Bio 201 Exam 2 Review PDF

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BIO 201 Midterm Exam 2 Review...

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PLANT DIVERSITY Extinction- death of a taxon or lineage. It is a natural process that is always occurring but at a very low level, called “background extinction.” “Mass extinctions” occur at significantly higher rates; 5 have occured in history; various causes contribute to each mass extinction. Defined by extinction rate Natural experiment- biologists compare a system before and after a naturally occurring event. Strength- realistic; weakness- no control Feature of lineages that may help survival in mass extinction: geographically widespread taxa The environment drastically changes during mass extinctions, so certain adaptations that were once useful (during background extinction) may not help during mass extinction Origin of land plants from algae Almost no soil is used up by a plant as it grows. The vast majority of a plants mass comes from the air (CO2 in the air) Plants (and most organisms) are made of carbon. During photosynthesis, CO2 is broken down to make sugars, which can be used as food to build the plant In trees, carbon is much more tightly packed than in the air. When wood is burned, most of the mass goes into the air as CO2 (NOT photons or heat energy) Land plants: mosses, ferns, gymnosperms, angiosperms. Closest living relatives: charophytes- algae Stoneworts (coleochaetophytes and charophytes; a type of algae)- closest relatives of land plants. They are the outgroup, not the MRCA. They evolved from the same common ancestor at some point, but land plants did not evolve from the stoneworts How land plants changed Earth’s atmosphere: increase in O2 production, decrease in CO2 Land plants consequences: decrease in global temperature, the evolution of giant insects 4 characters and their character states associated with evolution of land plants: 1) Cuticle (absent/ present), 2) Stomata (absent/ present), 3) Vascular tissue (absent/ present), 4) Sexual mode (gametophyte dominant/ sporophyte dominant) 1) Cuticle- all land plants have a cuticle (like a skin; prevents water loss and helps with UV protection, though it prevents gas exchange… this is why all land plants also have a stoma) 2) Stomata- all land plants have stomata (structures within cuticle of plants that open and close to allow for gas exchange- CO2 in, O2 out) 3) Vascular tissue- present in ferns, gymnosperms, and angiosperms but not in mosses because they are small (2 types of vascular tissue- xylem for water transport and phloem for sugar aka food transport). The vascular tissue is for transport, therefore it is present in larger plants (all but mosses which are very small) Coal is fossilized plants. These carbon molecules have been stored for much longer than wood. Coal is more compressed, so there is more matter and energy in coal than wood, and more matter (carbon) is released when it is burned than wood

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Examples of adding carbon into the atmosphere: burning coal, burning wood, human breathing, charging phone, driving a car. 4) Sexual mode: All plants have gametophyte (n) (make gametes) and sporophyte (2n) (make spores). (Parts of the life cycle). Ancestral plants (mosses) are gametophyte dominant (gamete forming structure is much bigger and lasts longer), whereas in more modern plants (ferns, gymnosperms, and angiosperms) the sporophyte is larger and lasts longer). In other words, mosses which are the more ancestral land plant, have much larger gametophyte than sporophyte, whereas ferns, gymnosperms, and angiosperms evolved to have larger sporophyte than gametophyte In moss: meiosis produces spores, and mitosis produces body cells or gametes Gametophyte- tissue that makes gametes Gametes- make sporophyte Sporophyte- tissue that makes spores Spores- make gametophyte Conifers- a type of gymnosperm. They produce cones which contain seeds. They produce wind-blown pollen (NOT swimming sperm). They do not require water for fertilization. The male cone produces the pollen and fertilizes the egg by releasing it onto the female cone male= micro; female= mega. The microspore produces the microgametophyte (aka pollen) which produces the sperm. The megaspore produces a megagametophyte (aka egg sac) which produces the egg. Conifers & angiosperms: Sporophyte (2n) -----meiosis-----> spores (n) ---> gametophyte: female gametophyte ----mitosis----> egg (n) male gametophyte ----mitosis----> sperm (n) Egg + sperm ----fertilization----> zygote (2n) ----> seed Gymnosperms and angiosperms: no swimming sperm, can reproduce without water, tiny gametophyte, internalization of spore development, have seeds Angiosperm synapomorphy: flowers. Flowers are often hermaphroditic (male and female parts on same flower) Angiosperms are the only plants that make food for their developing embryos and have flowers and fruit Endosperm is the food for the baby, produced through double fertilization Synapomorphy- derived character state uniquely shared by a group of taxa Gymnosperm and angiosperm synapomorphy- seeds, spores and gametes inside, loss of swimming sperm, gametophyte tiny Angiosperm synapomorphy- flowers, fruit, double fertilization Flowers- often hermaphroditic (female and male parts on same flower). Female part: carpel- stigma, style, ovary Male part: stamen- filament and anther (microspore here produces microgametophyte/ pollen) Once pollen leaves the anther and attaches to stigma (usually on a different flower), the sperm that is in the pollen will fertilize the egg to make a zygote and form a seed, and

