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Reproduction
By Aimee Chavez
Sexual Vs. Asexual
Sexual reproduction: ( Meiosis) 2 parents and one or many offspring with genetic diversity
Examples: sperm + egg = zygote
seed plants
Asexual reproduction (mitosis) 1 parent and one or many offspring which are an exact copy of the parent.
Sexual vs. asexual
Mitosis & The Cell Cycle
Reproduction of regular body cells such as skin cells. An exact copy is made.
Meiosis and Sex Cells
Meiosis: a process that produces 4 sex cells (haploid) which have 23 chromosomes. Sperm or egg.
Often there are mistakes during meiosis and a cell can have too few or too many chromosomes. I.e. Downs syndrome
Sprouting
Some vegetables such as sweet potatoes which grow sprouts can reproduce asexually.
Strawberries form runners & fragmentation
Budding
Some organisms such as hydra and sponges can reproduce through a process called budding.
Regeneration
Sea stars, Planarians, Lizards can regrow a body part called regeneration.
Binary Fission
Bacteria and amoeba reproduce via binary fission.
Bacteria:
need food, temperature, and suitable living conditions
Asexual: Binary fission. One cell divides to form two identical cells
Sexual: some reproduce by conjugation where 2 parents who combine genetic information. No babies!
Fungi:
spores are surrounded by a covering and are carried thru air and water. The spores are produced in fruiting bodies which are reproductive hyphae.
Asexual: adequate moisture and food, reproduce by fruiting bodies that become spores
Unicellular yeast uses budding where a small yeast cell grows from body and breaks off as a new organism.
Sexual: unfavorable hyphae of two grow together and genetic material is exchanged , new spore producing structure grows from the formed hyphae
Protists:
asexual or sexual
Amoeba: asexual replicates nucleus and fission occurs
Fungus like produce spores
Sexual: stress like from environment offspring have better survival a gamete becomes a zygote
Plants:
two stages or generations
Sporophyte: produces spores and gametophyte: produces sex cells sperm and egg
Spores gametophyte to sperm and egg zygote to sporophyte
Gymnosperm: cones and naked seeds needle like scale like deep roots
Produces male and female cones
Scale on female has 2 ovules male produces pollen grains that mature to sperm
Egg cell develops inside ovules
Wind scatters pollen which becomes trapped on sticky ovules
Pollen produces a tube which grows into ovule sperm moves through and joins with the egg
The ovule becomes a seed and egg becomes an embryo
Wind disperses the seeds which become a seedling and a tree
Angiosperms: flowering plants Angiosperm produces flowers
Inside ovary an egg cell is produced in each ovule cells in the anther produce pollen
Pollen gets trapped in the stigma
Pollen grains produced pollen tubes that grows into ovule a sperm cell moves through the pollen tube an joins with the egg cell
Ovule becomes a seed and fertilized egg becomes and embryo
Ovary becomes a fruit with seeds
Seeds become a new plant
Sponges
Sexual: sperm and egg make larva immature and looks different than adult
Asexual: Budding
Cnidarians: polyps: budding sexual
Worms:
sexual and asexual some are male and female
Asexual: breaking into pieces, except earthworms which can only grow back tail : regeneration
Insects:
Complete metamorphosis Egg female in moist place
Larva egg hatch to larva
Pupa sings legs antenna form protective case
Crawls out unfurls wings exoskeleton hardens
Gradual metamorphosis
Egg to soil
Nymph looks like mini adult no wings
Larger nymph molts
Adult wings
Amphibians
Frogs and toads have external fertilization salamander is internal
Eggs have a clear jelly moist and protective
Egg to legless tadpole to hind legs to frog to adult
Reptiles: eggs fertilized internally shell
Birds: internal fertilization and lay eggs have harder shells
Mammals: internal fertilization
Young develop in mom feed with milk
