Lab 6 Asexual And Sexual Reproduction Flashcards
Sexual reproduction
Involves the union of two gametes to form a zygote via fertilization
. It entails combing the chromosomes of parents to form offspring that have genomic contributions from both parents.
. Typically each parent produces gametes that are haploid ( 1n) and together produce offspring that are diploid.( 2n)
Individual fitness
Is a measure of the relative ability of an individual to transmit genes to future generations
Gametes
Sex cells - haploid 1N
Zygote
(zī’-goōt) The diploid cell produced by the union of haploid gametes during fertilization; a fertilized egg.
Fertilization
The union of haploid gametes to produce a diploid zygote. It entails combing the chromosomes of parents to form offspring that have genomic contributions from both parents.
Haploid
1N - a cell contains only one set of chromosome
1N
Having one set of chromosome- haploid
2N
Having 2 sets of chromosomes
What is the process that produces gametes
Meiosis
Meiosis
A 2N cells divide to produce 1N daughter cells within gonads or other reproductive tissues.
Gonads
(goō’-nadz) The male and female sex organs; the gamete-producing organs in most animals.
Why are both the gametes and and offspring produce genetically variable
Because chromosomes undergo independent assortment during meiosis
Mitosis
A type of cell division where a parent cell( typically diploid or 2N ) produce daughter cells that are identical ( also 2n).
. This type f cell division occurs in all tissues of human body except gonadal tissue. ( ovary and testes)
. (mī-toō’-sis) A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by allocating replicated chromosomes equally to each of the daughter nuclei.
Asexual reproduction
Involves the cloning of individuals.
. Offspring are produced via mitosis or similar mechanism of reproduction.
. Cloning may involve the production of duplicate animals or plants by budding or vegetative propagation.
Budding
Asexual reproduction in which outgrowths from the parent form and pinch off to live independently or else remain attached to eventually form extensive colonies.
Vegetative propagation/ reproduction
Cloning of plants by asexual means.
The cons of sexual reproduction
. Only 50% of genes gets passed on
. Spend energy finding a suitable mate
. Dangerous: competing for a mate
Pros of sexual reproduction
Genetic diversity
. When environments change there will be at least some offspring that will adapt to the new conditions.
Pros of asexual reproduction
. 100 % of offspring is passed on
. Short mechanism to generate large numbers of offspring that are adopted to existing environmental conditions.
. Less energy used in finding a mate.
. Less costly in finding a mate, competing for a mate, or producing gametes
PROTOZOANS reproduce by
Primarily by Asexual reproduction ( although sexual reproduction happens at times)
Protistans produce by
A common type of asexual reproduction called binary fission
Binary fission
A method of asexual reproduction by “division in half.” In prokaryotes, binary fission does not involve mitosis, but in single-celled eukaryotes that undergo binary fission, mitosis is part of the process.
. A type of asexual reproduction in which a prokaryotic cell divides into identical daughter cells
Protista
An informal term applied to any eukaryote that is not a plant, animal, or fungus. Most protists are unicellular, though some are colonial or multicellular.
The result of binary fission in PROTISTS
Since they are unicellular it results in both cellular reproduction and population growth
Protozoan
Unicellular protist that is heterotrophic and usually motile.
Eg of a heterotrophic protist - a protozoan
Paramecium caudatum
Most PROTOZOANS reproduce by
Asexual reproduction
Types of asexual reproduction
Binary fission
Budding
Mitosis
Budding
A similar process to binary fission but involves the formation of a progeny(a offspring) cell or organism that is much smaller than the adult cell or organism.
Egs of organism that reproduce by budding
Fungi : yeasts
Invertebrates : cnidarians ( corals, jelly fishes, hydra)
Fungi reproduce asexually by means of
A CONIDIA
CONIDIA
Are asexually produced non motile spores that are borne externally to the cells that produce them ( opposite to sporangiophores that are produced incident specialized cells / chambers called sporangia).
