Animal Reproductive Development Flashcards
What are features that define an animal?
multicellular, heterotrophic eukaryotes that mostly obtain nutrients by ingestion
no cell walls
muscle cells and nerve cells
cell junctions
What are the cell junctions unique to animals?
tight junctions and gap junctions
What are tight junctions?
bind epithelial and endothelial cells tightly together (variety of functions incl. acting as a primary barrier to the diffusion of solutes through intracellular space
What are gap junctions?
channels that physically connect adjacent cells mediating the rapid exchange of small molecules between cells
Describe the life cycle of most animals by sexual reproduction
dominant diploid adult that produces haploid eggs or sperm by meiosis.
gametes fuse to form a diploid zygote
zygote passes through a series of distinct embryonic stages, developing in the adult animal
What are the 4 types of asexual reproduction? which ones do some animals do?
animals:
parthogenesis
budding
fragmentation
not animals;
binary fision
What is Binary fission?
a form of cell division in which the genome replicates and the cell divides into two cells (prokaryotes)
What is budding?
a bud, or protrusion, forms on an organism and eventually brekas off to form a new organism that is smaller than its parent
What is Fragmentation?
new individuals arise by the splitting of one organism into two or more species, each of which develops into a new individual
What is Parthogenesis?
females produce eggs that are not fertilized by males; divide by mitosis and develop into new individuals
What is an example of parthogenesis?
asexual, all-female whiptale lizard (Cnemidophorus neomexicanus)
begisn with a simulated mating ritual in which the females bite and mount each other, so they lay unfertilized eggs, young hatch and are genetic clones of their mothers
What is an example of an animal that can undergo both sexual and asexual reproduction?
Daphnia
What is cleavage (post fertilization step)?
single-celled zygote divides by mitosis - resulting in many smaller cells in a solid ball called a morula
What is the blastula?
later embryonic stage - hollow ball o cells
What is a gastrula?
a saclike embryo with one opening - blastopore - and at least two layers of cells
What are the stages in a embryo development?
zygote, eight-cell stage, blastula, gastrula
What usually happens to the gastrula?
develops into one or more immature stages (e.g. larvae) that later develop into the sexually mature adults after metamorphosis
what is gastrulation?
coordinated set of movement sin which the cells of the blastoderm migrate inward, creating germ layers of cells within the embryo and ancheteron
what is the archenteron?
rudimentary alimentary cavity (‘gut’) of an embryo at the gastrula stage
what are germ layers?
primary layers tha forms during embryonic development
What is the ectoderm?
surface of the embryo forms the nervous system and outer surfaces such as skin, pigment cells and hair cells
What are the two types of germ layer?
ectoderm and endoderm
What is the endoderm?
inner most germ later, forms the respiratory and digestive tracts, as well as associated organs such as the liver and pancreas
how many germ layers do most animals have? called?
3 (bilaterians) called triploblastic
How many germ layers do cnidarians have? called?
2 called diploblastic
What is the mesoderm?
germ layer between the ectoderm and the endoderm forms majority of body organs, including muscle =, blood vessels, kidney, heart and skeleton
What are homeobox genes?
a group of genes that are involved in the regulation of patterns of anatomical embryonic development in multicellular organisms
