Plants and Fungi 2025 Lecture Notes PDF

Unit 1: Evolution and Biodiversity What is Evolution? Phylogenetic Trees Evolution of Populations...

Unit 1: Evolution and Biodiversity What is Evolution? Phylogenetic Trees Evolution of Populations Origin of Species History of Life Biodiversity: Bacteria, Archaea, Protists, Fungi & Plants The Tree of Life/ The Phylogeny of Life Spring 2025 Diversity of Life: Plants & Fungi 90486  Plants and Fungi Key points from today’s lecture 1) Fungi are not plants. Fungi are heterotrophs that feed by absorption; they lack chlorophyll. 2) Fungi have radiated into a diverse set of lineages. They play key roles in nutrient cycling, ecological interactions, and human welfare. Mycorrhizal fungi form mutualistic symbioses with many plants. 3) Land plants evolved from green algae. Challenges of a terrestrial environment include gravity, environmental fluctuation, and water availability. Early benefits include reduced competition, herbivory, and parasitism. 4) Seeds and pollen of gymnosperms and angiosperms are key adaptations for life on land. 5) Key adaptations of angiosperms include flowers, fruits, and double fertilization. Flowering plants reproduce sexually, asexually, or both. Many species have mechanisms to avoid self-fertilization. 6) Angiosperms form many symbiotic relationships with animals to provide pollination, seed dispersal, and maintenance. Synopsis for today Understand the main characteristics of fungi and plants Recognize the important roles fungi and plants play in ecosystems Recognize the important relationship that humans have with a variety of fungi and plants Chapter 29: Focus on Concepts 29.1, 29.3 Chapter 30: Focus on Concepts 30.1, 30.3, 30.4 Chapter 31: Focus on what we cover in class  The Origin of Multicellularity Evolution of eukaryotic cells = greater range of unicellular forms Second wave of diversification occurred with evolution of multicellularity = algae, plants, fungi, and animals – Multicellularity evolved multiple (~20+!) times within diverse eukaryotic lineages => Convergent evolution of multicellularity is reason protists are para/polyphyletic  Euglenozoans Today’s Focus: Plants & Fungi Forams Diatoms Both are Eukaryotes - Note the relationship between plants & fungi Domain Eukarya Ciliates Red algae vs. fungi & animals! Green algae - Look at the placement of the protists in this Plants phylogeny! Tubulinids Fungi Plants Animals - Green algae (charophytes) are the closest Euryarcheotes Archaea relatives Domain Thaumarchaeotes COMMON Crenarcheotes - Algae and plants share similar traits ANCESTOR OF ALL LIFE Proteobacteria - Plants did not evolve from modern green (Mitochondria)* algae; they share a common ancestor Domain Bacteria Chlamydias Spirochetes - Plants moved from the water to land; most Gram-positive bacteria now are terrestrial but some are aquatic Cyanobacteria (Chloroplasts)* 6  Why should you care about plants? Base of terrestrial food webs Agriculture Potato field, Netherlands “The invention of agriculture, which depends almost entirely on the cultivation and harvest of seed plants, was the single most important cultural change in the history of humanity…”  Why Are Plants Important? abundant, complex living organisms oxygen = byproduct of photosynthesis ultimate source of energy for most land 450 Gt of Carbon! animals sources of medicines & “recreationals” (e.g., caffeine) absorb CO2, some concentrate heavy metals Amazon Rainforest 2 Gt of Carbon… fabrics & textiles paper “plastics” (polymers) Bar-On et al. 2018 & Vox  Fighting “Plant awareness disparity” humans rely on plants: oxygen, medicine, food, shelter, clothing not simply “background” many species face extinction despite being potential sources of undiscovered medicines… Advantages to moving onto land 1. Fewer herbivores, parasites, & competitors 2. Increased sunlight 3. More CO2 4. Rich in mineral nutrients  Challenges of moving onto land 1. Gravity 2. Scarcity of water 3. Environmental fluctuations Key traits (adaptations) have evolved in land plants (but not in charophyte algae) & have contributed to their success  Land Plants Note that bryophytes and seedless vascular plants are NOT monophyletic! Seed plants are monophyletic. Nonvascular Plants (Bryophytes) vs. Vascular Plants Vascular Plants: Seedless Vascular Plants vs. Seed plants Seed plants: Gymnosperms & Angiosperms 12  Life on Land One Key Adaptation for Life on Land Initial Benefits of Being on Land Sporopellenin: Unfiltered sunlight Durable polymer that prevents zygote Plentiful CO2 dehydration in charophytes Mineral-rich soil Similar to modern casing of plant spores Few herbivores or pathogens Initial