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24 Cards in this Set
- Front
- Back
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Reproduction plants vs animals
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plants routinely have multiple modes of reproduction, animals generally stick to one
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natural selection
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selection among variation that exists in the natural populations for the organisms that are the best fit with the environment (many more organisms born than can survive)
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advantages / disadvantages of sexual reproduction
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+ novel combinations of genes for natural selection to work on
-> greater potential for adaptation when conditions change - energy & resources devoted to mating - dependent upon finding a mate |
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advantages / disadvantages of asexual reproduction
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+ no need to find a mate, don't devote resources, may be able to reproduce earlier in life
+ offspring likely to do as well as parent - less genetic diversity |
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modes of asexual reproduction
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stolons - above ground stems
rhizomes - below ground stems reiteration - new from break or damaged stem layering - corms & tubers - fleshy stem sections bulbs - fleshy stems, thickened leaf bases, new plant from lateral stems suckers - sprouts from roots leaf fragments - leaf margins apomixis - produce seeds that are clones of the parent - no recombination |
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apomixis
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reproduction via seeds that are clones of the parent
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in plants, what are the mobile gametes?
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mosses and ferns - swimming sperm
seed plants - pollen grains that produce male gametophyte |
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Totipotent:
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cells retain all of the genetic information (encoded in DNA) necessary to develop into a complete plant
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Xylem
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Carries water and inorganic solutes (N, P, K) from the roots to the leaves
Usually xylem tubes are located inside the plant |
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Phloem
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Carries organic solutes (e.g. sucrose) from the leaves throughout the plant
Usually phloem is located outside of xylem |
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self-fertilization
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less raw material for natural selection to act upon
approx 50% of species are self-incompatable strategy of last resort |
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reproductive assurance
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when a plant will allow self-fertilization if cross fertilization has not occurred.
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strategies to avoid self-fertilization
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spacial separation of gametes
temporal separation of gametes incompatable |
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protogynous, protoandrous
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temporal separation of gametes in plants
protogynous - female first protoandrous - male first |
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monecious, diecious
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monecious - plants have both make and female parts
diecious - plants have either one or other sex, not both |
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pre- and post-zygotic reproductive isolation
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pre-zygotic reproductive isolation - prevent fertilization
post-zygotic reproductive isolation = embryo fails to develop from incompatible pollen |
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ramet
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individual member of clonal group - eg single aspen tree
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genet
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genetically distinct individual - eg clonal group of aspen trees
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life history strategies
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- allocation of resources between growth, defense, reproduction
- timing of reproduction - seed requirements - small vs large seeds |
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tolerance - fecundity tradeoff
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inverse relationship
high stress environment -> big seeds to provide nutrients more reproduction - shorter life spans indicator of reproductive effort in plants => seed size |
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monocarpy
iteropary semelpary |
monocarpy, semelpary = reproduce once in a lifetime
iteropary = multiple reproductive bouts |
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r vs K
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life history strategies
r = intrinsic rate of reproduction - fast growth, many offspring, low investment in each K = carrying capacity, slow growth, few offspring, high investment in each offspring |
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Competitive vs Stress tolerant vs Ruderal
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Grime 1977: C & S are variants of K strategy
C - allocate resources to growth S - resources to stress tolerance, maintenance, defense R - resources allocated to reproduction - early successional |
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life form diversity -
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epiphytes, hemiepiphytes, vines / liannas, epiphylls, mosses & ferns, herbs, shrub, under canopy, canopy, emergents
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