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ZygoteA fertilized egg.
AcrosomeA little sac at the head of a sperm. It is filled with enzymes that help the sperm get into an egg, like its own personal safe-cracking kit.
AllelesDifferent flavors of a gene, like brown eyes or blue eyes.
AllantoisSpecial embryonic membrane in amniotic egg. Important for gas exchange.
AmnionSpecial embryonic membrane in an amniotic egg that directly surrounds the embryo/fetus. Filled with amniotic fluid. Makes the womb like a big water balloon.
AmniotesBirds, reptiles, and mammals. Their eggs require special membranes because they develop on land.
AnamniotesFish and amphibians. Their eggs develop in the water with only a simple embryonic membrane.
Asexual ReproductionOne parent required to reproduce. Nothing sexy about it.
Biological ImperativeThe driving force to reproduce. It is almost like every animal is under a witch's spell to make more animals.
Blocks To PolyspermyThings that happen to prevent an egg from being fertilized by more than one sperm. The egg doesn't have a bouncer at the door, so it uses other methods to get rid of extra sperm.
Blastocyst (or Blastula)Stage of embryo development where cells form a hollow ball. Almost like somebody blasted out the middle.
BuddingType of asexual reproduction where new animals grow like a blob on a parent and then split off
ChorionSpecial embryonic membrane in amniotes. Surrounds amniotic sac, allantois, and yolk sac. Lies just beneath the egg shell.
ChromosomeLong segment of condensed DNA consisting of many genes
CloacaAn opening used for both reproduction and waste removal. Found in birds, reptiles, amphibians, and monotremes. You never know what is going to come out of this hole.
CopulationThe act of physically bringing together the sex organs (for example, penis, cloaca, or vagina) for gamete release. The cops can't stop these gametes from getting together.
CoitusSame as copulation.
CourtshipFinding and wooing a mate.
Courtship RitualSpecial behavior to communicate interest to a potential mate. Special dance moves, tail waggles, sniffing urine, etc.
DiploidA cell with two versions of every chromosome. This usually means one from the mother and one from the father.
EctodermOne of the germ layers formed in gastrulation. It will form outer things like skin, hair, and teeth. It also forms the nervous system.
EndodermOne of the germ layers formed in gastrulation. It will form most of the organs.
EggThe female gamete, also called an oocyte. It can also mean the full structure that the oviparous embryo develops in, like a hard bird or reptile egg.
Egg ToothA tiny nub of hard deposit usually found on a baby bird's beak. It is used to break out of the egg. It usually falls off after hatching.
EjaculateThe act of a male releasing his sperm.
Estrous CycleThe hormone cycle that controls a female's gamete production. Some mammals have a menstrual cycle instead.
External FertilizationUnion of sperm and egg that occurs outside the body in the environment. Some fish could probably sell tickets to this event.
FertilizationUnion of sperm and egg. That glorious moment when the gametes first meet.
FissionType of asexual reproduction where the animal splits in half (or sometimes more parts).
FlagellaThe whip-like tail that a sperm has. This powerful engine propels the sperm over huge distances.
FollicleLocated in the ovary. Each follicle contains a single primary oocyte.
GameteThe happy haploid cells produced for sexual reproduction. Sperm and Eggs.
GastrulaA stage of embryo development where the blastocyst differentiates and the cells are not identical anymore.
GastrulationThe process of differentiation where cells change into three different types of germ layers: ectoderm, endoderm, mesoderm. Each layer will develop into different types of tissue (and we don't mean Kleenex or Puffs).
GeneSection of DNA that codes for a particular protein. For example, a gene for eye pigment determines your eye color. In reality, eye color is controlled by more than one gene, but let's keep it simple.
GenomeThe collection of all your genes. It is a priceless one of a kind collection, unless you have an identical twin.
Germ CellsThe pre-gamete cells. Before they were sperm and eggs they were spermatogonia and oogonia.
Germ LayersThe first cells in an embryo that have a destiny. The three layers: ectoderm, endoderm, and mesoderm each have a different future.
HaploidA cell with only one version of every chromosome. Gametes are haploid.
HaremA group of females controlled by one male, who has exclusive mating rights among those females.
HermaphroditeAn animal that can make both the male and female gametes. A Jack/Jill of all trades.
Internal FertilizationUnion of the sperm and eggs that takes place inside the mother. How hospitable.
Intersexual SelectionMate selection where males and females are involved in selection. Usually one sex is choosy, and the other sex shows off.
Intrasexual SelectionMate selection where males compete with males (or females compete with females). The other sex is usually just a super awesome amazing prize.
IteroparityWhen an animal can reproduce more than once in its lifetime. They are doing "it" a lot.
