Animals Theme 5 Flashcards
What form of reproduction occurs when an organism splits into 2 different offspring that are genetically identical
Fission/Asexual
What form of reproduction occurs when the offspring grows attached to a parent and splits off at maturity
budding/asexual
What is fragmentation?
piece of an organism is separated and becomes a new individual (asexual)
What is the process of developing from an unfertilized egg?
Parthenogenesis (asexual)
What are the pros and cons of asexual reproduction
Pros: reproduce in isolation, reproduce rapidly. Cons: no genetic variablilty
What are the male and female gametes and their process of development
Sperm (spermatogenesis), Egg (oogenesis)
What is dioecious
Having the male and female reproductive organs in separate individuals
What is monoecious? And what are the two types?
Having both male and female reproductive organs in the same individual. Simultaneous (always both) and sequential (switch between)
What are the pros and cons of sexual reproduction?
Pros: genetic variability. Cons: more complex, slower
The acrosome on a sperm
is the cap of nucleus and helps sperm attach to egg
What are the characteristics of external fertilization?
Release sperm into environment, many gametes, and small
What are the characteristics of internal fertilization
Male deposits sperm into female, mating behavior and competition
Fusion of the egg and sperm release Ca to trigger a cortical reaction, coating the egg and preventing other sperm to penetrate into the egg
Slow block polyspermy (minutes)
Fusion of the egg and sperm triggers depolarization which alters the egg plasma membrane, preventing other sperm to fuse with the egg.
Fast block (seconds)
Egg-bearing reproductive systems
Oviparous
retain embryo in mothers body
Viviparous
Retaining fertilized eggs in the body of the mother, and the egg has internal fluids for nutrients
Ovoviviporous
Which organisms are oviparous?
reptiles and insects
which organisms are viviparous?
mammals
which organisms are ovoviviparous
fish, lizards, and sharks
which organisms are ovoviviparous
fish, lizards, and sharks
What is the order of early development (Ontogeny)
Fertilization, Cleavage, Gastrulation, Organogenesis, and metamorphosis
a sperm penetrates an egg and their nuclei fuse to produce a zygote
Fertilization
Mitotic division produces a morula composed of blastomeres, and after further division produces a blastula
Cleavage
Cell division, migration and rearrangements produce a gastrula (embryo that has primary tissue layers)
Gastrulation
cellular mechanisms produce major tissue and organs in embryo development, the organization characteristics of the species emerge
Organogenesis
The stage when the animal develops into an adult, and all tissues and organs carry out their specialized functions
metamorphosis
What is direct development?
The youth is the smaller version of an adult
what is indirect development?
The youth is in a different form than the adult
What are the characteristics of the animal poles in cleavage
gives rise to the surface structures and anterior end of the embryo
What are the characteristics of the vegetal pole in cleavage
larger cells, that provide nutrients for the fetus, and give rise to internal structures like the gut. On the posterior end of the embryo
In what stage does the formation of the ecto-/meso-/endoderm form
Gastrulation
What are the 6 mechanisms of gastrulation
Mitosis, cell movement, selective cell adhesion, induction, determination, and differentiation
What is induction in gastrulation?
A group of cells influences another group of cells to follow a particular developmental pathway
What is cell determination?
When the developmental fate of the cell is determined, usually due to induction
What is differentiation in gastrulation?
When the cells actually become specific tissues
Sea urchin gastrulation
invagination in the vegetal pole leads to the endoderm-lined cavity with the mesoderm formed between the endo-/ectoderms
Frog gastrulation
Cells from the animal pole reach the dorsal lip and invaginate. Cells migrate into blastopore (involution). Archenteron (beginning of the gut) form
What is Neurulation?
the development of neural tissue in the ectoderm
What is the significance of Neural crest cells
The neural crest cells are able to migrate throughout the embryo after the neural tube is formed to become numerous different cell types
What does the neural tube become
brain and spinal cord and central nervous system
