Midterm Flashcards
What is Asexual Reproduction?
Takes one organism to produce and pass on genetic material. 100% of genetic material is passed on, thus the offspring is a copy
- Animal example: Amoeba
What is Sexual Reproduction?
The union of egg and sperm. There needs to be a mating occurring and there is genetic variation (50%/50% per parent)
What is the Biological Paradigm?
The animal that leaves the most genes in the next generation, wins, immortality as in offspring
What is reproduction?
When animals (and plants) give rise to offspring which may consist of a portion of the parent by sexual or asexual reproduction
What is sex?
Reproduction marked by the union of gametes (male sperm, female egg).
However, reproduction can happen with union of gametes (sexual) or without union of gametes (asexual)
What are gonads? What are the male and female gonads?
Reproductive glands that produce “germ cells” which mature into “gametes”
Male gonads are tests (sperm are the gametes)
Female gonads are ovaries (eggs are the female gametes)
How do bacteria reproduce?
Through binary fission (asexual reproduction)
the bacterium grows large then the parent splits and becomes two equal parts
How can bacteria DNA be altered?
Conjugation…with “sex pillus” connector
Conjugation is NOT reproduction, bacteria aren’t replicated but altered
When was the first asexual reproduction?
3.8 billion years ago
When was the first sexual reproduction?
1.5 billion years ago
What species can produce sexually and asexually?
Green Algae
Due to environmental changes, “sex inducer gene” is turned on
What is a phenotype?
An organism’s outward appearance influenced by genes and the environment (the external)
What is a genotype?
An organism’s genetic make up (the internal)
How many chromosomes do humans have?
46 total, 23 pairs (including the 2 sex chromosome and 44 autosomes)
Does asexual reproduction use mitosis or meiosis?
Mitosis
Does sexual reproduction use mitosis or meiosis?
Meiosis
Why during the process of Meiosis is each sperm or egg different?
The process of “crossing over” where genetic material swapped and that causes genetic diversity
What can cause genetic variation?
I. Genetic recombination (crossing over)
II. Spontaneous Mutation, errors
III. Induced by external mutagen
What is genetic recombination (crossing over)?
Meiosis process where the child gets a trait (hair color for example) similar to one of their parents
What are spontaneous mutations?
Errors that occur during replication (extra chromosome - down syndrome)
What are external mutagens that can cause variation?
Radiation, smoking, pollution
What were Charles Darwin’s 5 points on Natural Selection?
- All individuals are born with slight variation
- Some variations are neutral, some deleterious, but some bestow an advantage
- Those animals with an advantage will breed more readily and pass on these advantageous variations
- Survival of the fittest
- Overtime, new species may arise due to variation
What are pros and cons of Asexual Reproduction?
Pro:
- fast and easy
- takes only 1 organism
Cons:
- no genetic variation
What are pros and cons of sexual Reproduction?
Pros:
- Offspring have genetic variation
Cons:
- not fast and easy
- needs a mate
What are genetics?
Genes (blueprint of inheritance)
What are genes?
A linear portion of DNA
A gene codes for a protein
What is a chromosome?
A long strand of DNA made up of many genes
What is Loci?
Known genes are found on a certain chromosome at a certain location or position
What is an allele?
An alternative form of a gene
What is Fertilization?
When specialized gametes (a haploid egg & haploid sperm) come together to form a (diploid) zygote
In humans, which is more expensive egg or sperm?
Egg!
What are polar bodies?
When eggs divide unevenly, and more cytoplasm is placed in a daughter cell. Smaller eggs are known as polar bodies
What are the steps of mammalian fertilization?
- Ovary releases egg
- Egg and sperm meet
- egg travels to fallopian tubes
- Implanted in uterus
How long after egg release, does the egg need to be fertilized? How long can sperm live in a woman’s reproductive tract?
- 12-24 hours
- 5 days
About how many eggs do human females hold?
1-2 million where with each egg loss, the quality of egg decreases
How much sperm do men reproduce?
360 trillion, as of recent times, the quality of male sperm has decreased
What caused the decline in quality of human eggs and sperm?
Mutation
True or false: Even when women go through menopause, men can still produce sperm that can cause pregnancy?
True!
True or false: In meiosis, more sperm is produced than eggs?
True!