LaborThe process of giving birth in viviparous animals like mammals.
Law Of Independent AssortmentSays that during meiosis each chromosome gets sorted into the 4 haploid gametes independently of the other chromosomes. So, a single gamete could have the maternal OR paternal version of chromosome 1 and the maternal OR paternal version of chromosome 2. The manager of giving out versions of chromosome 1 does not consult the manager of chromosome 2.
Law Of Independent SegregationSays that each gamete only gets one version of each chromosome, either the maternal or the paternal version. This is obvious if you remember that gametes are haploid (and remember what haploid is).
Leydig CellsCells in the testes which secrete hormones during sperm production. Ooh ley ley.
MarsupialsA special type of mammal that delivers undeveloped young and then carries them in a pouch for further development. Kangaroos and Koala bears are marsupials.
MateA partner for sexual reproduction.
MatingThe process of sharing gametes in sexual reproduction. The conversation probably goes like this: "So, I'll provide the 30 million sperm, and you provide the one egg."
MatriphagyWhen children eat their (hopefully delicious and nutritious) mother. This has been well-studied in spiders.
MeiosisThe process of making 1 diploid cell into 4 haploid gametes. A genome replication followed by two splits.
Menstrual CycleThe cycle of hormones which controls the build-up of the uterine lining. If an egg is not implanted, the endometrium is too sad to continue. It is then excreted from the body.
MesodermOne of the germ layers. These cells will turn into muscle, blood vessels, and connective tissue.
MonogamousOnly having one mate. The old ball and chain could be around for one mating season or for their entire life.
MonotremesSpecial type of mammals that lay eggs, like the platypus.
MorulaStage of embryo development where the solid ball of cells look like a raspberry. This is right before they become a hollow blastocyst.
OocyteThe female gamete. Also called an egg.
OogenesisThe process of producing the female gametes.
OvariesThe female organ where oogenesis takes place.
OvoviviparityAn animal that develops in an egg (and gets nutrition only from the egg), but the egg is inside one of the parents and not in the environment.
OviparityAn animal that develops in an egg that is out in the environment. Birds, reptiles, most fish, amphibians, and monotremes are oviparous.
OvulationWhen a female shoots an egg out of her ovary.
ParthenogenesisA virgin birth where the reproduction occurs even though the female egg has not been fertilized.
ParturitionThe process of giving birth. We bet many moms wish they just had an ejector seat button.
PenisThe male accessory sex organ used to deposit sperm inside a female for internal fertilization.
PheromonesChemicals that are released by some animals, often as a part of a courtship ritual. Mmm, smells like someone is available.
PlacentaThe connection between mother and fetus in mammals through which the fetus gets nutrition and gas and waste exchange.
Polar BodyThe smaller cell formed in both the meiotic divisions of oogenesis. Only 1 of the 4 haploid cells created will become an oocyte. The others are polar bodies and will deteriorate.
PolygamousHaving more than one mate.
Primary OocyteThe oocyte in arrest from birth until puberty. It will eventually undergo the first division of meiosis. Are they lazy or just very patient?
Primitive StreakA section of cells formed early in gastrulation which makes the egg asymmetrical and provides the first bit or organization during gastrulation.
RecombinationThe process during meiosis where of bits of maternal and paternal chromosomes swap chunks of DNA.
RegenerationA type of asexual reproduction where an animal can re-grow after part of it is removed. Perhaps vampires heal in a similar way.
Secondary OocyteThe large cell after the first meiotic division of oogenesis that can be fertilized.
SemelparityWhen an animal only reproduces one time in its life. Big-bang reproduction.
Seminiferous TubulesThe part of the testes where spermatogenesis party takes place.
Sexual DimorphismA difference between males and females. Size, color, strength, etc.
Sexual ReproductionReproduction requiring the union of sperm and egg.
SpawningProcess of fish and amphibians releasing their gametes into the water for external fertilization. Have you ever seen a fish yawning while spawning?
SpermatogoniaThe pre-sperm germ cells. They will become sperm at the end of spermatogenesis.
Spermatozoa (Sperm)The male gamete.
SpermatogenesisThe process of making sperm. There is a blue ribbon recipe in the Testicular Cookbook.
Testicles (Testes)The male sex organ where sperm are produced.
Umbilical CordThe cord that plugs the fetus into the placenta. Have you ever heard of cutting the cord? Yep, this is the one.
VaginaA female orifice only used for reproduction.
ViviparityWhen animals give live birth. Mammals are viviparous.
YolksacA source of nutrition inside an egg. The yellow part inside a chicken egg is the yolk.
ZygoteA fertilized egg.
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