4h Flashcards
Define asexual and sexual reproduction; list examples of asexual reproduction (e.g. budding, fission, parthenogenesis)
Asexual - production through mitotic cell division, the offspring will be genetically identical.
Budding (sponges and cnidarians grow offspring on their body until developed, then they separate
Fragmentation (corals, jellies, brittle stars) body part to removed and them regenerated into two lill guys
Parthenogenesis eggs can develop without fertilisation (honey bees)
Sexual - unity of egg and sperm (haploid) to create a diploid cell, created genetic variation
List the reproductive organs responsible for producing eggs and sperm; define fertilisation, zygote, and hermaphrodite
What produces egg and sperm
Male gonads are the testis
Female gonads are the egg
Fertilisation - union of sperm and egg to form a zygote.
Zygote - forms from two haploid cell (egg and sperm) to make a diploid cell
Hermaphrodite - same individual can produce both sperm and the egg
Describe the various types of fertilisation methods found in the animal world, and the need for timing of ovulation for successful internal fertilisation
Internal fertilisation - copulation when direct placement of the sperm into the females bodies
External fertilisation - eggs and sperm are released into water based on the environmental cues, like length of days and temperature.
Describe the process of spermatogenesis, including the role of spermatogonia, primary spermatocytes, secondary spermatocytes, and spermatids
Spermatogenesis is how sperm is formed from spermatogonium in the testis (seminiferous tubules) the spermatogonia (diploid) undergoes mitosis, one is kept in reserve and the other undergoes meiosis to create sperm with a range of genetic variation.
spermatogonium -> primary spermatocyte -> secondary -> spermatids -> sperm
Describe the morphology of a sperm cell, and the function of each part
Made from tail and head segments
Acrosome - on the tip of the head holds many enzymes to penetrate into the egg
Midpiece - hold mitochondria to aid movement
Flagellum - movemovent
Describe the process of oogenesis, including the role of oogonia, primary oocytes,
secondary oocytes, and polar bodies
Oogenesis is the process of which is egg if formed by undergoing mitosis and meiosis which only beings during puberty
Oogonia enlarges and differentiates (mitosis) into primary oocyte. Then hormones trigger meiosis 1 (menstrual cycle) which is when a secondary oocyte is formed as well as the polar body (ovulation). Finally these undergo meiosis 2 to form the egg.
Oogonium -> primary oocyte -> secondary oocyte / 1 polar body -> 1 egg / 3 polar body
List the fundamental processes underlying animal development; differentiate between indirect and direct development; define yolk, larva and metamorphosis
Individual cells multiply
Some of their daughter cell differentiate
As differentiation happens cell become organised to create an organism
Yolk - food reserve in eggs which nourishes the embryo before it hatches.
Larva - amphibians and invertebrates are often born as larva which is sexually immature until metamorphosis.
Direct development - offspring are similar to parents (newborns are large and require significant amount of food)
Indirect development - offspring look completely different of parents
Describe the process of animal development, using amphibians as a model system. Include definitions of zygote, cleavage, morula, blastula, gastrula, and blastopore, and describe the development and fate of the three main tissue types (endoderm, mesoderm, and ectoderm)
Zygote - large cell diploid formed from fusion of egg and sperm
Cleavage - mass cell division
Morula - solid ball of cells
Blastula - hollow segment inside the morula
Gastrula - gastrulation is the formation of the gastrula as the cells shift and reorgasine into their correct shape.
Blastopore - a dimple shaped into the cell which starts the gastrulation process.
Consider amphibians as an example of indirect development, being in as a tadpole and growing into a frog
