312: Diversity of Life Part A

Three main domains of life

bacteria, archaea, eukaryota

Bacteria (domain)

The dominant life form on earth for over 3.5 billion years

horizontal gene transfer

when genetic material is transferred directly from one species to another via viral infection or bacteria conjugation

Bactillati

Example of bacteria. Mostly gram-negative, commonly found in terrestrial environments, includes Cyanobacteria, which are photosynthetic and can be found almost anywhere

Archaea (domain)

Originally classified as bacteria. Paraphyletic since one lineage of archaea are eukaryotes

nanoarchaea

example of archaea. They do a lot of horizontal gene transfer in other domains. Really small!

Asgard

includes the eukaryotes

Eukaryota

Complex cells with nuclei and organelles

protista

mostly unicellular, autotrophic + heterotrophic. Junk kingdom and polyphyletic nonsense

amoeba

protists with pseudopod extensions used to move, but they are more like a cell type than a distinct lineage

plants

multicellular green plants. Autotrophic through photosynthesis. Have a cell wall

animals

multicellular, heterotrophic, no cell walls, mobile in at least one developmental life stage

fungi

multicellular. Heterotrophic. Decomposers

charophytes (simple algae)

Evolved during the Cambrian period and gave rise to the first land plants

Embryophytes (land plants)

plants evaded land during the Ordovician period

bryophytes (mosses, liverworts, hornworts)

non-vascular land plants, live in moist habitats

Tracheophytes (vascular plants)

vascular plants evolved in the Silurian period

Lycophytes (Clubmosses)

Not true mosses. Ancient tree-like clubmosses covered the lands during the Carboniferous period

Monilophytes (Ferns, horsetails, whisk ferns)

reproduce with spores, largest group of ferns, diversified during the Cretaceous, alongside flowering plants

Spermatophytes (seed plants)

seed plants evolved during the Devonian period

seed dispersal methods

Wind, animal transport, water, explosive propulsion, and human cultivation

gymnosperms (woody, perennial seed plants)

Reproduce with male/female cones

Conifers

gymnosperm example. Include pines like the Bristlecone

Angiosperms (flowering plants)

appeared during the Cretaceous and are older than many extant mammals like primates.

• males: pollen from anthers

• Females: eggs from ovaries. Fertilized ovaries develop into fruits that cover the seed

What is a fruit?

fleshy covering of seeds that developed from the ovaries of flowers

Early flowering plants

Diverged In the last Cretaceous

• magnolias

monocots

evolved from angiosperms, include orchids, bananas, and grasses

orchids

Half of all monocot species are orchids. Found on every continent, even north of the arctic circle

Co-evolution

orchids and their insect pollinators seemed to evolve in tandem, each influencing the other’s evolution, resulting in ever-elaborate relationships

grasses

monocots. Include all cereals: oat, corn, quinoa, wheat, rice, maize, barley, etc..

eudicots

the most diverse group of plants in history

Early eudicots

ex: cacti

eduicots: rosids

ex: roses

Brassica

cabbage, kale, broccoli, etc.. evolved from one species of brassica

eudicots: asterids

coffees, forget-me-nots, sunflowers

Fungi

Five main phyla

Chytridiomycota

simplest “true” fungi. Appeared during the late pre-Cambrian over 500 MYA. Only fungi to retain flagella. Mostly aquatic and act as parasites on amphibians

Zygomycota

decomposers. “Mold” that propagate quickly on old bread, fruits, and vegetables

ascomycota

characterized by sacs that carry spores. Includes bakers and brewer’s yeast

basidiomycota

characterized by visible fruiting reproductive bodies called basidia in the “mushroom”

glomeromycota

all members of this phyla produce mycorrhizae, which are mutualities growths on the roots of plants

animals (aka metazoa)

Multicellular, eukaryotic organisms that develop of a blastula, consume organic material, consume oxygen, are animate (they move), and can reproduce sexually