Plant biology exam 3

What can be done to conserve grasslands

- Some conservation plans are already in place; many are involved with increasing awareness of problem and lobbying large firms and companies to reduce their land use or use it more responsibly - US gov has also set aside areas that are to be protected that may not be developed or used in any way that has long term effects on the flora and fauna -Future, more efforst to replant grasses in the area and try to restore the land that has been lost

Taiga

-Canada -South of Tundra -Long winters, brief hot summers -25-100 cm water per yar -vegetation is mostly conifers, some birch, aspen and herbaceous perennials -angiosperms occur where there are breaks in conifers and they are exposed to light

Biome

Def - similar ecosystems considered on a worldwide scale Interactions - could study the change of a biome and the ecosystems within over time, or the role of competition between two parties example - how has global warming/cooling cycles affected biome location over time?

Ecosystem

Definition - a system involving interactions of living organisms with one another and with the non-living environment Types of interaction - large focus is on functionality and mechanisms that maintain the structure and services of an ecosystem - think production of biomass, decomposition, trophs, etc. Example - insects and fungi breaking down plant matter into nutrient rich soil that allows more plants to grow

Population

Definition - group of organisms, usually the same species, in the same area Type of interaction - population size and density over time and space, can look at local pops, sub pops, or global Example - impact of differently sized leaves when competing for sunlight on individual plants

Effects of human activities on grasslands

Grasslands are home to many different species of grass, so they are naturally home to large grazing animals like buffalo Humans have developed these areas, and species like buffalo have died. -Humans have cultivated the area to the point that buffalo can no longer graze and have died out. On top of that, humans have hunted them - Today, large portion of grasslands have been converted to large crop or forest plantations -Even worse, its been destroyed to make way for urbanization or for energy and mining development. -Remainder is grazed upon by a large amount of animals; high density of animals in such a small space means that grass does not have time to regrow -resulted in lower biodiversity, loss of habitat, desertification

Pick biome at risk and say characteristics

Grasslands in NA are found throughout Midwestern US -Usually found in the interiors of continental margins and integrate with forests, woodlands, or deserts at the margins, depending on precipitation patterns. -Relatively low amount of rain - 25-100 cm annually -Temperate climate -Vegetation dominated by grasses -NA grasslands are known as prairies, and grew on fertile soil - grasses in praries can grow to 2 meters, up to 3 meters in wet years - lots of species of wildflowers - up to 50 in one hectare

Describe ways in which conifers promote outcrossing

Have several ways to overcome distance and mate with distant members of species -Distribution of cones: female cones are located in upper branches of tress while pollen cones are near bottom. Eliminates chances of pollen cones falling directly onto seed cones and self-fertilizing. Also unlikely for wind to blow pollen directly upwards onto cones - will probably travel some distance before reaching a cone -Monoecious conifers may also stagger production of cones so they are not active at the same time on the plant - temporal separation -Dioecious --> male and female cones are on differently sexed trees, so it is impossible to mate with itself

World Nitrogen Cycle

Like carbon cycle, N cycle relies on plants, animals, decomposers, and environmental factors - Most mitrogen in organisms is in the protoplasmic proteins of cells - decaying plant and animal matter, including waste, has nitrogen that decay bacteria use to produce ammonia and other nitrogenous compounds -Plants uptake nitrogenous compounds, including ammonia and nitrates, through roots that they use to produce Amino Acids and chlorophyll -Some plants develop root nodules where nitrogen-fixed bacteria live and multiply, providing plants with direct access to N -Nitrite bacteria converts NH4 to nitrite -Nitrate bacteria converts nitrite to nitrates -Animals eat plants so there is constant flow of N from dead plants and animal tissues and waste into the soil, and from soil back into the plants. -Large amounts of N lost to fires, soil erosion, and denitrifying bacteria that uses nitrates for respiration -However, some N returned to soil through precipitation because of nitrogen gas fixation to nitrates caused by lightning and through volcanic activity

Under what conditions do seritonous cones open?

