Plant Reproduction Lecture Notes (BIOL140B) PDF

Plant Reproduction Lecture 6.2 Lecture 5.1 Review from last lecture: Evolution of land plants. Think of 4 key adaptations allowed different groups of plants to thrive on land. Review from last lecture: Evolution of land plants. Think of 4 key adaptations allowed different groups of pla...

Plant Reproduction Lecture 6.2 Lecture 5.1 Review from last lecture: Evolution of land plants. Think of 4 key adaptations allowed different groups of plants to thrive on land. Review from last lecture: Evolution of land plants. Think of 4 key adaptations allowed different groups of plants to thrive on land. CQ: Which of the following adaptations of land plants allow plants to grow tall? A. Spore in a hard coating. B. Cell walls made with lignin. C. Vascular tissue. D. A waxy cuticule E. Both B & C. CQ: Which of the following adaptations of land plants allow plants to grow tall? A. Spore in a hard coating. B. Cell walls made with lignin. C. Vascular tissue. D. A waxy cuticule E. Both B & C. Review: Alternation of Generations An example from moss (Phylum Bryophyta) of alternation of generations: Discuss: why does moss need to live in a very moist place for its sexual reproduction to occur? Hint: look at the sperm and antheridium. Discuss: why does moss need to live in a very moist place for its sexual reproduction to occur? A: the flagellated sperm needs to swim to the egg in the archegonium (see circle on figure) CQ: Which option best describes the moss gametophyte stage? A.#1 in the picture; haploid. 1 B.#2 in the picture; haploid. C.#1 in the picture; diploid. D.#2 in the picture; diploid 2 CQ: Which option best describes the moss gametophyte stage? A.#1 in the picture; haploid. 1 B.#2 in the picture; haploid. C.#1 in the picture; diploid. D.#2 in the picture; diploid 2 Groups of plants that Orange arrow is time spent as sporophyte; blue is time spent as gametophyte evolved later have a dominant sporophyte generation, while earlier plants have a dominant gametophyte generation. CQ: Which group of plants spends the most time in a sporophyte stage during its life cycle (A-E)? A B C D E Today Past time CQ: Which group of plants spends the most time in a sporophyte stage during its life cycle (A-E)? A B C D E Today Past time Sexual reproduction in plants Haploid sperm (gamete) from one individual + haploid egg (gamete) from another individual = Diploid zygote (embryo)... a seed! Seed Seed plants: Gymnosperms and Angiosperms Seed: Refers to the embryo (a diploid zygote that results from sperm fertilizing an egg). Pinto beans are a seed. This embryo is Edible “pine nuts” are packaged inside a seeds of pine trees. protective coating along with a supply of nutrients. Coconuts are a seed. Sexual reproduction in Gymnosperms (conifers) Basic Flower Structure (Angiosperms) Anthers: where meiosis occurs to produce pollen (haploid gamete). Stigma: the “landing pad” for the pollen (imagine pollen is a helicopter). Style: the “slide” down which the pollen tube will grow, allowing the small flagellated sperm to swim down to the ovule. Ovaries: Houses the ovules. Develops into a fleshy fruit. Ovule: The egg (haploid gamete). Pollination in Angiosperms Pollination: Pollen moves from the anthers of one flower to the stigma of another. Types of Pollination: what carries the pollen? Wind pollination (example: Gymnosperms!) Water pollination (very rare) Animal pollination (the most common form of pollination). Why did flowers evolve? Flowers can lure in animals to carry pollen from the male parts of a flower to the female parts of another. In exchange, the pollinator gets to eat some of the pollen, or gets a nectar (sugar water) snack. What is this type of relationship between two different species called? Why did flowers evolve? Flowers can lure in animals to carry pollen from the male parts of POLLEN a flower to the female parts of (SPERM) another. In exchange, the pollinator gets to eat some of the pollen, or gets a nectar (sugar water) snack. What is this type of relationship between two different species called? MUTUALISM! It is estimated that between 60 - 80 % of globally important food crops rely upon animals for pollination. Insect populations, especially bees, are declining dramatically worldwide. Are the bees okay? No. However, honey bees (Apis mellifera) are not an endangered species. Honey bees are livestock not wildlife. But they are very