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19 Cards in this Set
- Front
- Back
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Describe phylogenetic trees and their components |
Phylogeny=a graphical representation of the relationship between different groups, like species.-made from a lot of data gotten using modern analytical tools and phylogenetic inferences, e.g. similarities (physical, in DNA sequences, etc.).-a clade: a group of related entities in a phylogenetic tree.-MRCA: most recent common ancestor.--each clade has an MRCA.-phylogenies represent evolutionary history and current relationships.-phylogenies can also help us model carbon flux on a larger scale (because plants fall differently in phylogeny depending on ways of fixing carbon). |
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Describe the tree of life simply |
-three main domains: bacteria, archaea, eukaryota.-many drawing have been made to represent the tree of life.-all the present species today are the same age. |
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Give a brief overview of plant diversity |
-it's very easy to mess up a tree of life; need to be aware of what you're looking at.Plant diversity:-early land plants (e.g. bryophytes).-early vascular plants (e.g. selaginella).-gymnosperms (e.g. conifers).-flowering plants.-equisetum (horsetails).-ferns. |
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Describe the lifecycle of flowering plants |
Lifecycle:-has flowers, which have ovaries with ovules.-undergoes meiosis to give rise to female gametes and pollen (which is haploid).-fertilisation: get diploid zygote, which becomes an embryo, and eventually a seed.-seed and ovules are enclosed (not exposed).-double fertilisation takes place: •pollen comes in and has two nuclei (both same genotype).•ovule has multiple nuclei too.•one pollen nucleus fuses with one ovule nucleus to form the zygote, while the other pollen nucleus fuses with the rest of the ovule nuclei to form the endosperm.•the endosperm is a larger tissue functioning as a nutrition source for the growing seed. •the endosperm can be triploid or even higher.•the endosperm has more maternal genes than paternal, and this is because it'll be more likely to be able to extract resources from paternal plant.•endosperm can also signal if the gamete is good or bad.-some plants can be female or male sterile, meaning they're missing the female or male reproductive structures. |
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Describe the parts of the flowers in flowering plants |
-pedicel: the stalk the flower rests on.-sepal: leaves around flower; can be open or closed to enclose flower. Group of sepals: Callix-petals: display part. Group of petals: Corolla.-stamen: male part. Includes filament (stalk part) and anther (on top of stalk).-ovary: has ovules.-style: female stalk thing with stigma on the end. |
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Describe the classification of flowering plants |
-classification is now largely driven by statistical processes, e.g. looking at DNA sequences and arranging species in a hierarchial manner.-origin of classification: classification was based on sexual structures (by Linné). -reproductive structures play a role in compatibility, so they have to do with the distinguishing of species and classification.-Linné's classification was largely based on flower parts. |
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Distinguish between monocots and dicots |
Monocots:-1 cotyledon (embryonic leaf).-floral parts mostly in sets of 3.-leaves mostly parallel veined.-pollen uniaperturate.-have around 78-90 families.Dicots:-2 cotyledons.-floral parts mostly in sets of 4 and 5.-leaves mostly net veined.-pollen triaperturate.-have around 402 families.--there are 29 other families that aren't monocots or dicots, e.g. magnolias.-this is because these 29 families' most recent common ancestor came before the monocot-dicot separation was made |
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Describe nomenclature |
-based on Linné's system of binomial nomenclature.-plant species names include reference to the author, e.g. "genus" "species" L. (stands for Linné).-nomenclature follows very strict regulation according to the "International Code of Botanical Nomenclature", giving preference to the first name used, and defining rules for changing names with changing classification, e.g. Silene latifolia (has been named tons of times; confusion can happen).-is important when assessing biodiversity.-"The Plant List" includes >1 million plant names. |
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State the major events in the history of plants |
-origin of photosynthesis: ~2 bya. Lead to oxygen crisis.-origin origin of eukaryotes: ~0.9-1.5 bya.-origin of land plants: ~438 mya.-origin of vascular plants: ~408 mya.-origin of flowering plants: ~246-144 mya.-there has been a number of mass extinctions. They're used to define the end of time periods.-what we see today are the remnants of a bunch of evolution.-geological history and long-term climate change have had a profound impact on plant evolution, including the origin of flowering plants. |
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Describe herbariums and their use and importance |
Herbariums:-oldest collection present is from ancient Egypt.-many major plant collections exist, e.g. largest one in Paris.-plants are sorted by family.-each classification has a suffix, but sorting by family is most common.Now:-the information in herbariums is starting to be digitised: many plants now have barcodes.-anyone in the world can reach the databank, and more metadata can be added.-original use of herbariums was classification, but now it's more for saving biodiversity.-each plant gene has a story; when reconstructing a phylogeny you can reconstruct a gene's history.-plant evolution tends to be reticulate; found by using DNA sequencing.-but you need to be careful with the DNA sequencing type you use. |