Lots of triggers, including but not limited to - death of parent plant or branch (necriscence, can be caused by fire) -wetting (hydriscence) -warming by sun (soliscence) -drying atmosphere (xeriscence) -Fire/heat (pyriscence) -fires followed by wetting (pyrohydriscence) pine cones usually open after a fast and very hot forest fire --> resin melts

Choose one of the major groups, extinct or extant, that has been proposed as an ancestor and give evidence for or against it

Lyginopteridopsida - subset of the larger group called pteridosperms (seed ferns). These are not actually ferns, but resembled them and had seeds. - we know angiosperms are at least as old as the mid-early Cretaceous (around 125 mya), but may have evolved earlier -earliest known angiosperm is Montsechia vidalii (aquatic plant from 125-140 million years ago). -Lyginopteridopsida went extinct or evolved around the triassic period (just before jurassic). -Lygino doesnt necessarily have flower parts (petals, etc) but may have had some flower morphology -Pollen was also present during triassic period -Ovules enclosed in a carpel and stamens with two pairs of pollen sacs are key identifying parts of early angiosperms -Cupules of lygino plants are unique to this group, and protected the ovule as it matured. Analogous to carpels enclosing angiosperm seeds (STRONGEST ARGUMENT)

Mountain/Coastal

- Pacific NW US -Dry Summers but lots of rain in rest of year -Fog and mist -250 cm of rain per year -mixed vegetation, but not all mixed together; clumped together into groups (conifers in one place, birches in another, etc) -Conspicuous zonation with altitude

What characteristics do angiosperms have that make them so dominant?

- advanced vessel system for conducting water allows them to deliver water to tissues more efficiently than other plants. Gymnosperms, for example, only have tracheids. Tracheids do not have perforations in their end plates and water can only pass through thracheid pits. Tracheids originate from single cells and are relatively thin. Angiosperms have tracheids as well as vessel elements. Vessel elements are better at conducting water since they are wider, made up of clumps of cells, and have perforated end walls that allows water through more easily. Vessels are considered more advanced than tracheids -angiosperms produce flowers, which have a significant advantage for pollination. Flowers have adapted to their specific environments to be as appealing as possible to pollinators in the area (insects, birds, bats). Specific targets for pollination, and reduces the amount of pollen that needs to produced in order to achieve cross-pollination (since other plants just put out a lot and hope it reaches another plant eventually). Additionally, many plants have co-evolved with insects and other pollinators to increase effieciency as much as possible -unique structures for seed dispersal - fruits can be eaten bu animals or insects. After digested, the seeds are spread throughout a larger area. Also have adapted fruit that allow for dispersion by wind or other natural elements -Doubly fertilized, which produces endosperm, the nutritious tissue that feeds developing embryo --> is able to last for longer and travel further

What are the characteristics of biomes where serotinous cones are found

- found in biomes where environment shifts between unfavorable and favorable conditions for germination -favorable conditions: pine - cones open up and seeds drop out; angiosperms - pods open up and seeds drop out Found in Mountain/Coastal, Taiga, and Chapparal

What did Darwin mean by "abominable mystery"?

-Darwin was deeply disturbed by what he perceived to be an abrupt origin and highly accelerated rate of diversification of flowering plants in the mid-Cretaceous era. Flowering plants suddenly appear in the early cretaceous (125 mya). There are a few plants in Jurassic (210 mya) and Triassic (240 mya) that have similarities to angiosperms, and many from these periods have pollen grains similar to extant angiosperms. This led Darwin to believe that there was a long, gradual and undiscovered pre-cretaceous era of angiosperms on a lost island or continent. He also took refuge in the possibility that a rapid diversification of flowering plants in the creaceous might, if real, have a biological explanation involving coevolutionary interactions between insects and angiosperms. But becuase of the lack of evidence that points to one ancestor, we still are unsure of what angiosperms evolved from.