important! Several bumblebee species are endangered. What can you do? Avoid spraying pesticides in your home yard or garden. Buy pesticide-free produce when you are able. Provide habitat for native bees in your home or work place, such as Mason Bee (Osmia sp.) nests. Don’t keep a grass lawn - turn it into bee food ! (flowers) CQ: What type of ecological relationship is animal pollination? A. Usually a mutualism; sometimes a type of exploitation (+, minor -) B. Always a mutualism. C. Always exploitative (one species benefits, the other is somewhat harmed). D. Usually a parasitism. CQ: What type of ecological relationship is animal pollination? A. Usually a mutualism; sometimes a type of exploitation (+, minor -) B. Always a mutualism. C. Always exploitative (one species benefits, the other is somewhat harmed). D. Usually a parasitism. Wait, whaaaat? That’s right! Sometimes pollination happens in a way that does not benefit the animal at all. Meet the Hammer Orchid, that tricks male wasps into “mating” with it by pretending to be a female wasp! https://www.youtube.com/watch?v=mNf9lp9EXHc&t=55s After pollination, a pollen tube forms when pollen lands on stigma What are you eating? The flesh of fruits comes from the ovaries of the flower Sexual reproduction in Angiosperms (flowering plants) SEED! CQ: What process allows the single-celled, diploid zygote to form a multicellular, diploid embryo? A. Meiosis cell division. B. Mitosis cell division. C. Sexual reproduction. D. Asexual reproduction. E. Pollination. ? CQ: What process allows the single-celled, diploid zygote to form a multicellular, diploid embryo? A. Meiosis cell division. B. Mitosis cell division. C. Sexual reproduction. D. Asexual reproduction. ? E. Pollination. CQ: Which of these was produced by meiosis? A. Pollen grain B. Seed C. Fern spore D. Flower ovary CQ: Which of these was produced by meiosis? A. Pollen grain B. Seed C. Fern spore D. Flower ovary Anatomy of a seed Embryo: The diploid zygote formed by fertilization of the egg by a sperm. Where do different fruit types come from? Food plants are subject to many stressors Humans use 2 main strategies to reduce these stressors in our crops, increasing food yield. Artificial Selection and Domestication Selective breeding by humans to emphasize desired traits is known as artificial selection or domestication. Example: dogs. Most wild ancestors of domesticated crops look very different! Wild plant similar to ancestor of crop on the left, domesticated crop on the right; Watermelons Banana Strawberry Cabbage Maize (corn) shares a common ancestor with Teosinte (a wild grass) Domesticated more than 8,000 years ago in Mexico near modern Mexico City. 59 Indigenous varieties of corn in Mexico today. Ancient cultures of Mexico used selective breeding technology to pick individuals in each generation of maize with juicier kernels, and selectively bred those individuals until over time… yummy maize! CQ: How is artificial selection different from natural selection? In artificial selection, … A.Selection is for those traits that improve the fitness (reproductive success) of the organism in natural conditions. B.Humans, not natural conditions, select for the traits that will be passed on. C.Selection is not necessarily for traits that improve the fitness of the organism under natural conditions. D.A & B E.B & C CQ: How is artificial selection different from natural selection? In artificial selection, … A.Selection is for those traits that improve the fitness (reproductive success) of the organism in natural conditions. B.Humans, not natural conditions, select for the traits that will be passed on. C.Selection is not necessarily for traits that improve the fitness of the organism under natural conditions. D.A & B E.B & C Pugs have respiratory problems because of human selection for their short snout! Humans use 2 main strategies to reduce these stressors in our crops, increasing food yield. Genetically Modified Organisms (GMOs) in Food A GMO crop has had genes from another organism inserted into its DNA to improve yield. For example: Bt Corn has had a gene from the bacteria Bacillus thuringiensis added to its DNA. Now, it can produce a chemical that kills certain insect pests.  Corn Garbanzo beans Papaya Squash Cotton Potato Apples Others... Assignments Textbook Reading: Ch. 30.3 - 30.4. (Plant diversity 2) Ch. 38.1-38.3. (Angiosperm reproduction and Biotechnology).