Challenges of Being on Land Terrestrial environments are dry No structural support against gravity There are a handful of derived plant traits that help the plant survive and reproduce on land. 13  Derived Traits of Land Plants: #1 Alternation of Generations Alternation between two multicellular generations: - Gametophyte generation (haploid) - Sporophyte generation (diploid) Spores develop into gametophytes  Derived Traits of Land Plants: #2 The embryo depends Multicellular, dependent embryos on the parent –why plants are called embryophytes Parent provides embryo nutrients via placental transfer cells 15  Derived Traits of Land Plants: #3 Walled spores produced in sporangia Sporangia: where the sporophyte produces spores The sporopollenin of spore walls helps when the organism is in harsh environments 16  Derived Traits of Land Plants: #4 Multicellular gametangia 17  Derived Traits of Land Plants: #5 Apical meristems Apical meristems have repeated cell division, allowing for continual growth in length by the plant Apical meristem cells differentiate into many tissue types  Additional Derived Traits of Land Plants Mycorrhizae (symbiotic File:Kale2.jpg association Cuticle between fungi and plants); help acquire nutrients Stomata (allow for gas exhange) Cuticle (waxy covering of epidermis) 19  Additional Derived Traits of Land Plants Secondary compounds Protect against herbivory, Recruitment of wasp Wasp parasites, pathogens lays eggs Synthesis and release of chemical attractants Plant cell Damage to plant and chemical in caterpillar saliva Signal transduction pathway 20  Additional Derived Traits of (some) Land Plants Vascular Tissue: Tracheary elements (xylem): dead & hollow, H2O conducting Sieve elements (phloem): living, dissolved sugar conducting Allowed plants to get taller!  Secondary Compounds Alkaloids: Some toxic, bitter, stimulants, Tannins: Some bitter, repel predators, and/or analgesics and/or antioxidants File:CoffeeBerry.jpg File:Canelle Cinnamomum verum Luc Viatour crop1.jpg File:Papaver somniferum 01.jpg Coffee (Caffeine) Poppy (Morphine) Red wine; red beans; cinnamon Terpenes: Strong smell, repel predators, Flavonoids: Some bitter, plant pigments, and/or medicinal and/or antioxidants File:Osmeterium File:Grapefruit Schnitt 2008-3-3.JPG File:ARS red onion.jpg File:Résine.jpg File:Aromatas.JPG cropped.jpg Essential oils; resin; turpentine; caterpillar instar Grapefruit; red onion; dark chocolate 22  Secondary Compounds Terpenes/Terpenoids largest group of secondary metabolites (~22,000!) hydrocarbons, variations on isoprene Along with water vapor, makes the Smoky Mountains, “Smoky” & Blue Ridge Mountains, “Blue”… …and why paintings have a “blue” landscape effect in distance (aerial perspective) Gametophyte-sporophyte relationships 24  Evolution of Seed Plants Seeds are ‘mobile wombs’ that enabled seed plants to become critical producers Gymnosperms: Gymno = naked + sperm = seed Angiosperms: Angio = container (fruit) + sperm = seed 25  Shared Characteristics of Seed Plants 1. Reduced gametophytes (extremely 2. Heterospory (produce two types small; develop in the walls of spores; of spores, developing into male or gametophyte is protected & obtains female gametophytes) nutrients from sporophyte) Megasporangia produce megaspores (give rise to female gametophytes) Microsporangia produce microspores (give rise to male gametophytes) Ferns, on the other hand, are homosporous. They produce one kind of spore, which usually produces a bisexual gametophyte. Ferns are not seed plants 26  Shared Characteristics of Seed Plants 3. Ovules & egg production 4. Pollen & sperm production Advantages of the seed: Contains embryo & food supply in protective coat Allows long-distance dispersal & long-term dormancy as needed 27  Gymnosperms Gymnosperms have “naked seeds” exposed on sporophylls that usually form cones. Most gymnosperms are cone-bearing plants called conifers, such as pines, firs, and redwoods 28  Angiosperms Seed plants that produce flowers and fruits Flower: Structure for sexual reproduction - Pollination by animals (insects, birds, etc.) or wind - Evolution of angiosperms impacted by pollinators Flower Anatomy and herbivores Herbivore Pollinator Fruit structure: Protects Structure aids in seed dispersal dormant seeds 29  Products from Seed Plants angiosperms provide ~80% of human calories: Wheat Rice Maize Potatoes Cassava Sweet potatoes Anyone want a warm beverage? What about a warm fire? Is this lecture giving you a headache? Aspirin derived from willow tree 30 Threats to Plant Biodiversity Deforestation Invasive herbivores & pathogens 31  Review & practice Draw the generalized plant