World Carbon Cycle

-Earth has finite supply of elements and resources, need to recycle them in cycles that involve inorganic and organic forms Carbon cycle -large amounts of carbon are stored in atmospheres and large bodies of water as carbon dioxide -Co2 enters atmosphere through burning of forests, fuelwood, and organic debris -Also through combustion of fossil fuels for vehicles, electricity, heat. Fuel is made up of coal (formed from decomposition of dead organisms and waste) and oil and gas ( formed from organic sediments) -Cellular respiration of animals from all organisms produces CO2 - Decomposers are important because they break down the remains of dead plants and animals, producing a large percentage of CO2 -Plants use photosynthesis for energy; utilize CO2 in air to produce carbon-containing carbohydrates (with O2 and water) -The carbohydrates are part of the terrestrial and aquatic food chain - stored in animal and plant tissue as well as animal waste -CO2 used by places is replaced mainly through respiration, particularly decomposers -In this way, a cycle is formed in which carbon cycles between an inorganic form, CO2, and organic forms, such as the carbohydrates in plants.

Chapparal

-Socal and mexico -Hot and dry summer, cool and wet winter -basically all shrubs -spiny plants -not many deciduous tress since it does not get cold enough to drop leaves - a few evergreens

Conifer life cycle (steps)

-Sporophyte produces 2 types of structures: woody seed cones and and smaller soft pollen cones. -pollen cones have paper scales called microsporophylls --> at base is microsporangia --> make microsporocytes --> undergo meiosis to make 4 haploid microspores Megasporophylls are seed cone scales that are modifed branches, have ovules at base with megasporangia --> product megasporocytes --> undergo meiosis to get 4 haploid megaspores --> 3 disintegrate over time, leaving one to grow into female gametophyte --> differentiates into archegonia, with a single egg microspores mature into pollen grain with wings --> pollen grain grows an elongated pollen tube --> seed cone opens scales --> wind carries pollen into spaces --> pollen drip sticks to pollen near opening of archegonia --> fluid slowly evaporates, bringing pollen in --> scales close again --> 1 month later, megaspore development --> 1 year later, gametophyte and archegonia are mature pollen tube grows --> generative cells and tube cells enter --> generative cells become spermatogenous cells --> become 2 sperm cells withouth flagella --> tip of pollen tube makes contact with archegonia --> sperm are released and one unites with egg to form zygote, other dies zygote grown within female gametophyte and develops into embryo --> embryo uses gamteophyte for food --> embryos grow at end of suspensor cells attached to rosette cells --> embryo matures and integument hardens into seed coat --> thin membrane around cone scale develops into wing, carries seed away --> seeds germinate and give rise to seedling

Explain what happened to tomato in Aerogarden

-Tomato plant began as a few fertilized seeds in the soil -embryos inside were dormant -Once conditions for germination were met (soil damp not wet, buried shallowly enough that it still has access to oxygen, 70-80 degrees F, and 14-16 hours of direct sunlight), the embryo within the seeds resumes development -Seed was activated by water, or undergoes imbibition, cytoplasm rehydrated and enzymes activate -gibberellins convert proteins to AAs for quick reassembly -amylase converts starch to sugar for immediate energy use (amylase stimulated by gibberellins) -Fats and oils converted to soluble compounds -Respiration increases, provides embryo with energy -ATM repairs DNA damage that occurred during dormancy -Rapid cell division takes place and embryo expands -Cell elongation after gibberellins are produced, cell walls are stretched, seed coat breaks open -Cytokinins initiate cell differentiation -radicle grows out of seed. Radicle extracts water and minerals from the soil for the plant -top at radical loop elongates and becomes the epicotyl of the plant -shoot begins to form a hook, pointing down towards the seed -after reaching surface, the hool straightens and the cotyledons are pulled into air -seed coat cracks and cotyledons separate into leaves -seedling grows and shoot will bud off and eventually forms true leaves - radicle becomes primary root and secondary roots branch off -gibberellins at tips of the stem, causing it to grow quickly