They are multinucleate that are cut off from the ends of specialized Salk like hyphae termed conidiophores
Eg of organisms that produce CONIDIA
Ascomycetes ( sac fungi)
Conidiophores
Are specialized hyphae stalks on which the CONIDIA ( spores) are borne
SPORES
Cells ( usually haploid) that are capable of germinating into an adult plant without fusing with another cell)
How are CONIDIA dispersed
By wind and may germinate( grow) to form new hyphae ( conidiophores )
Example of a ascomycetes that produce CONIDIA
Aspergillus
How do vascular plants reproduce asexuxually
With underground stems known as RHIZOMES
Rhizomes
Underground stems found in vascular plants
Egs. of vascular plants that reproduce asexually
. Grasses
. Strawberries
. Raspberries
Parthenogenesis
Involves development of eggs without fertilization
Eg. Of inveterate or vertebrate that reproduce asexually ( via parthenogenesis )
.Cnemidophorus lizard ( whiptail lizard) that consist entirely of female lizards. Female produce eggs that begin developing into a female offspring
. Daphnia ( these switch to sexual reproduction when the habitat gets overpopulated)
. Aphids(
Alternation of generations
Cycles involving diploid ( 2n) and haploid( n) generations that alternate
Explain the life cycle of fern ( alt of gen)
- The leafy part of the fern is the diploid stage …. SPOROPHYTES ( “spore-plant”). 2N
- When mature the sporophyte produces reproductive chambers termed ….SPORANGIA/ ( a cluster of sporangium is called a SORUS) ( 2N)
- Special tissues within each sporangium undergoes meiosis to produce haploid SPORES (N)
- Spores are released from the sporangium and eventually germinate( grow ) to form young GAMETOPHYTES.
- When mature the gametophyte produces reproductive chambers in which gametes are produced by mitosis.
5a. Reproductive chambers that produce eggs are called….ARCHEGONIA
5b. Reproductive chambers that produce sperms are called …. ANTHERIDIA. - Gametes that are released from the chambers join to form a diploid ZYGOTE (2n)
- The zygote matures into a sporophyte
Gametophyte
(guh-mē’-toō-fīt) In organisms (plants and some algae) that have alternation of generations, the multicellular haploid form that produces haploid gametes by mitosis. The haploid gametes unite and develop into sporophytes.
SPOROPHYTE
(spoō-ruh-fīt’) In organisms (plants and some algae) that have alternation of generations, the multicellular diploid form that results from the union of gametes. The sporophyte produces haploid spores by meiosis that develop into gametophytes.
SPORANGIA
The reproductive chambers produced by sporophytes. Tissues in the chambers undergoes meiosis and produces haploid spores
ARCHEGONIA
Reproductive chambers of gametophyte that produce egg cells by mitosis.
Antheridia
Reproductive chambers of gametophytes ( haploid )that produce sperm cells ( haploid)by mitosis.
ZYGOTE
(zī’-goōt) The diploid cell produced by the union of haploid gametes during fertilization; a fertilized egg.
An bvious difference between plant and animal life cycles
In animals meiosis results in the formation of gametes that unite to form a zygote.
In plants meiosis results in the production of haploid spores that grow into a different life form ( the gametophyte ) that produces gametes when mature.
Life cycle of a moss in terms of alternation of generation
- The leafy portion of the moss is the GAMETOPHYTE ( haploid) 1N
- Individual moss plants are either male or female
- On top of the gametophyte, either ANTHERIDIA or ARCHEGONIA are produced depending on the sex of the plant
- Archegonia produce egg cells by mitosis.
- Antheridia produce sperm by mitosis
- After a rain, sperm released from the antheridia swim through drops of water over to an adjacent female plant and make their way down the archegonium
- fertilization occurs at the bottom of the archegonium to produce a ZYGOTE ( diploid 2n)
- The zygote remains in place and develops into a mature SPOROPHYTE
- Yellow or greenish stalk- like structures that are attached to the tops of the gametophytes are the mature SPOROPHYTE ( this always a female plant because it holds the zygote and zygote matures in place)
- At the top of each sporophyte is an enlarged chamber a SPORANGIUM called …. A CAPSULE.
- Within the CAPSULE MEIOSIS occurs to produce thousand of haploid spores.
- The haploid spores are dispersed then soon germinate into a young gametophyte that will mature into a moss plant.
