Biology 1114 Final - Chiucchi
Plant phylogeny
(left to right) nonvascular plants, vascular seedless plants, gymnosperm, angiosperm
Parts of flower
- 4 whorls - 2 are sterile (sepal and petal) - 2 are fertile (stamen & carpel)
Glomeromycetes
- 90% of plants have these on roots - Mycorrhizae: mutualistic with plants, helps plant absorb nutrients and fungus gets carbohydrates from plant
Key characteristics of fungi
- Absorptive heterotrophs: digestive enzymes secreted into surroundings, fungus then absorbs digested products - Most are decomposers, some are parasitic or symbiotic - Body is a network of thin filaments (hyphae)
Mollusca
- Bilateral symmetry, triploblastic - Protostome: lophotrochozoans - Gastropoda: snails, conch - Bivalvia: clams, oysters, scallops - Cephalopoda: squids, octopus
Chordata
- Bilateral symmetry, triploblastic - Deuterostome - Tunicates, vertebrates
Echinodermata
- Bilateral symmetry, triploblastic - Deuterostomes - Sea urchins, starfish, sand dollar
Platyhelminthes
- Bilateral symmetry, triploblastic - Protostome: lophotrochozoans - Flatworms (tapeworms, flukes)
Nematoda
- Bilateral, triploblastic - Protostome: ecdysozoa (cuticle) - Molts as it grows - Roundworms - Tardigrada: "water bears"
What did early life look like?
- Consisted of prokaryotes (at least 3.6 billion years old) - Fossil stromatolites - Early photosynthetic prokaryotes produced oxygen atmosphere
HOX Genes: What kind of responses do they generate in organisms?
- Example: telling cells of a fly where to start building wings - Can lead to homeotic mutations which cause loss-of-function or gain-of-function - Loss-of-function ex: development of second leg pair into antennae - Gain-of-function ex: results in legs where antenna should be (antennapedia)
Key characteristics of protists
- Extremely diverse - Only share one characteristic: eukaryotic - Do not belong in any other kingdom - Range from unicellular to multicellular (algae)
Seedless vascular plants
- First to evolve xylem & phoelem - Use spores for reproduction (wind dispersal)
Different fields of ecology?
- Individual - Population - Community - Ecosystem (biotic and abiotic)
What is coevolution?
- Interactions between species are strong - Selection and evolution across species boundaries - Selection is driven by the interaction between species
Why did the Cambrian happen?
- Intrinsic explanation: something in animals changed, like HOX and HOX-like genes were duplicated in bilaterians - Extrinsic explanation: ancient atmosphere had insufficient O2 to allow evolution of active lifestyles
HOX Genes: Why are they important?
- Makes proteins that signal, activate, mark or otherwise communicate with other genes and their products - Crucial for body plan/development (sets up anterior-posterior and dorsal-ventral axis)
Ascomycetes
- Morels, truffles, bread molds, yeast - Economically important: yeast, bread, wine, beer - Gastronomically important: edible mushrooms like morels, truffles, cheese molds - Medically important: source for penicillin
Arthropoda
- Most diverse - Bilateral symmetry, triploblastic - Protostome: ecdysozoa - Insects, Milli/Centipedes, arachnids, crustaceans
Why do we see coevolution occur?
- Mutualism - Escalating "arms race" between predator and prey - Co-speciation (host/parasite interaction)
What happened in the Hadean?
- No fossil record - Differentiation of Earth into crust, mantle, and core - Origin of atmosphere via volcanic outgassing (little O2) - Condensation of water to form freshwater lakes, streams, etc - Origin of continental crust
Porifera
- No tissues, no symmetry - Sponges
Nonvascular plants
- No vascular tissue or roots - Simplest & most primitive - Dependent on water for reproduction - Small - Water and nutrients move by diffusion - Mosses
What happened in the Archaen?