Problems with definition of climax community

-climax community as a stable, unchanging community until another disturbance is flawed - no ecological community stays entirely the same, even after succession ends - other organisms may develop in the area long after succession ends, and seasonal changes along with other short-term events can cause drastic changes -an area would have multiple climax communities after succession, and each would look very different - Hard to define one community as a snapshot ending to succession; instead, climax community could be defined as a stable environmental state in which all organisms that are indigenous to an area would be able to successfully establish and survive, or a "least common denominator" of all soil/organisms that live in an area over the course of a year

Fruit Dichotomous Key

1. Multiple/aggregate or not 2. drupe or not 3. fleshy or dry 4. pome or not 5. berry or hesperidium 6. splits or not 7.splits at seams or capsule 8. follicle or legume 9. nut or grain 10. multiple or aggregate

Methods for seed dispersal that involve animals. Include how animals benefit if applicable

1. birds, mammals, and insects will eat the fruits or seeds and disperse the seeds. -some animals, seed passes through digestive system unharmed and deposited far from original plant -especially relevant with fleshy, bright colored and sweet fruit (attract animals) -Some fruits that birds eat contain laxatives that speed the passage of the fruit and its seeds through the digestive tract -process can also be prolonged - ex Galapagos turtles, seeds stay in GI tract for 2 weeks or more 2. Rodents and other small animals may gather seeds and nuts to store for winter and bury them, but may not find all of them again, allowing them to germinate later 3. Some birds carry away nuts and fruits dropped in flight by other birds - even more diversity in motility 4. Trilliums and bleeding hearts have appendages on their seeds that contain oils attractive to ants who carry the seed to their colonies and strip away the appendages but do not harm the seed -ant benefits because they use the oils to feed larvae animals benefit because fruit/seed provides nutrition for them or their offspring 5. Use animals fur or feathers as a behicle for dispersal - may attach directly through special adaptations. Ex bedstraw and bur clover fruits have small hooks that catch on the fur. Unlike other methods, does not benefit animals

Conifer Life cycle (graph)

2 sporophytes Sporophyte, woody female seed cone and cluster of male pollen cones, megasprorocyte with ovule and integumen, microsporangia w microsporocyte GOES to n microspores --> pollen grain w wing, generative cell --> pollen tube with spermatogenous cell --> pollen tube wih sperms integument and megaspores --> archegonium iwth eggs and pollen drop --> eggs without pollen drop come together to form zygote, 2n zygote --> developing embryo on end of suspensor and rosette cells surrounded by wall --> ebryo inside seed coat --> seed with wing --> seedling

Pome

A simple fleshy fruit whose flesh comes from the enlarged floral tube or receptacle that grows around the ovary. They have an endocarp around the seeds that is paper or leathery. Example - pears

Community

Def - collective term for all the living organisms sharing a common environment and interacting with each other Type of interaction - interactions between species and populations within the same geographic location example - predatory bird population in Yellowstone before and after the re-introduction of wolves

Habitat

Def - place or environment where a plant or animal naturally lives and grows; specifically, the environmental conditions that organisms live in (biotic and abiotic) Interaction - specific type of ecosystem that a population/community/individual resides in is important - where it lives, finds food, and mates Example - impact of small rodents, birds or other animals living in trees - help, hurt, or no effect

Nut

Dry indehiscent fruit with one seed. Does not split at maturity. Hard and thick pericarp that is fused to seed only at bottom and can be taken off, and contains a cluster of bracts at its base

Angiosperm life cycle (explanation)