True or false: In mammals, females typically produce more offspring than males
False, males typically produce more offspring
True of False: the female track can weed out inferior sperm?
True!
What is the “passive egg fallacy”?
Contradicts the idea that the sperm is the ‘key’ to the egg’s ‘lock’
truth: the egg is in control in choosing which sperm fertilizes the egg
What is external fertilization? What is a species that engages on external fertilization?
When gametes unite outside the female’s reproductive tract
fish! they drop their eggs outside, and a male will come over on top the eggs and release his sperm thus fertilizing the eggs
What are pros and cons for external fertilization?
pros:
- doesn’t have to carry eggs
- may or may not have parental care
- self sufficient
- can have high rates of dispersal
cons:
- many eggs aren’t fertilized
- many eggs are wasted as they are eaten
- dispersed to inappropriate habitats
- need to find water (if amphibians)
- doesn’t know father
What is internal fertilization?
Gametes unite within the body of the inseminated animal (typically in the females)
What insects mate in the air via internal fertilization?
Dragonflies, Lovebugs, Hoverflies
Is a female insect collecting a spermatophore considered internal or external fertilization?
Internal fertilization
Can males species get pregnant?
In the case of seahorses, Yes! the males carry the eggs once the female releases them into the male
What are the pros and cons of internal fertilization?
pros:
- Protected inside female (or male)
- Nutrition more constant
- can know relatedness (maternity & paternity)
- Can place eggs in safe setting
cons:
- highly dependent offspring
- females can be slowed down
What are some dangers of mating?
- can be preoccupied with mating and get hunted (male praire dogs)
- male-male contests (fights between males)
- males can hurt/kill the females (male mallards often drown females)
How is sex determined in birds? Name the chromosome type and which sex determines the offspring sex
ZZ males, ZW females
females decide the sex
How is sex determined in most insect? Name the chromosome type and which sex determines the offspring sex
XY males, XX females
male decide the sex
How is sex determined in grasshoppers and crickets? Name the chromosome type and which sex determines the offspring sex
XO males, XX females
males decide the sex
How is sex determined in butterflies? Name the chromosome type and which sex determines the offspring sex
WW male, WZ female
female decide the sex
What are secondary sex characteristics? and name some
traits that appear during puberty
(breasts, facial hair, muscle mass)
What are primary sex characteristics?
gonads and any anatomical part of internal reproductive system
(penis&balls, vagina)
What are the male and female sex hormones?
Female: Estrogens
Male: Androgens
True of false: sex hormones are synthesized from cholesterol
True!
T or F: Sex hormones are excreted by endocrine glands
True! (through the testes, ovaries, and adrenal)
T or F: Sex hormones controls puberty & reproduction
True!
Where do females produce testosterone?
In the ovaries and adrenal gland
Where do males produce estrogen?
in the adrenal glad
What does estrogen regulate in females?
Regulates secondary sex characteristics:
pubic hair, breasts, menstrual cycle
What does progesterone do?
Regulates menstrual cycle, pregnancy, and growth of the embryo
T or F: Prolactin is a sex hormone
False! but high levels can decrease levels of certain sex hormones
What does prolactin do?
related to maternal care including mammalian milk
regulates the immune system and overall metabolism
What are some male secondary sex characteristics?
deepening of voice, muscles mass, growth spurts, increased energy
T or F: testosterone can improve muscle mass and stamina
True! it is produced endogenously by the body in the male testes (inside the body)
What is called when you have artificial testosterone?
Exogenous testosterone (made outside the body)
What are some negatives of artificial testosterone and other steriods?
- hurt the kidney’s
- hurts your liver
- ligaments and joints degrade
- lower sperm count
T or F: for endogenous testosterone, can heighten sex drive but does not correlate with sex drive
True! sex drive is correlated with external stimulus rather than testosterone
What is the “fragile male” concept?
Name the 3 sources
Developing males are more difficult than females
- more spontaneous abortion, hemorrhaging
- male brain at birth is heavier, more risks with oxygen loss at birth
- more congenital deformities (heart defects)
T or F: baby girls suffer more genetic disorders than males
False! baby boys are more prone to genetic disorders
What are some reasons for the sex ratios to shift?
smoking, pesticides
What is fitness in biology?
the extent to which an organism is adapted to, or is able to produce offspring in a particular environment