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26 Cards in this Set
- Front
- Back
Transforming the World
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A. Origins/Diversifications of Seed Plants
B. Adaptations of Seed Plants |
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Adaptations of Seed Plants
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a) Dominant in bryophytes, but reduced in other seedless plants
(Ex. Pinecone – female gametophyte) b) Develop on parental sporophyte c) Parental sporophyte provides nutrients d) Parental sporophyte protects against environmental stresses (drought, disease, UV radiation, etc.) |
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Heterospory: differences in spores
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megasporangia and microsporangia
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megasporangia
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(in megasporophylls) produce megaspores that give rise to female gametophytes
Mega = Female |
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microsporangia
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(in microsporophyll’s) produce microspores that give rise to male gametophytes
Many microspores are produced |
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Ovules and egg production
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1.) Ovule
2.)) Layers of sporophyte tissue (integuments) envelop and protect the megasporangium |
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Ovule
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megasporangium, megaspore, and integuments; where eggs are produces
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Pollen and sperm production
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1)pollen
2)pollination |
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pollen
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pollen: mature microspores which carry the male gametophyte
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pollination
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transfer of pollen to ovules
• Carried by wind or attached to animals |
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Seed
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embryo, along with food supply, packaged within a protective coat derived from the integuments
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Advantage of Seeds
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a) Resistant to harsh environments
b) Able to disperse more widely c) Complexity with multicellularity |
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Gymnosperms
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- Plants whose seeds are not enclosed in ovaries (naked), not exposed on
modified leaves (needles), but located in cones • Examples: conifers (firs, pines, redwoods |
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Flower Features:
Coneds shaped cells |
on the surface of pedals allows pollinators to get a grip increasing the effiiency of pollination
Even flowers that feel smoooth offer traction Ex: Helps Bees hang on to flowers |
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Fruits
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1) can be either fleshy or dry
2)protect dormant seeds 3) assist in seed despersion Wind – dandelions Water – coconuts Animal exteriors – burrs Animal interiors – fruits |
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Cross pollination
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transfer of pollen from the anther of one plants to the stigma of aNOTHER PLANT (same species) for fertilization
(Facilitated by different maturation times or arrangement of reproductive organs) |
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Aftert the pollen lands on the stigma
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a pollen tube dsrows down the style, to the ovary and penetrates the in the interguments, fertilizing the egg
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Double fertilization
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occurs when sperm fertilizes an egg forming the embryo, and another sperm fuses with the central cell forming the endoderm (embryo nutrition)
*Unique to angiosperms |
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Evolution of Angiosperm
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1) Began to emerge 140 mya
2)Became a dominate group 65 mya 3) Common ancestor difficult to dertermin because of vast diversity 4)Relationships between pollinators and plants develops over time |
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Monocots
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Species with one colyldon
a) single cotyledon b)parallel leaf veins c)Scattered vascular tissue d) |
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Dicots
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species with two cotyledons
a) Double cotyledons b)Net like leaf veins c) Ringed vascular tissue d) Floral parts multiples = 4/5 e) Taproot system |
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Products from Seed plants
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six crops yield 80% of all calories comsumed by humans
*Wheat, rice, maize, cassava, potatoes and sweet potatoes *4.8 kg grain required for every 1.0 kg of grain-fed beef produced |
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Corn (maize)
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has undergone selective (artificial) breeding in ordewr to yield more food and taste better
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Medicine
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25% of all persciptions drugs contain one more active ingredients extracted or derived from plants
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Threats to Plant Diversity
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1. Increasing human population
2. Deforestation |
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Reduction of Plant Diversity
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1.Extinction of plants and animals directly dependant on those plants
2. Loss of potential new sources of food and medicine *Only 5,00 of 290,000 species have been explored by new sources |