cavity does not usually cause harm to the mother, although it may if proper nutrition and care is not maintained by the mother.
b) A human embryo or fetus developing in the uterine cavity does not usually cause harm to the mother, although it may if proper nutrition and care is not maintained by the mother.
Ah, the weasel wording begins. Count to see, from now on, how many times you see the words 'generally', 'usually', 'normally', 'in rare instances' et cetera, et cetera, et cetera.
In any case, here's the standard Talon/Moni response to the idea that fetuses do not cause 'harm' to their mothers
Talon/Moni's giant ******** list of pregnancy related side-effects
Pregnancy and Childbirth complications are the number one killer of women ages 15-44 worldwide.
These are the normal, frequent or expectable temporary side effects of pregnancy:
-- exhaustion (weariness common from first weeks)
-- altered appetite and senses of taste and smell
-- nausea and vomiting (50% of women, first trimester)
-- heartburn and indigestion
-- constipation
-- weight gain
-- dizziness and light-headedness
-- bloating, swelling, fluid retention
-- hemmorhoids
-- abdominal cramps
-- yeast infections
-- congested, bloody nose
-- acne and mild skin disorders
-- skin discoloration (chloasma, face and abdomen)
-- mild to severe backache and strain
-- increased headaches
-- difficulty sleeping, and discomfort while sleeping
-- increased urination and incontinence
-- bleeding gums
-- pica
-- breast pain and discharge
-- swelling of joints, leg cramps, joint pain
-- difficulty sitting, standing in later pregnancy
-- inability to take regular medications
-- shortness of breath
-- higher blood pressure
-- hair loss
-- tendency to anemia
-- curtailment of ability to participate in some sports and activities
-- infection including from serious and potentially fatal disease (pregnant women are immune suppressed compared with non-pregnant women, and are more susceptible to fungal and certain other diseases)
-- extreme pain on delivery
-- hormonal mood changes, including normal post-partum depression
-- continued post-partum exhaustion and recovery period (exacerbated if a c-section -- major surgery -- is required, sometimes taking up to a full year to fully recover)
These are the normal, expectable, or frequent PERMANENT side effects of pregnancy:
-- stretch marks (worse in younger women)
-- loose skin
-- permanent weight gain or redistribution
-- abdominal and vaginal muscle weakness
-- pelvic floor disorder (occurring in as many as 35% of middle-aged former child-bearers and 50% of elderly former child-bearers, associated with urinary and rectal incontinence, discomfort and reduced quality of life)
-- changes to breasts
-- varicose veins
-- scarring from episiotomy or c-section
-- other permanent aesthetic changes to the body (all of these are downplayed by women, because the culture values youth and beauty)
-- increased proclivity for hemmorhoids
-- loss of dental and bone calcium (cavities and osteoporosis)
These are the occasional complications and side effects:
-- hyperemesis gravidarum
-- temporary and permanent injury to back
-- severe scarring requiring later surgery (especially after additional pregnancies)
-- dropped (prolapsed) uterus (especially after additional pregnancies, and other pelvic floor weaknesses -- 11% of women, including cystocele, rectocele, and enterocele)
-- pre-eclampsia (edema and hypertension, the most common complication of pregnancy, associated with eclampsia, and affecting 7 - 10% of pregnancies)
-- eclampsia (convulsions, coma during pregnancy or labor, high risk of death)
-- gestational diabetes
-- placenta previa
-- anemia (which can be life-threatening)
-- thrombocytopenic purpura
-- severe cramping
-- embolism (blood clots)
-- medical disability requiring full bed rest (frequently ordered during part of many pregnancies varying from days to months for health of either mother or baby)
-- diastasis recti, also torn abdominal muscles
-- mitral valve stenosis (most common cardiac complication)
-- serious infection and disease (e.g. increased risk of tuberculosis)
-- hormonal imbalance
-- ectopic pregnancy (risk of death)
-- broken bones (ribcage, "tail bone" wink