FRONDS
The leafy part of the fern that is the sporophyte
The cluster of SPORANGIA beneath the FRONDS are called
SORI
Where are spores of ferns usually dispersed
By air to micro habitats along stream banks or on the forest floor
Where on the fern gametophyte is the antheridia and the archegonia produced
On the surface
What type of plants have a life cycle do I aged by the gametophyte stage
BRYOPHYTES such as moss and algae
In gymnosperms and angiosperms the gametophyte stage is greatly reduced.
What is the dominant stage in gymnosperms and angiosperms
The sporophyte stage
Sex involving 2 kinds of gametes
OOGAMY
Sex involving one kind of gamete
ISOGAMY
Flowering plants produce two kinds of sporangia
- Mega spores
2. Microspores
MEGASPORES
Germinate and grow into egg yielding megagametophytes
Megagametophytes
Gametophytes in flowering plants that produce eggs
MICROSPORES
Germinate and grow into MICROGAMETOPHYTES THAT PRODUCE SPERMS
MICROGAMETOPHYTES
Gametophyte of flowering plants that produce sperms
Plants that make 2 kinds of spores are called
Heterosporous
Plants that make only one kind of spore is
HOMOSPOROUS
In angiosperms the dominating life cycle stage is
The SPOROPHYTE stage
The mega gametophyte is is reduced in angiosperms to a 7 - called structure called
The embryo sac
The EMBRYO SAC
The 7- called mega gametophyte that is found in the ovary of the flowers of the parent sporophyte plant.
.Within the embryo sac, the mega gametophyte, an egg is produced and waits there for the arrival of another gamet
FLOWERS consist of a series of highly modified leaves that form which parts
Sepals
Petals
Stamens
Pistil
SEPALS
The outermost whorls of modified leaves that serve to protect the underlying reproductive structures or attract pollinators
PETALS
The next innermost whorl of modified leaves and serve primarily to attract pollinators
STAMENS
Are attached to the inside of the petals and bear long chambers called ANTHERS
ANTHERS
Long chambers born from the stamen. They are microsporangia
What occurs inside the ANTHERS
Special cells undergo meiosis to produce MICROSPORES
Plants such as BRYOPHYTES and algae life cycle are dominated by what stage
The gametophyte stage
The stamen ( the male part of the flower) is made up of 2 parts
The filament and the anther
The 4 parts of the Female part of the flower the PISTIL ( the vase shaped structure at the center of the flower and functions as the female reproductive structure)
Stigma
Style
Ovary
Ovule
the MICROSPORES. Produced in the ANTHERS germinate within the anthers and develop into whaT
Male gametophytes ( pollen grains).
The life cycle of an angiosperm
- Cells within ANTHERS ( MICROSPORANGIA)(1N) undergo MEIOSIS and produce MICROSPORES.
- The MICROSPORES (1n) develop into MICROGAMETOPHYTES (( POLLEN GRAINS).
- In the female structure of the plant the MEGASPORANGIA ( the OVARY). It contains the FEMALE GAMETOPHYTE ( EMBRYO SAC) found inside an ovule. It contains an egg nucleus that serves as a gamete.
- When a pollen grain is placed on the stigma on a receptive flower the pollen grain grows into a filamentous thread contains 2 SPERM NUCLEI and 1 TUBE NUCLEUS that controls the growth of the pollen tube.
- The pollen tube grows through the style to the ovary where it merges with the embryo sac of the ovule , dumping the sperm nuclei near the egg nucleus
- Fertilization follows ( involves one sperm nucleus and egg nucleus uniting to form a ZYGOTE.
- The second sperm nuclei unites with 2 polar nuclei in the egg sac to form a Triploid tissue- THE ENDOSPERM
- After double fertilization, usually the flower parts other than the ovary dry up and fall away
- The ovary undergoes a tremendous increase in size, rate of synthetic activity and change in overall appearance.
. When this process is completed the ovary has become a fruit, and the ovule a seed
- The fruit falls to the ground and eventually germinates into a seedling
- The seedling develops into a plant with flowers
STIGMA
The sticky upper platform that captures pollen
STYLE
The long neck of the pistil
THE OVARY
The large base which contains the OVULE
The female gametophyte is
The EMBRYO SAC
The EMBRYO SAC
The female gametophyte.
. it found within the ovule inside the ovary
. It contains an egg nucleus that serves as a gamete
Sporophyte stage in angiosperms
Embryo, green plant, stem leaves, flowers or cone
