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103 Cards in this Set
- Front
- Back
When did prokaryotes show up in the fossil record |
3.5 billion years ago |
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steps to achieve the origin of life |
1. Abiotic synthesis of small organic molecules 2. Turn them into macromolecules 3. Package them into protocells 4. Origin of self replicating molecules |
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Protocells |
Membrane bound droplets that maintain an internal chemistry different from their surroundings |
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What protocells required to become life |
Self-replication and metabolism |
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Vesicles |
Fluid filled environments with membrane structures |
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Shapes of prokaryotes |
Sphere (cocci), rods (bacilli), spirals |
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Gram-positive |
Simple cell walls |
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Gram-negative |
More complex cell walls |
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Phototroph |
Obtains energy from light |
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Autotroph |
Uses CO2 as energy source |
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Chemotrophs |
Energy from chemicals |
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Heterotrophs |
Uses organic carbon as energy source |
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Factors of prokaryotic variation |
Rapid reproduction Mutation Genetic recombination (horizontal gene transfer) |
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Cytoskeleton |
Allows eukaryotic cells to change shape |
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When did eukaryotic cells shown up |
1.8 billion years ago |
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When did multicellular eukaryotes show up? |
1.2 billion years ago |
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Endosymbiosis |
proposes that mitochondria and plastids were formerly small prokaryotes that began living within larger prokaryotes |
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Multicellular Colonies |
Worked as a unit and formed filaments, balls and cell sheets |
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Biodiversity |
measured by the number of species in an area |
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Counters to Species Concept |
Asexual Organisms, domestic dogs, cryptic species (Contains individuals identical to each other, but cannot interbreed) |
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Two concepts Biodiversity implies |
1. Can identify a species 2. Can identify a habitat (site occupancy) |
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Counters to Site Occupancy |
Are the species there or just undetected |
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Problems with measuring biodiversity |
1. It's difficult to measure abundance of species and identity of species accurately 2. Difficult to compare species in different sites 3. Debate about metrics 4. Is biodiversity affected by ecosystem services 5. Linguistic uncertainty |
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Benefits derived from Ecosystems |
Food security, clean air, clean water, pharmaceuticals, aesthetics/ ecotourism |
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Species Richness |
The number of species found in a defined area |
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alpha biodiversity |
within habitat diversity (observed) |
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gamma biodiversity |
total diversity (observed) |
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Beta diversity |
between habitat diversity (estimated) |
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equation for biodiversity |
beta = gama/ (average of alpha) |
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species eveness |
shows whether species are evenly distributed |
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maximum species richness |
achieved by taking more and more samples |
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When small plants, fungi and animals emerged on land |
500 mya |
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when plants emerged on land |
470 mya |
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when cynobacteria emerged |
1.2 bya |
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first forest emerges |
385 mya |
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Charophytes |
Green Algae. The closest living relative to plans |
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Sporopollenin |
A polymer like substance found in charophytes that reduced desiccation in zygotes. Allowed plants to move to land |
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Why plants moved to land |
1. open niches 2. better light 3. easier CO2 |
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embryophytes |
plants with embryos |
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Key traits in land plants that are absent in chlorphytes |
1. alternation of generations 2. apical meristems 3. multicellular, dependent embryos 4. walled spores produced in sporangia |
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Alterations of generation |
All life cycles of plants alternate between two distinct multicellular organisms: gametophytes (haploid/ mitosis) and sporophytes (diploid/ meiosis) |
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Apical Meristems |
localized region of cell division at the tips of roots and shoots |
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Derived Traits in Plants |
1. Cuticals: a waxy covering in the epidermis that prevents water loss/ microbial attack 2. Stomata: specialized pores that allows the exchange of CO2 and O2 between outside air and plant |
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Diversification of plants on land occurred... |
400 mya |
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Mycorrhizae |
symbiotic associations between fungi and plants that helped plants obtain nutrients |
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yeast |
single celled fungi |
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mycelia |
networks of branched hypae (filaments that allow nutrient absorption) |
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Fungi Reproduction |
They produce vast number of spores that can produce asexually or sexually |
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Closest relative to fungi |
nucleariids |
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Fungi emerge |
460 mya |