-- hemorrhage and
-- numerous other complications of delivery
-- refractory gastroesophageal reflux disease
-- aggravation of pre-pregnancy diseases and conditions (e.g. epilepsy is present in .5% of pregnant women, and the pregnancy alters drug metabolism and treatment prospects all the while it increases the number and frequency of seizures)
-- severe post-partum depression and psychosis
-- research now indicates a possible link between ovarian cancer and female fertility treatments, including "egg harvesting" from infertile women and donors
-- research also now indicates correlations between lower breast cancer survival rates and proximity in time to onset of cancer of last pregnancy
-- research also indicates a correlation between having six or more pregnancies and a risk of coronary and cardiovascular disease
These are some less common (but serious) complications:
-- peripartum cardiomyopathy
-- cardiopulmonary arrest
-- magnesium toxicity
-- severe hypoxemia/acidosis
-- massive embolism
-- increased intracranial pressure, brainstem infarction
-- molar pregnancy, gestational trophoblastic disease (like a pregnancy-induced cancer)
-- malignant arrhythmia
-- circulatory collapse
-- placental abruption
-- obstetric fistula
And a few more permanent side effects:
-- future infertility
-- permanent disability
-- death.
In comparison, the normal side effects of tapeworm infestation are:
Abdominal discomfort
Diarrhea
Constipation
Weight loss
Would you like to tell me that, just based on the side effects, that the tapeworm, a parasite by any definition somehow meets the criteria for 'harm' more than a developing fetus does?
Quote:
a) A parasite makes direct contact with the host's tissues, often holding on by either mouth parts, hooks or suckers to the tissues involved (intestinal lining, lungs, connective tissue, etc.).
b) A human embryo or fetus makes direct contact with the uterine lining of the mother for only a short period of time. It soon becomes isolated inside its own amniotic sac, and from that point on makes indirect contact with the mother only by way of the umbilical cord and placenta.
b) A human embryo or fetus makes direct contact with the uterine lining of the mother for only a short period of time. It soon becomes isolated inside its own amniotic sac, and from that point on makes indirect contact with the mother only by way of the umbilical cord and placenta.
See again, what is probably the most blatant case of double-faced weasel wording and goalpost shifting in the entire list.
'Parasites generally make direct contact with the host's tissues and... well, fetuses do that too, but... LOOK, IT ONLY HAPPENS FOR A SET PERIOD OF TIME SO IT DOESN'T COUNT!'
Does that mean that encysted parasites are no longer parasites? After all, they only make direct contact for a short time before they're sealed off (whether by the host's immune response of through its own defensive actions).
Quote:
a) When a parasite invades host tissue, the host tissue will sometimes respond by forming a capsule (of connective tissue) to surround the parasite and cut it off from other surrounding tissue (examples would be Paragonimus westermani, lung fluke, or Oncocerca volvulus, a nematode worm causing cutaneous filariasis in the human).
b) When the human embryo or fetus attaches to and invades the lining tissue of the mother's uterus, the lining tissue responds by surrounding the human embryo and does not cut it off from the mother, but rather establishes a means of close contact (the placenta) between the mother and the new human being.
b) When the human embryo or fetus attaches to and invades the lining tissue of the mother's uterus, the lining tissue responds by surrounding the human embryo and does not cut it off from the mother, but rather establishes a means of close contact (the placenta) between the mother and the new human being.
More goalpost shifting. You cannot cite the absence of an event as evidence of your position when you yourself say that it is not a universal criterion. If this only sometimes (their word, mind you) happens, why is the fact that it doesn't happen with regards to fetuses evidence that they are not parasitic?
