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