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the fruit develops all around that seed. The ovary develops into the fruit with the seeds inside. Examples of angiosperms: lawn grass, broccoli, corn, maple tree, sweet potato, rice, apple tree Fruits come from the flower; they are the ovary after fertilization. Fruits protect the seed and aid in dispersal. The fruit does not provide food for the seed The seed holds the embryo (the “baby”) and the endosperm (the food for the “baby” embryo). We eat and get energy from the embryo and the endosperm A corn plant has both the female and male flower. Female flower- the corn cob. Male flower- the tassel at the top of the plant (this is where the male gametophyte/pollen is produced) Some angiosperms have separate male and female flowers (ex: corn), while other angiosperms have male and female parts in the same flower (ex: lilies). Regardless, the female portion has an ovary which holds the female gamete (egg), which is fertilized by the sperm within the pollen. Once the egg is fertilized, it becomes the embryo. So, the embryo is within the seed. All this occurs in the ovary, which then becomes the fruit A corn cob with 100 kernels (seeds) was produced by 200 fertilization events (double fertilization- fertilization of 1) embryo and 2) endosperm) FUNGI They are all eukaryotic heterotrophs Fungi synapomorphy- absorptive heterotrophy (the fungi eat by squirting digestive enzymes onto their food and slurping up the digestive residue- therefore fungi digest food outside of their bodies) and chitin in cell walls (?) Pros of fungi: secrete antibiotics for previously resistant strains of bacteria, cons of fungi: fungal toxin affects many food crops which causes many deaths The mushroom (the reproductive structure of fungus) is most equivalent to the flower (the reproductive structure of the plant) Mushroom also have spores but they are very different from plant spores. Fungi are very different from plants, so they do not have stem, leaf, flower, root, pollen, or seed Monophyletic- (of a group of organisms) descended from a common evolutionary ancestor. A monophyletic group includes the ancestor and all of its descendents Yeast is a group of fungi that share this lifestyle of being unicellular that evolved multiple times. So, yeast do not all share a common ancestor, so “yeast” would not described as a monophyletic group. Instead, they would be described as a polyphyletic group Fungi digest food outside of their bodies (absorptive heterotrophy). Some are saprobesabsorb nutrients from dead organic matter, while others are mutualists Fungi are the principal decomposers of cellulose, lignin, and keratin Fungi absorb carbon and use it to build new cells (they get their energy from other organisms), then return carbon back into the atmosphere as respiratory CO2 (plants and animals respire too!), available for photosynthesis by plants, by consuming plants that have died

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Fungi body is a mycelium composed of hyphae (tubular filaments which have cell walls composed of chitin). Dikarya are a group of fungi that came from one common ancestor (SO they are a monophyletic group) - Saprobes- absorb nutrients from dead organic matter. They return carbon to the atmosphere as respiratory CO2, available to plants for photosynthesis - Predators- attack animals - Parasitic fungi- eat living hosts; fungal hyphae invade plant tissue and animals using fungal spores Fungi can also have symbiotic relationships (living in close, permanent contact) and mutualistic relationships (in which both partners benefit, ex: lichens- fungus + photosynthetic organism); mycorrhizae (symbiotic relationship between a fungus and a plant, fungi hyphae extend the root system and help the plant get minerals and water, and in turn the plant gives the fungus sugars and amino acids. So, mycorrhizae can help reduce the amount of fertilizer needed, they help maintain forests by breaking down organic matter in the soil, and they help increase water absorption in plant/ tree roots) Fungi can reproduce sexually and asexually Asexual fungi reproduction: - Production of haploid spores in sporangia - Production of haploid spores (conidia) at hyphae tips - Cell division by unicellular fungi- fission or budding - Breaking of mycelium Sexual fungi reproduction: (evolved multiple times) - Whereas humans have an egg (n) and sperm (n) that fuse cytoplasms and nuclei to make a diploid zygote (2n), sexually reproducing fungi have hyphal cell one (n) and hyphal cell two (n) that fuse cytoplasms but not nuclei to make one cell with two haploid nuclei (n+n) - Dikaryon: neither diploid or haploid, instead it is n+n for a long period of time. Fungi with a dikaryon stage also have a zygote (2n) stage and a spore (n) stage but not as long Choanoflagellates- closest relative/ outgroup of animals (this is group A on the big phylogeny) Most ancient animals are sponges (porifera) (this is group B on the big phylogeny). They are very similar to choanoflagellates. They have: no symmetry, no tissues, no nervous system, no coelom, no appendages Spores in fungi are used to disperse to new habitats Zygomycota- ex: bread molds- also have n+n life cycle but does not last as long as in dikarya fungi 2 types of dikarya: club fungus and. Reproductive life cycle: Zygote (2n) → Meiosis → Spore (n) → cytoplasmic fusion → fusion of nuclei → back to zygote (all except cytoplasmic fusion occurs in gills of mushroom). The zygote is the only true diploid cell. Hyphae are neither diploid nor haploid, they are dikaryotic (n+n)