- Origin of life - Early organisms had methane, SO4, H2S, and produced CO2 and alcohol as byproduct - Photosynthetic organisms appear - Atmosphere converted to oxygen environment
Types of symbiosis
- Parasitism - Mutualism - Commensalism - Predator-prey -Competition
Gymnosperm
- Produces seeds - Uses seeds for dispersal - "naked seeds" - Conifers - Don't need water to reproduce - Don't produce flowers or fruit
Cnidaria
- Radial symmetry, diploblastic - Cnidocytes: stinging cells - Jellyfish, coral, sea anemones
Lichen
- Relationship between fungus and photosynthesizer - Important in making soil - Can live in extreme conditions - Provides protected environment and minerals for autotrophs while autotrophs supply carbohydrates
What happened in Cambrian?
- Relatively sudden appearance of diverse animal forms in fossil record - All "major" phyla were present by the end
Zygomycetes
- Rots produce, grows fast - Ruins food
Annelida
- Segmented - Bilateral symmetry, triploblastic - Protostome: lophotrochozoans - Polychaeta, Oligochaeta (earthworms), Hirudinea (leeches)
Gene Families: How does natural selection operate through the formation of gene families?
- Selection acts independently on each gene - Evo-devo looks at ARRIVAL of the fittest
Predator-Prey
- Warning colors - Cryptic coloring "camouflage" - Mimicry Batesian: "sheep in wolf's clothing"; the mimic isn't poisonous or dangerous Mullerian: two or more species have warning coloration that is similar
Chytrids
- Water and soil - Produce swimming pores - Fungicide used in lakes, killing frogs - Parasitic
Key characteristics of land plants
1. Apical meristems (causes root/shoot to grow and increase in length) 2. Alternation of generations 3. Tough, resistant spores from sporangia 4. Special organs for production of gametes
5 phyla of fungi
1. Chytrids 2. Zygomycetes 3. Glomeromycetes 4. Ascomycetes 5. Basidiomycetes
Four key distinctions that divide the animals
1. True tissues (Eumetazoa) vs None (Parazoa) 2. Radiata vs Bilateria (Symmetry) 3. Blastopore Fate (deuterostome vs protostome) 4. Protostome Development (lophotrochozoa vs ecdysozoa)
Alternation of generations
1. sporophyte produces haploid spores by meiosis 2. Spores germinate and divide by mitosis and develop into multicellular, haploid gametophytes 3. Gametophytes produce unicellular haploid gametes by mitosis 4. 2 gametes unite during fertilization to form a diploid zygote 5. Zygote divides by mitosis and develops into multicellular, diploid sporophyte
Mutualism
Beneficial to both species involved
Gene Families: How do they come about?
Clusters of genes similar in structure and sequence
How can we test for coevolution?
Compare fitness of the species with/during the relationship and fitness of the species without the relationship
Panspermia
Earth is constantly bombarded with material from interstellar space consisting of organic compounds which may have provided building blocks of life (ex: Murchison meteorite had amino acids)
Key features of prokaryotes/eukaryotes
Eukaryotes have a DNA containing nucleus and can be single-celled or multicellular while prokaryotes (bacteria and archaea) do not have a nucleus and are unicellular
Gene Families: Gene duplication role
Gene duplications are the most important source of new genes
HOX Genes: What are they?
Genes that control where, when, and how other genes are expressed.
Ploidy levels of different cell types
Haploid: 1 copy of each chromosomes, gametes Diploid: 2 copies of each chromosome, somatic cells, plant cells
Competition
Individuals fight for the same resources lowering fitness of both parties
Abiogenesis
Life originated from abiotic precursors already existing on Earth
Commensalism
One species benefits and the other is neither benefitted nor harmed
Parasitism
One species benefits but the other is harmed
What do flowers do for the plants?
Reproduction: have reproductive structures that attract pollinators and develop fruit
What is needed for coevolution to happen?
Succession: gradual change in species composition over time Primary: no soil exists Secondary: community has been damaged but soil remains
Miller-Urey Experiment
Synthesized organic compounds from inorganic precursors (water, methane, ammonia, hydrogen) and produced 20+ amino acids and proved evidence for abiogenesis
What is ecology?
The study of interactions of organisms with their environment
Angiosperm: why are they so diverse?
Utilize methods to attract pollinators and prevent selfing
How does a fungus live (mostly)?
Warm, moist, dead matter - Feeds off of dead matter
To be coevolution, the relationship must be the ____ ____ ____ and there must be _____ in the response
primary selective force; reciprocity
Basidiomycetes
toadstools