(Bacteria and Archaea) + (Protists and Fungi)

All life has what? (prokaryotes and eukaryotes)

DNA, RNA, cell membrane, ribosomes, and ATP

Three domains of life

Bacteria, archaea, and eukaryotes

Bacteria vs. archaea

Different proteins in their cell walls, different cell membrane components, different cellular machinery (for transcription and translation), no known pathogens (cause disease in host) for archaea

What tells us that Eukaryotes are more closely related to Achaeans

Genetic similarity, similar cellular machinery (for transcription and translation), archaea use histones, many other traits

Human microbiome

Community of microbes that live in or on the human body (bacteria, archaea, fungi, viruses, etc.). About 38 trillion bacterial cells and few archaea comparatively.

Types of bacteria

Cocci (circle shaped), Bacilli (rod shaped), and others (many different shapes)

Methanogens

Important decomposers and archaea. Uses H2 to reduce CO2 to methane but are anaerobic so O2 kills them.

Halophile

Archaea. Thrive in water 10x as salty as the ocean.

Thermophiles

Archaea. Live in up to 105 degrees Celsius

Acidophiles

Archaea. Live in places w/ a pH below 1.0

How do bacteria reproduce

Binary fission. Similar to mitosis but not the same as the nucleus doesn’t get split in the way it does in mitosis.

Lateral Gene Transfer

exchange of DNA across species. Shows how phylogenies aren’t completely linear.

Differences between bacteria, archaea, and eukarya

Prokaryotes (bacteria and archaea) and Eukaryotes (eukarya)

endosymbiosis

It starts with two independent bacteria and ends with one bacteria engulfing the other and each providing for each other. Then, it is passed down.

How does the endosymbiosis theory explain arising of mitochondria/chloroplast

Cyanobacteria (chloroplast) and proteobacteria/an aerobic bacteria (mitochondria) was involved and engulfed by a prokaryote which made the ancestral eukaryote

Why was the mitochondria so important

Powerhouse of the cell, allowed aerobic respiration, and allowed the evolution of multicellular life during the period of increasing atmospheric O2

Simple Multicellular Organisms

Adhesion molecules present (stick + stay together), most/all cells retain a full range of functions (including reproduction), every cell is in contact w/ external environment

Complex Multicellular Organisms

Cell communication, different types of tissues and organs, signaling/sensory systems, regulatory genes to map a 3-D body

Why isn’t bigger always better for a single celled organism

The surface area of which nutrients and gasses can be absorbed is much smaller than the volume of the cell where resources are used so cell demands too much resources

What is the solution instead of becoming a bigger single cell organism

Have multiple small cells to increase surface area but also manage volume

Pros of multicellular

• Cells can specialize and do different things

• Larger so lower risk of being eaten

• Can access more of environment if moving

• Longer lifespan

• Sometimes complexity means greater effiency/adaptation

Pros of unicellular

• Needs less energy than multicellular

• Reproduction is easier and faster

• One cell so doesn’t need to cooperate with many cells

• It doesn’t need much energy to grow

Prokaryotes and Eukaryotes similarity

DNA, cell wall (some for eukaryotes), cell membrane, and alive

What do eukaryotes have that prokaryotes don’t

Nucleus, meiosis, organelles, mitochondria, chloroplast(some), multicellular(some)

When did fungi, animals, plants, and protists split

Diverged around 1.5 billion years ago

Heterotroph

can’t make their own food so they consume other organisms

autotroph

can make their own food

Fungi

Heterotroph that absorbs food. Within cell walls made of chitin. Eukaryotes.

Animals

Heterotrophs that ingest food. Has no cell walls. Eukaryotes

Plants

Photosynthetic autotrophs with cell walls made of cellulose. Eukaryotes

Protists

Not one of the 3 other eukaryote groups. Is a catch-all category for things that are mostly unicellular but not closely related. A polyphyletic group.

Protists life cycle

Can be diploid or alternation (from haploid to diploid or vice versa), but commonly haploid

How do protists get food?

Some eat organic matter while others get photosynthesis through the secondary endosymbiosis which helped them acquire the ability

Beneficial protists

Protists can give things such as food through their processes like photosynthesis which can help environments. Critical builders of marine ecosystems

Harmful protists

When in a favorable condition, can reproduce enormously. Toxins produced by them can kill or harm vertebrates (ex: fish and humans)

Plants, Fungi, and Animals all likely had a protist ancestor. Which of the three are closely related?

Fungi and Animals

Fungi Range

Shows how they can be extremely small and extremely big. Also shows how they can be good to consume or extremely deadly.

Fungal nutrition

Fungi absorb food (organic material) by secreting digestive enzymes and absorbing food through cells

Yeast

Can refer to many different species. Not monophyletic group. Single celled growth. Fungi.

Hyphae

Multi-cellular branching growth

Decomposers

Feed on dead material. Can break down lignin in wood. Fungi.

Pathogens

Microorganisms/agents that can cause disease. Fungi

Close relationships fungi have

• Mycorrhizae: exchange nutrients for sugar w/ plants

• Lichens: symbiotic association between fungus and algae (important for soil formation)

What makes the fungi life cycle so unique?

Involve both asexual and sexual cycles. Sometimes, sexual stage can look very different from asexual stage.