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when do fungi/ plant associations occur |
405 mya |
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vascular plants emerge... |
420 mya |
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byrophytes |
nonvascular plants anchored to the ground by rhizoids: liverworts, mosses and hornworts |
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xylem |
conducts mostly water through tubed-shaped cells called tracheids that are made of ligin |
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pholem |
cells arranged in tubes that distribute sugars, amino acids and other organic products |
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advantage of vascular plants |
increased height |
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seed plants emerge... |
360 mya |
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seed |
embryo and food supply. Increased survival |
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Gymnosperms |
Have naked seeds that are not enclosed in chambers |
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Angiosperms |
Have seeds that develop in chambers called ovaries. Also have flowers/ fruit and are the most diverse plant group |
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gymnosperms appear... |
305 mya |
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conifers |
gymnosperms that bear cones |
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angiosperms appeared... |
140 mya |
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lichen |
pioneers, they form a symbiotic relationship with their environment |
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Photosynthesis removes CO2 from air which leads to... |
Global cooling |
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Choanoflagellates |
a single celled eukaryote that is similar to the cell that animals evolved from |
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origin of animals occures |
700 mya |
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Edicararen Biota |
Earliest animal fossils. Around 560 mya |
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sponges |
filter feeders that lack true tissues. Basal taxa of animals |
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Chanocytes |
type of cells in a sponge that generate a water current through the sponge |
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Cnidarians |
Show up 680 mya. Includes animals like jellies. They have a gastrovascular cavity and predator/ prey interactions |
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Cambrian Explosion |
535 mya. Large radiation of life |
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Hypotheses of the occurrence of the Cambrian Explosion |
1. New predator-prey interactions 2. Rise in O2 3. Evolution of the Hox gene |
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Three Aspects of Body Plans |
1. Symmetry 2. Tissues 3. Body Cavities |
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Arthropods |
Segmented bodies, hard exoskeleton and jointed appendages. Makes up 2/3 of animal species |
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Myllokummigia fengiaoa |
Ist known chordate. Lived 530 mya. It lacked armor and appendages |
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Vertebrates |
Have a back bone made out of vertebrae |
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Chordates |
1. notochord 2. Dorsal/ hollow never cord 3. Pharyngeal slits 4. muscular, post-anal tail |
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Lancelets |
basal taxa of chordates |
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what animal group was the first to colonize land and when |
arthropods and 450 mya |
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when do vertebrates colonize land |
365 mya |
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cuticle (animals) |
an exoskeleton made of layers of protein and chitin. (helps prevent drying out) |
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Tiktaalik |
A fishapod... it had fins, gills, lungs and scales. It had ribs, shoulder bones and neck. It is marked as a major key in tetrapod evolution. (365 mya) |
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When did Earth form |
4.6 bya |
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Ribozymes |
RNA molecules that catalyze many different reactions |
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Diameter of a prokaryote |
0.5-5 micrometers |
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Peptidoglycan |
networks of sugars crossed linked by polypeptides. These are part of prokaryotic cell surfaces |
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Archaeal cell walls |
made of polysaccharides and proteins |
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Fimbrae |
allow bacteria to stick together |
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Pili |
like fimbrae, but allow DNA to exchange |
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Genetic Recombination |
combines DNA from two sources and is achieved through transformation, transduction and conjugation |
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Shared characteristics of plants and charophytes |
rings of cellulose synthesizing complexes and structure of flagellated sperm |
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large plant structures show up... |
425 mya |
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fungal cell walls are made of... |
chitin |
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similarities between seed plants |
reduced gametophytes, ovules and pollen |
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endophytes |
fungi that live inside leaves or other plants |
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ameobocytes |
cells in sponges that help with digestion and structure |
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bilaterans arose around... |
660 mya |
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tissues |
collections of specialized cells isolated from other tissues by membrane layers that act as a functional unit |
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body cavity |
may cushion suspended organs, act as a hydrostatic skeleton, and enable internal organs to move independently |
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eumetazoas |
animals with true tissues |
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Points that are reflected in animal phylogeny |
1. all animals share a common ancestor 2. Sponges are basal animals 3. Eumetozoas are a clade of animals with true tissues 4. most animals are bilaterans 5. most animals are invertebrates |
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gnathostomes |
jawed vertebrates |