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State four species-rich monocots families and four species-rich dicot families |
Monocots families:-orchidaceae: orchids. Is a highly diverse group and has a highly specialised floral structure and pollination mechanism; this is what has driven speciation.-poaceae: grasses.-cyperaceae.-bromeliaceae.Dicot families:-asteraceae.-leguminosae: has parasites on roots that fix nitrogen; are very important.-rubiaceae.-euphorbiaceae. |
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Describe the Fibonacci sequence and its significance in floral design |
floral parts come in 3, 4, or 5. Why?-because of the Fibonacci sequence (add current number with last number to get next number): 0, 1, 1, 2, 3, 5, 8, 13, 21, etc.-the Fibonacci sequence drives optimal stem growth and optimal packing.-the number of whirls, e.g. petals you count are numbers or multiples of numbers in the Fibonacci sequence |
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Briefly describe plate tectonics and global change across time and how it's significant for flowering plants |
-plate tectonics move due to continental drift.-8 major plates and several minor ones.-continents have changed over time: •Pangea was formed.•Pangea was then divided into two parts: Laurasia and Gondwanaland.•these later split into the continents we see now.-oceanic currents and oceans also change along with global climate over time.-global temperatures also fluctuate over geological time, we being in a cool phase now.-the Triassic period was where early angiosperms developed. It was very warm here.-in the late Cretaceous (94 mya), when the continents had broken up a bit, it gave room for huge differentiation in angiosperms, due to the change in climates. |
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Describe the fossil evidence from flowering plants found |
-not much fossil record found in the first place for angiosperms because their tissues are soft.-earliest angiosperm fossil found in China (a Jurassic fossil), of something that resembled magnolia.-earliest monocot fossil found in New Jersey, it being 90 million years old. Associated fossils found suggest that monocots evolved in tropical/subtropical climates. |
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Describe the molecular evidence found for the origin of flowering plants, mentioning MADS genes |
MADS genes: refer to a series of particular sets of genes that control decelopment.-MADS genes help provide insight to the origin of floral structures.-ABC model: categories of developmental/regulatory genes that control the development of whirls in flowers, e.g. B+C genes control stamens.-the B gene that codes for male structures share a common ancestry with angiosperms, so maybe they were mostly male?-some flowering plants are really weird though: Gnetales; are angiosperm-like conifers, e.g. Welwitchsia, are really weird, some believing they're extra-terrestrial. Form two leaves and have male and female cones |
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Describe the hypotheses on angiosperm origins |
A) Amborella is sister to all remaining angiosperms.B) Amborella and Nymphaeales are sister to all remaining angiosperms.C) Nymphaeales are sister to all remaining angiosperms.--hypothesis A has been found correct by using DNA sequencing.-shows Amborella is the most distant common ancestor, and Nymphaeales are the second most distant common ancestors.-examples of surviving species of "basal" angiosperms:•Amborella trichopoda•Nymphaea sp. (water lilies)•Austrobaileya scandens•Illicium sp. |
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Explain why the Cretaceous was a period of diversification for both plants and insects |
-has to do with flowering plants' relationship with insects; insects predate on flowering plants.-when Pangea split up, both flowering plants and insects diversified.-this is because insects change to be more effective predators, while flowering plants change to become more protected (is like an arms race).-this change in both groups shows congruence, and it accelerates speciation.Example: Chrysomelid beetles to Verbenaceae and Lamiaceae plants.-this diversification was also due to pollination (by insects, humans, etc.); there's a drive towards specialisation of flowers to attract pollinators, and pollinators become specialised too.-a flower only needs to be visited once for female success, while it can be successful many times for the male structures. |
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Explain how plant species would respond to climate change, giving an example |
-species would respond to climate change through range shifts.-the species' range of living areas basically moves/gets bigger.-the species end up investigating new environments and living there.-this ends up with distribution patterns changing.Example:-the desert shrub (Larrea tridentata) have left fossilised leaves that can be found and dated.-the ploidy of the plant is found by looking at guard cell sizes.-the fossils indicate range shift happening, while aligned with increasingly warmer summers. |
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Describe the future of biodiversity |
There are some major challenges:-population growth of humans (since 1950's, population has nearly tripled).-changes in land use (habitats get destroyed; nearly no more praerie habitats, and the agriculture and urbanisation in the UK limits biodiversity).-climate change (UK will change to have warm, dry summers).There have been many UN conventions.-now the IUCN red list keeps track of the status of species. It shows if biodiversity is getting better or worse.-a small percentage of flowering plants have been assessed, compared to mammal species, who have all been assessed. |