Flower develops bud-->diploid megasporocyte differentiates from one of the cells in the ovule (megasporangium with 2 integuments) --> undergoes meiosis to form 4 haploid megaspores --> 3 disentigrate --> 3 successive divisions of the remaining nucleus produce 8 haploid nuclei --> nuclei form a megagametophyte (aka female gametophyte of embryo sac) --> small pore (micropyle) develops at one of the ends of the ovule --> in megagametophyte, 3 nuclei remain on each far end of the cell --> 2 remaining nuclei in middle of cell are called polar nuclei (central cell nuclei) --> in group of cells near the micropyle, one will develop into the egg --> other two assist in guiding the pollen tube to the egg anthers, male gamete forms -->microsporangia differentiate from main mass of cells to produce microsporocyte cells --> meisosis, get 4 microspores --> as anther matures, adjacent pairs of chambers with the microspores fuse, leaving 2 chambers --> microspores become pollen grains through mitosis and development of a 2-layered wall --> pollen has generative cells and tube cells --> nucleus of generative cell divides to produce two nuclei that are surrounded by a plasma membrane (forms haploid sperm) --> pollen grain with 2 sperms is the male gametophyte. pollination is transfer of pollen grains from anther to stigma by insects, birds, wind --> after pollination, pollen grain grows a pollen tube that grows down beetween cells of stigma and style until it reaches micropyle of ovule --> one sperm fertilizes egg and forms zygote, other unites with the polar nuclei to form a triploid endosperm nucleus that divides to form endosperm--> ovule develops seed coat from integuments and endosperm serves as food from embryo --> fully developed seed Ovary of the pistil forms into a fruit --> seeds are dispersed by animals or wind --> seed germinated --> sporophyte develops --> mature sporophyte

aggregate fruit

Fruit derived from a single flower with multiple pistils. Each pistil forms a small fruitlet, and they fuse together to form the mature, single clustered unit. Ex - raspberry. In strawberries, the cone-shaped receptacle becomes fleshy and red while pistils form small dry indehiscent fruit on the surface

Multiple fruit

Fruit formed from multiple flowers in a single inflorescence. Each flower has its own receptacle, but as flowers mature separately into fruitlets, they merge together to form one fruit. Ex pineapple

How could coevolution with insect account for the rapid speciation during the Cretaceous

Many angiosperms rely on bugs/insects for reproductive processes -vary from needing digestion of seeds before germination to needing bees to physically carry pollen from plant to plant -as insects diversified, so did the plants to keep up -plants need to have markers that will attract insects and animals to pollinate the flowers -to stick out, could have a brighter flower that is noticed so that butterfly pollinates it -for other plants, the bright colors are a disadvantage and need white flowers to stand out at night -some may need a strong smell to attract insects or ward off other animals -some sizes/shapes may be advantageous as well -plants that dont rely on insects dont look pretty or smell good

Pollination strategy for conifers which uses pollen more efficiently

Much of the pollen that is released never reaches other trees - theres a lot of waste. Efficiency could be improved by copying the strategies that angiosperms use. They could change the color of cones to be more attractive to pollinators, or exude a sweet smell. Seed cones could similarly be changed to allow for pollen to be transported into them. If the conifer's sap was sweet, it could attract insects that accidentally move some pollen.

Advantages of seeds over seedless plants

Seeds: -Seed coats protect seeds -supply of nutrients for the embryo when seed germinates -seeds can last for years (can wait for better weather to germinate) -Seeds can be spread further (last longer) -Can potentially survive fores Pollen/ovules: -Water isn't needed for fertilization -Pollen is enclosed in a capsule and can be spread further than sperm of seedless plants. Light enough for wind and animals to carry -Ovules more protected Non-reproductive: -allow seeds to reach further inland, into harsher terrains with less competition -risk of infection from growing in monoculture clusters is reduced -more xylem than seedless plants - better water moving -can produce secondary xylem -helps with water transpiration and structure

Process of primary succession on bare rock. Include examples of disturbance which cause this and typical definitions of primary succession and climax community

Primary succession - process of colonization by a pioneer species in an area that was previously devoid of life and soil -After natural event such as glacial erosion or volcanic eruption wipes out plant life, plants must begin process of colonization - Lichens and mosses produce acids that can weather rock and give a perforated surface to establish on - Lichens and misses stick out of rock and trap dust and debris --> form a thin layer - Weathered rock, combined with dust and debris, and some mosses resistant to desiccation produces a thin layer of soil, allowing for plants to establish themselves - Lickens and mosses die, providing organic material in the soil precursor for the new plants to grow - orgnanic material continues to grow and die, over time collecting dust debris and other materials - Repeats until a thick layer of soil forms, allowing for small vascular plants to take root - Rock forms cracks in surface due to alternate thawing and small levels of water erosion --> allows vascular plants to take deeper root - Roots open cracks further, adding rocky element to soil - Roots stabilize soil layer and prevent erosion - roots hold water in soild and add nutritional value - vascular plant dies and adds organic matter to soil. Eventually larger vascular plants take root in soil - Climax community is reached when soil and organisms living in it remain stable and same until another disturbance takes place