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Animal body plan: 5 characters Evolution has shown a trend from absent to present of these characters (ex: sponges have none, humans have all) Symmetry (character states= absent, radial, bilateral) - Radial symmetry- any way you cut will produce a mirror image of the organism. Radially symmetrical organisms tend to be sessile (not locomotive; fixed in one place) and benefit by being able to sense the environment all around them - Bilateral symmetry- you can generate mirror images by cutting from posterior to anterior (from head to tail). This symmetry is associated with cephalizationsensory organs and nerve tissues at the anterior end (head), which makes them locomote in one direction Body cavity type (character states= coelom absent, present) - Body cavities are open spaces within the organs of an animal. They cushion organs and separate external and internal movement. They also act as hydrostatic skeletons (consist of a fluid-filled cavity called coelom, surrounded by muscles). This allows them to burrow and withstand punches Segmentation (character states= absent, present) - Repetition of genetic and developmental packets. It facilitates specialization of body regions and allows animals to alter body shape and control movements precisely External appendages (character states= absent, present) - Outgrowths of the body (they have the same genetic underpinnings) Nervous system (character states= absent, net, present) - Nerve nets- nerve tissues diffused throughout the body (cnidarians have thisthey are group C) - Central nervous system- centralized in anterior side (bilaterians have this) Position 3: Diploblastic (2 tissue layers- so every organism from position 3 has at least 2 tissue layers Cnidarians include anemones, jellyfish, and corals (they are #7 on the big phylogeny) Cnidarian synapomorphy: nematocysts- tightly coiled threads located at the tips of tentacles. It gets discharged to wrap around prey and inject toxins to paralyze prey to eat. Cnidarian life cycle: polyp to medusa (“jellyfish”) forms. Fertilization is often external, with egg and sperm released into water at carefully organized timing Bilaterians- protostomes and deuterostomes- have bilateral symmetry, 3 tissue layers (triploblasts), and body cavity (coelomates and internal skeletons). - Protostomes: (#9 on big phylogeny). Synapomorphies- ventral nervous system (whereas deuterostomes are dorsal); blastopore (the first invagination in the organism) becomes the mouth in development (whereas it is the blastopore becomes the anus in deuterostomes) - Deuterostomes: (#10 on big phylogeny). Comprise 3 clades (monophyletic groups)- echinoderms (sea stars, sea urchins, and relatives), hemichordates, and

chordates (including humans). Chordate synapomorphies: 1) Dorsal and hollow nerve cord, 2) a tail that extends beyond the anus. 3) A notochord Deuterostomes -

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Echinoderms (like starfish) Pentaradial symmetry (in 5s of multiples of 5) No head, so no bilateral symmetry, have an oral side and aboral side (containing the anus) Synapomorphy: water vascular system lead to tube feet Internal skeletons Chorattes 3 synapomorphies: - Dorsal, hollow nerve cord - A tail that extends beyond the anus - A notochord