Quote:
a) When a parasite invades a host, the host will usually respond by forming antibodies in response to the somatic antigens (molecules comprising the body of the parasite) or metabolic antigens (molecules secreted or excreted by the parasite) of the parasite. Parasitism usually involves an immunological response on the part of the host. (See Cheng, T.C., General Parasitology, p. 8.)
b) New evidence, presented by Beer and Billingham in their article, "The Embryo as a Transplant" (Scientific American, April, 1974), indicates that the mother does react to the presence of the embryo by producing humoral antibodies, but they suggest that the trophoblast -- the jacket of cells surrounding the embryo -- blocks the action of these antibodies and therefore the embryo or fetus is not rejected. This reaction is unique to the embryo-mother relationship.
b) New evidence, presented by Beer and Billingham in their article, "The Embryo as a Transplant" (Scientific American, April, 1974), indicates that the mother does react to the presence of the embryo by producing humoral antibodies, but they suggest that the trophoblast -- the jacket of cells surrounding the embryo -- blocks the action of these antibodies and therefore the embryo or fetus is not rejected. This reaction is unique to the embryo-mother relationship.
Almost as bad as the 'direct contact with tissues' bit. 'Well, look, the mother does produce antibodies in response to the fetus' presence but, well, that's inconvenient to our point so we'll just disregard it.' There are many intestinal and blood-borne parasites that have their own (more or less) unique ways of ******** with the body's immune-response so why aren't they excluded based on this criterion?
Quote:
a) A parasite is generally detrimental to the reproductive capacity of the invaded host. The host may be weakened, diseased or killed by the parasite, thus reducing or eliminating the host's capacity to reproduce.
b) A human embryo or fetus is absolutely essential to the reproductive capacity of the involved mother (and species). The mother is usually not weakened, diseased or killed by the presence of the embryo or fetus, but rather is fully tolerant of this offspring which must begin his or her life in this intimate and highly specialized relationship with the mother.
b) A human embryo or fetus is absolutely essential to the reproductive capacity of the involved mother (and species). The mother is usually not weakened, diseased or killed by the presence of the embryo or fetus, but rather is fully tolerant of this offspring which must begin his or her life in this intimate and highly specialized relationship with the mother.
Childbirth remains the leading cause of death for women of childbearing age across the world. Unless I've missed something being dead is a fairly good way of negatively impacting the reproductive capacity of an individual.
Oh, and did you notice how they switched from talking about an individual in (a) to (primarily) about the species in (b)? Classy, that.
Quote:
a) A parasite is an organism that, once it invades the definitive host, will usually remain with host for life (as long as it or the host survives).
b) A human embryo or fetus has a temporary association with the mother, remaining only a number of months in the uterus.
b) A human embryo or fetus has a temporary association with the mother, remaining only a number of months in the uterus.
Yet more weasel words. 'Usually', 'often', 'commonly'. You cannot set non-universal criterion and then definitively exclude an organism based on the fact that it doesn't meet it. It doesn't work that way.
Quote:
A parasite is an organism that associates with the host in a negative, unhealthy and nonessential (nonessential to the host) manner which will often damage the host and detrimentally affect the procreative capacity of the host (and species).
A human embryo or fetus is a human being that associates with the mother in a positive, healthful essential manner necessary for the procreation of the species.
A human embryo or fetus is a human being that associates with the mother in a positive, healthful essential manner necessary for the procreation of the species.
Healthful? I'd like to see evidence that pregnancy and/or childbirth has net positive heath effects on the woman in question but regardless, here's another example of them trying to get away with comparing the effecting on an individual in section (a) and for the species as a whole in (b).
Now, just to diffuse any potential misunderstandings I'll say what I said to the person this was directed at:
"Now, I have to say, I don't think fetuses are literally parasitic, but I do think that pregnancy mimics the symptoms of parasitism to a surprisingly high degree, I mean, just look at all the knots your libertarians had to tie themselves in to get fetuses off the hook; "Parasites generally do this. Parasites usually do that. While fetuses meet this standard it doesn't count because...' "
Like I said, any critiques and additions would be most welcome.