Advantages and disadvantages of seritonous cones

Pros -Seeds are protected until conditions are right for germination -stored seed bank for species when a soil seedbank is not possible -if seeds are released after a fire, less likely that seed-eating animals will be around Cons -conditions don't occur very often -seeds must remain viable for a long time -cones need water to keep seeds vaible -small rodents will eat pine cones and seeds inside them -some species have non serotinous ways of reproducing to combat this

How does answer change with secondary succession

Secondary succession - there is already an existing layer of soil - process occurs faster since organic and inorganic materials do not need to build up over time and create the soil necessary for reestablishing plants - larger vascular plants can form immediately after the disturbance - Occurs after disturbances with less erosive action, like fire and extensive logging

serotinous cones

Seed release due to environmental conditions rather than seed maturation

Capsule

Simple dry dehiscent fruit that has at least 2 carpels and splits in a variety of ways. -split along partitions in carpels -split through cavities in carpels -form a cap that pops off and releases seeds -forms pores that release seeds when fruit is shaken ex. orchid

Legume

Simple dry dehiscent fruit that splits along 2 seams or sides to expose seeds. Example peas. Peanurs are atypical in that they develop underground and pericarp is broken open by bacteria rather than an active splitting mechanism

Follicle

Simple dry dehiscent fruit that splits at maturity. Splits along one seam or side to expose seeds. Example - milkweed

Caryopsis

Simple dry indehiscent fruit with one seed that is tightly bound to pericarp and cannot be separated from it. AKA grain. ex rice

Berry

Simple fleshy fruit with more than one seed (usually - exceptions avocados and dates). Form a compound ovary. Has a thin skin and are relatively soft, entire pericarp is fleshy and hard to distinguish mesocarp and endocarp. Example - tomato Some berries form from internal ovaries, so flesh of fruit is also made up of accessory tissue. They may have scars or marks at tip from where external accessory tissue was attached - example blueberries.

Hesperidium

Simple fleshy fruit, a type of berry. Has a thick leathery rind that contains oils. Ovary walls are lined with hairs called pulp that become sac-like and fill with juice as fruit develops. Example - orange

Drupe

Simple, fleshy fruit with a single seed enclosed in a hard, stony endocarp called a pit. They usually develop from flowers with a superior ovary containing a singular ovule. Mesocarp may not always be fleshy (ex, coconut has a fibrous husk made of the mesocarp and exocarp). Example - peach

Intern at CBG. What potential problems with bees bothering the women?

The women of the RHS have a very specific outfit, with bright red hats and purple clothes for women over 50, and pink hats and lavendar clothes for under 50. If flower beds match, they would be a lot of purple and red flowers. Since the party is in summer, there will be lots of pollinators like bees, butterflies, and hummingbirds around the area that are attracted to the bright flowers. Pollinators are drawn to color, and each has a preference for a certain color. Insects are also drawn to the smell of nectar. Bees are drawn to colors in blue to violet range, and butterflies are attracted to bright colors like red, yellow, orange, pink, purple. Hummingbirds are attracted to bright colors with a special affinity for red flowers. Shape of flower could also attract hummingbirds. All pollinators will be drawn to the women, with their bright clothing and potentially sweet smelling perfume. They will be confused for flowers, especially with the extravagant hats. The pollinators would try to land on the women and disturb them. If some are allergic to bee venom this could be very dangerous. Innocent pollinators may also get hurt.

Angiosperm life cycle (graph)

in book