Intro to Reproduction Flashcards
What is taxonomy?
study box the principles of scientific classification; systematic ordering and naming of organisms
What is phylogeny?
the evolutionary history of the origin and diversification of any taxon, usually presented in the form of a dendrogram. The one true tree of life
What is cladistics?
an approach or methodology for classifying organisms based on common evolutionary descent
What are the 2 types of reproduction?
sexual
asexual
What is sexual reproduction?
- fusion of two specialized cells, or gametes
- generally involves two parents
- most common strategy in vertebrates
- sexual reproduction recombines parental characters (results in a more diverse population)
What are the advantages to sexual reproduction?
- debated (several theories)
- ability to mix and match successful genes (more rare or novel genotypes)
What are the disadvantages to sexual reproduction?
- energetically costly
- males do not directly produce offspring
What is asexual reproduction?
- involves only one parent
- no special reproductive organs or cells (no formation of gametes)
- produces genetically identical offspring (clones)
- widespread in bacteria, unicellular eukaryotes, and many invertebrates
- rare among vertebrates
What are the advantages of asexual reproduction?
- quick and energy efficient
What are the disadvantages of asexual reproduction?
- phenotypic diversity depends on mutation
- they can’t produce a genome with less deleterious mutations than the parent
What are the types of asexual reproduction?
1) Binary fission
2) Multiple fission
3) Budding
4) Gemmulation
5) Fragmentation
What is binary fission?
- common among bacteria and protozoa
- the parent divides by mitosis into two parts
- each grows into an individual similar to the parent
What is multiple fission or Schizogony?
- nucleus divides repeatedly
- cytoplasmic division then produces many daughter cells simultaneously
What is budding?
- unequal division of an organism
- bud is an outgrowth of the parent
- develops organs and then detaches
What is gemmulation?
- formation of a new individual from an aggregation of cells
- cells are surrounded by a resistant capsule (a gemmule)
What is fragmentation?
- like binary fission for multicellular animals
- breaks into two or more fragments that become a new individual
different from budding because each fragment grows new parts
What are the types of sexual reproduction?
1) Bisexual reproduction
2) Hermaphroditism
3) Parthenogenesis
What is bisexual reproduction?
- most common form
- male and female gametes (sperm or egg) are produced
- two haploid (n) gametes combine to form a zygote (2n)
What is hermaphroditism?
- male and female organs occur in same individual
- most avoid self-fertilization
What is parthenogenesis?
- embryo develops from unfertilized egg
- sperm may activate but not fuse with egg
What is dioecious?
- having male and female gonads in separate individuals
- nearly all vertebrates and many invertebrates
What is monoecious?
- having both male and female gonads in the same organism (hermaphroditic)
- many sessile, burrowing invertebrates are hermaphroditic (some vertebrates and most avoid self-fertilization)
What is oviparous?
- reproduction in which eggs are released by the female
- development of offspring occurs outside the maternal body
- external or internal fertilization
What is viviparous?
- reproduction in which eggs develop within the female body, which provides nutritional aid
- internal fertilization
What is ovoviviparous?
- reproduction in which eggs develop within the maternal body without additional nourishment from the parent
- hatch within the parent or immediately after laying
- internal fertilization
- derive nourishment from yolk, not from mother
