Ch11: Reproduction Flashcards
Difference between asexual and sexual reproduction?
ASEXUAL:
- only 1 parent
- offspring are genetically identical (placing them at risk of extinction in environmentally variable environments)
- suitable to CONSTANT environments
- Quicker population growth (less time/energy spent trying to find a mate)
- can have booms in population
SEXUAL:
- 2 parents
- offsprings genetically variable which allows for evolution + adaptation and selection
- Slower to reproduce; takes time to find a mate, and only HALF of population can reproduce
What are the 5 types of asexual reproduction?
1) Fission (binary or multiple)
2) Fragmentation (echinoderms)
3) Vegetative Propagation
4) Parthenogenesis
5) Budding (fungi - single cell)
What are the 2 kinds of sex assignments in sexual reproduction?
1) Dioecious: organism is either male or female reproductively
2) Monoecious: organism can reproduce (be a male OR a female) simultaneously or change sex at different points in life
What are the 2 kinds of embryo development?
1) Oviparous: embryo develops and is laid externally (as an EGG)
2) Viviparous: develops internally (in parent)
Where can embryo fertilisation happen?
Inside the organism OR outside (through water)
Define fission, binary fission, and multiple fisson
Fission: separation of a parent organism into genetically identical daughter offspring (equal in size)
Binary Fission: a parent enlarges as the nucleus DOUBLES, and splits into genetically identical organisms (EQUAL in size)
Multiple Fission: a multinucleated organism forms cytoplasm around these nuclei and then split into equally genetically identical daughter cells (occurs under specific conditions)
Define Budding:
form of asexual reproduction: an outgrowth on the parent organism that eventually splits off (NOT EQUAL in size)
- can occur in specified regions
Define fragmentation
A part of the present organism is BROKEN off
This is then replenished/grown back and the fragment is able to develop into a mature, functional individual that is IDENTICAL in shape, and genetics
Can occur intentionally or unintentionally
Define parthenogenesis
The development of a gamete to an identical individual
The gamete is either unfertilised (haploid) or unfertilised (diploid) (can determine sex)
Seen in sexually reproducing organisms: benefit from both reproductions under difference conditions
Define vegetative propagation
Shoots + runners + suckers grow away from the parent plant, to find an environment appropriate (with resources)
Once it finds that environment: the stem fragments leave a portion to grow into a daughter plant: reduces competition + enables population persistence
Define apomixis, what does it allow for?
The production of seeds without having pollination or fertilisation.
It allows for some plants (HYBRIDS) to overcome sterility
What are artificial ways of making new plants
Grafting: attaching the top (scion) and bottom (rootstock of 2 plants together) to mix and produce desired traits
Cutting
Layering
Micropropagation
Define fertilisation:
when 2 daughter cells fuse to form a diploid zygote
What does alternation of generations mean?
organisms change between haploid and diploid stages
Describe Plant reproduction
See Doc, 11a:
- Spores of plants undergo MITOSIS to produce multicellular haploids (GAMETOPHYTES)
- 2 Gametophytes pair = fertilise each other to form a DIPLOID ZYGOTE
- This zygote undergoes MITOSIS to form a multicellular diploid (SPOROPHYTE)
- The sporophyte undergoes MEIOSIS to form individual HAPLOIDS that spread out as SPORES
Describe the fertilisation of fungi: and their sexes
See Doc, 11b:
Mate usually asexually of by clade: most are NOT male or female (any 2 sexually reproducing fungi can mate)
MATE:
- Fuse together to form 1 PLASMOGAMETE = cytoplasm of 2 haploid individuals fuse to form a DIKARYOTIC INDIVIDUAL (a cell that has two nuclei, one from each parent cell, and shares a single cytoplasm)
Then their nuclei fuse to form a DIPLOID;
KARYOGAMY = meiosis occurs + haploid spores are released to form mycelium + begin cycle again
What are the benefits of monoecious reproduction?
- all members of a species can reproduce
- Genetic diversity can occur due to mixing of haploids
Define angiosperms
Flowering parts of plants
What are the male and female parts of a flowering plant?
See Doc, 11c:
Male: Pollen, Stamen, Filament
Female: Ovaries, Stigma, Style, Ovules (eggs)
Difference between simultaneous Hermaphrodites and sequential hermaphrodites
Simultaneous: Produce both sperm + eggs at same time, male or female throughout their lives
Sequential: dictated by condition, social structure or age (if mates low = become missing sex)
Benefits of dioecious reproduction
Guaranteed genetic variation + reduces risk of self-fertilisation
What are the 2 different kinds of gamete investment (related to size) called?
1) Isogamy: gametes are equally involved in by both parents and the gametes = same size
2) Unequal gamete parental investment, meaning 1 produces a larger gamete, whilst 1 = less and therefore small gamete
usually males make = smaller gametes but more, whereas females = fewer but larger
What are the parts of a flower
See Doc, 11d:
Sepals: encase + protect the plant (bottom of the flower)
Petals: protect the plant, bright to attract pollinators
Stamens: fertile flower organ, release spores that become sperm + eggs
- made of filament + anther (secrete pollen grains that develop into sperm)
Carpels: Consist of ovary, style + stigma:
- ovules = egg sacs (embryos)
- style = connects ovary + stigma
- Stigma = sticky + traps mobile sperm to reach stationary egg (ovules)
What happens to fertilised ovules?
Pollintaor (sperm source) to ovules
Flowering plants: pollen is transferred from another (stamen) to stigma (by pollinators)
Then a pollen tube is formed (connect stigma to ovule) = sperm is released into ovule
Fertilisation occurs = flower develops into fruit + ovule becomes a seed
What happens to unpollinated flowers?
Unpollinated flowers fail to become fruit and die