Matter and Energy Matter cannot be created nor destroyed but atoms can create new forms of objects (all biological processes involve this form change) Matter is an object, atoms in matter can move around and be rearranged Most of the matter in plants comes from gas in the air (atmospheric CO2) Most of the matter in fungi comes from living or dead tissue (fungi are not closely related to plants, they are more closely related to humans. They are heterotrophs, they get their matter and energy from organic compounds) Energy is the ability to do work (not an object; it is a property). Energy, like matter, cannot be created nor destroyed but can also be changed/ transformed into different types (ex: chemical energy from the food we eat into motion, etc.). Thermal, mechanical, and chemical energy are most commonly discussed in biology When an organism eats food (ex: plant), the energy stored in the bonds of the plant will be converted into heat energy (byproduct of digestion), chemical energy stored in other molecules that will be found in the organisms body The only direct source of energy for a plant is SUNLIGHT. Water and CO2 are sources of energy but photosynthesis is an endothermic reaction, so it uses energy, it does not produce energy, same with minerals and nutrients from the soil. Once the glucose molecule is used through respiration, then it can be used as energy, but only molecules that engage in exothermic chemical reactions (produce/ release energy for the organism) are DIRECT sources of energy. Lipids and glucose, in addition to sunlight, are also direct sources of energy

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When a plant or organism dies, nearly ALL of its energy is still within the organism Matter cannot be turned into energy, this is why when logs are burned, almost all of the mass goes into the air (the matter cannot be transformed into heat energy or light energy). Matter remains matter. It remains carbon (just switches form: solid to gas) Matter and energy transformations occur at the same time Burning fat: Mass from fat goes into the air as CO2 as you exhale (about 80%) some of the mass is also lost as sweat (matter is separate from energy so mass cannot be lost as heat energy) In an open system (ex: cage) the cage will weigh less because carbon will be lost by the mouse’s breathing *** whether there is food and water in the cage or not If a person is standing on a scale, over time the weight on the scale will decrease (open system, so breathing releases the CO2 into the air). If it was a closed system, the weight would remain the same Weight decrease is when some fat or glucose is being turned into water and carbon dioxide (respiration) FAT: - Matter: Carbon in air (CO2) - carbon in food - carbon in fat - carbon in air (CO2) - Energy: Energy from the sun (light) - energy in food(chemical bonds) - energy in fat - heat energy, energy in CO2 (chemical bonds) Food- molecules with many C-C bonds that are sources of matter and energy (carbon rich molecules; ex: poop, chicken, fat, glucose). NOT food- carbon dioxide (it is a building block for food- for photosynthesis- but is not food in itself, calcium pills, “plant food,” iron pills, water, nitrate How do you make carbon-rich molecules? = Primarily through photosynthesis (glucose is the food- it has many C-C bonds) SOME of the food we eat is excreted as poop Sunlight is the only direct source of energy for plants (>99%). Less than 1% comes from minerals in the soil, water, and gasses in the air Photosynthesis: Lots of small, low energy molecules (CO2 and H2O) are used to make one large, high energy molecule (C6H12O6- glucose) and some leftovers. Sunlight provides the energy to do work (breaking of small molecules and building the large molecule) The sunlight does NOT make glucose, it just provides energy to make it. Glucose is made from low energy molecules Respiration is the process of breaking down the large, high energy molecule (glucose) to lots of small, low energy molecules as well as energy to do work (stored in high energy molecule). This energy to do the work can be tracked down to the energy from the sun All organisms (ex: fungi, plants, and animals) use carbon as food to gain mass and do so by respiring/ metabolizing their food (metabolize glucose and release CO2) In other words, only plants photosynthesize, cellular respiration (and therefore the production of CO2) occurs in all organisms (plants, fungi, and animals) A plant in an open system will increase mass over time because it is photosynthesizing (taking in CO2 and making glucose) and respiring (converting glucose into tissues). On

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the other hand, animals (ex: turtle) and fungus would lose weight over time because they do not photosynthesize and are only respiring (animals and fungi are heterotrophs so cannot make their own food) Plants assimilate carbon from glucose to grow through digestion, assimilation, etc. So, plants do not get matter from cell respiration ??? Plants are largely made up of cellulose (a polymer of glucose) CO2 is heavier than oxygen so when we exhale and respire we lose more matter (mass) than when inhale, since we inhale and keep oxygen in our body.

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Notes from Matter and Energy Review Quiz: - Coal holds more energy than wood because coal has more chemical bonds than wood - In a sealed greenhouse where plants are growing, the mass of the air will decrease because the plants are adding carbon from the air to their tissue...