Lesson 6 - Reproduction And Development Flashcards
Two types of reproduction
- Asexual reproduction
- Sexual reproduction
Different types of asexual reproduction
- budding
- fragmentation
- binary fission
- parthenogenesis
- asexual reproduction method in which a new organism develops from a bud of an existing organism
- Until the new organism matures, it remains attached to the parent organism.
Budding
e.g. Budding
hydra
- fragment of the parent breaks off and develops into an entirely new but genetically identical individual.
- The parent will then regenerate, or regrow, the piece that broke off, so in the end there are two new individuals from one.
Fragmentation
e.g. Fragmentation
- flatworms
- starfish
- a separation of the body into two new bodies
- an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.
binary fission
e.g. binary fission
flatworms
asexual reproduction in which a female can produce an embryo without fertilizing an egg with sperm
Parthenogenesis
e.g. Parthenogenesis
arthropods
no. of chromosomes of male bee
haploid
no. of chromosomes of female bee
diploid
formed by parthenogenesis of queen bee
drone
formed by fertilization of gametes of bees
- worker sterile female
- queen
form of parthenogenesis in which unfertilized eggs develop into males.
arrhenotokous parthenogenesis
Different types of sexual reproduction
- external fertilization
- internal fertilization
- hermaphroditism
- sperm of a male creature fertilizes the egg of a female organism outside the female’s body
- external
External fertilization
- occurs when the sperm fertilizes the egg inside the female
- terrestrial
Internal fertilization
male and female gonads are present in one organism
hermaphroditism
e.g. external fertilization
echinoderms
e.g. internal fertilization
insects
e.g. hermaphroditism
earthworms
Types of hermaphroditism
- Simultaneous hermaphroditism
- Sequential hermaphroditism
when the same organism has both the male and female sex organs and produces both types of gametes.
Simultaneous hermaphroditism
an organism switches from its inborn sex to the opposite sex, a development observed primarily in certain fish and gastropods.
Sequential hermaphroditism
Types of Sequential hermaphroditism
- protandry
- protogyny
organism starts life as a male and later transforms into a female
protandry
e.g. protandry
- shrimp
- limpets
organism begins as a female and then changes into a male
protogyny
e.g. protogyny
- slugs
- oysters
- polychaetes
raised band encircling the body of oligochaete worms and some leeches, made up of reproductive segments
clitellum
Sexual Reproduction Processes
- sex determination
- gametogenesis
- reproductive timing
- mating behavior
- fertilization
- fecundity
- sex differentiation
- sex ratio
sex determination
- gamete quality
- composition
gametogenesis
- synchronization
- spawn timing
reproductive timing
- mate choice
- competition
mating behavior
- egg and sperm viability
- fertilization success
fertilization
- reproductive output
- brooder hatch rate
fecundity
Developmental stages in invertebrates
- larval stages
- metamorphosis
- direct development
e.g. of larval stages
- caterpillars
- tadpoles
Common larval forms
- trochophore
- veliger
- nauplius
- planula
Free-swimming planktonic marine larva with several bands of cilia
trochophore
e.g. of trochophore
- annelids
- molluscs
what is used in trochophore
cilia
- larva typical of certain mollusks such as marine snails and bivalves and a few freshwater bivalves.
- develops from the trochophore (q.v.) larva and has large, ciliated lobes (velum). The velum forms from the ciliary ring (prototroch), a characteristic of the trochophore stage
veliger
e.g. veliger
many molluscs
how does a veliger feed
filter feeding
- first planktonic larval form of most marine and of some freshwater crustaceans, from barnacles to anostracans to decapods
- free-swimming
Nauplius
e.g. Nauplius
crustaceans
- free-swimming or crawling larval type
- common in many species of the phylum Cnidaria
Planula
e.g. Planula
cnidarians
- transformation of morphology from juvenile to adult form
- Dramatic change in the form and often the habits of an animal during its development after birth or hatching
metamorphosis
Two types of metamorphosis
- holometabolous
- hemimetabolous
complete metamorphosis
holometabolous
incomplete metamorphosis
hemimetabolous
in entomology, sexually immature insect that is usually similar to the adult form
nymph
type of development in which a young is directly born as a small version of an adult and it develops into a mature individual without undergoing metamorphosis.
direct development
e.g. direct development
snail
ensure survival and genetic diversity
asexual and sexual reproduction
unique adaptations that offer reproductive flexibility
- hermaphroditism
- parthenogenesis