life cycle – How does cycle differ across taxa? Challenges of a terrestrial environment List key adaptations of – Land plants – Vascular plants – Seed plants  Fungi Eukaryotic Very important for terrestrial ecosystems – Organic material decomposition – Nutrient recycling Most are multicellular Heterotrophs that feed by absorption – Absorb nutrients from outside bodies Most have cell walls containing chitin Propagate by producing spores Consist of decomposers, parasites (absorb nutrients from living hosts) and mutualists (absorb nutrients from living hosts & benefit hosts) 33  Fungi Body Structure Reproductive structure – where haploid spores are Hyphae – produced absorption of nutrients; walls with chitin (allow for strength) Mycelium– network of hyphae 34 Hyphae: Trapping & killing prey Soil fungus Hyphae penetrate nematode and fungus digests nematode’s tissues Some hyphae can feed on live animals! Haustoria: Specialized hyphae Nutrients extracted from living plant cell 35  Fungi Bread (single-celled fungi: Beer (single-celled fungi: yeast) yeast) Rhinosporidiosis: tissue with sporangia File:Beauveria.jpg File:Penicillium notatum.jpg Biocontrol Penicillium fungus Shoyu koji mold 36 37 Reproduction 38  Euglenozoans Fungi Phylogeny Forams Diatoms Based on DNA evidence - Fungi more closely related to unicellular Domain Eukarya Ciliates Red algae nucleariids (some consider to be protists, Green algae others do not) Plants - Animals are more closely related to unicellular Tubulinids Fungi choanoflagellates (some consider to be Animals protists, others do not) Euryarcheotes What does the above indicate? Multicellularity Archaea Domain Thaumarchaeotes arose separately in fungi and animals! Crenarcheotes COMMON ANCESTOR Proteobacteria OF ALL LIFE (Mitochondria)* Domain Bacteria Chlamydias Spirochetes Gram-positive bacteria Cyanobacteria (Chloroplasts)* 39  Fungi Phylogeny 7 phyla (divisions) Estimated 1.5 million species 100K formally classified Mycete means fungus  Select fungal groups 1. Cryptomycetes & microsporidians = sister group/ basal fungal lineage 2. Zoopagomycetes = produce asexually & behavioral changes in the insects they parasitize 3. Ascomycetes = sac fungi, named for the saclike asci 4. Basidiomycetes = mushrooms, puffballs, and shelf fungi 41 Basidiomycetes Chytrid fungi Implicated in global amphibian declines 43 Chytrid fungi Implicated in global amphibian declines mycosis 44  Amazing Fungi File:Armillaria ostoyae.jpg Fairy Ring: mycelium grows 30 cm/year Reproductive structures can appear in a few hours Honey Fungus (Armillaria ostoyae) 2,200 acres (2,424 football fields) 2,400 years old 45  Fungi Are Important Symbionts Mycorrhizae are plant symbionts that aid in nutrient acquisition Many modern agricultural practices (fungicide treatments) disrupt mycorrhizae Leads to relying on fertilizers Excess fertilizers harm the environment (impact other organisms, pollute water resources) 46 Fungi Are Important Symbionts 47  Fungus-Animal Symbiosis The ants and fungi have evolved together. In most cases, they need the other in order to survive. Think about how some insecticides and fungicides that humans use to control “pests” could impact this relationship between the ants and fungi. Leaf-Cutter Ants Farm fungi. Ants feed on the fungi, and the fungi break down the leaves for the ants. (Aids in digestion and detoxification – remember, plants can have strong chemical defenses!)48 Lichens Symbiosis between photosynthetic organism and fungus Break down surfaces (chemically and physically) Some lichens are nitrogen-fixers (add nitrogen to ecosystems) 49  Plants and Fungi Key points from today’s lecture 1) Fungi are not plants. Fungi are heterotrophs that feed by absorption; they lack chlorophyll. 2) Fungi have radiated into a diverse set of lineages. They play key roles in nutrient cycling, ecological interactions, and human welfare. Mycorrhizal fungi form mutualistic symbioses with many plants. 3) Land plants evolved from green algae. Challenges of a terrestrial environment include gravity, environmental fluctuation, and water availability. Early benefits include reduced competition, herbivory, and parasitism. 4) Seeds and pollen of gymnosperms and angiosperms are key adaptations for life on land. 5) Key adaptations of angiosperms include flowers, fruits, and double fertilization. Flowering plants reproduce sexually, asexually, or both. Many species have mechanisms to avoid self-fertilization. 6) Angiosperms form many symbiotic relationships with animals to provide pollination, seed dispersal, and maintenance.  Next: Diversity of Life – Animals Before the Next Class ▪ Read Ch. 32, Ch. 33, Ch. 34 51