Bio 2- unit 4: Speciation & Unit 5: Bacteria

Speciation

a splitting event that creates two or more distinct species

Species

(Latin = kind) an evolutionarily independent population or group of populations

Microevolution

• small

  • mutations, natural selection, gene flow, genetic drift

Macroevolution

• big / divergence

  • new groups

Prezygotic isolating mechanisms

reproductive isolation before the organism is formed

Habitat

-where they live

- European blackbirds that live in different elevations and terrain, with one species favoring forests and the other grassy hills, preventing them from interacting and mating

Temporal

-time of mating

-Two species of frog in the same habitat with different breeding seasons

Behavioral

- mating rituals

-females will only mate with males of their own species, ignoring males that produce different patterns

Mechanical

-morphological (parts don't work with each other) 

-Different-shaped reproductive organs. Ducks can only be with other ducks because of the corkscrew penis

Gametic

-cytoplasmic incompatibility (wrong enzymes / different chromosomes)

-how the sperm of one species of sea urchin cannot fertilize the eggs of a different, closely related species 

Postzygotic isolating mechanisms

isolating mechanisms after the zygotic has been formed or birthed

Reduced hybrid viability

• do not survive or do not survive for very long

• the inability of chromosomes to pair correctly during meiosis: rock dove

Reduced hybrid fertility

• can’t make gametes 

• the mule, the hybrid offspring of a female horse and a male donkey

Hybrid breakdown

• offspring’s offspring do not work as well

• when a hybrid organism's subsequent generations (F2 and beyond) are sterile or have reduced fitness, preventing gene flow between parent species

  • cotton species

Criteria for identifying species

•  biological species concept

• Morphospecies Concept

•  Phylogenetic Concept

All have Advantages and disadvantages

Biological Species Concept

organisms must be able to reproduce

Reproductively isolated  “only reproduce within group” 

• Must produce viable offspring”

has to be fertile and survive (viable)

What are some disadvantages?

• asexual organisms 

• dead

Morphospecies Concept

identify different species by the morphological structure

• size 

•  height

•  physical characteristics

Morphospecies Concept advantages and disadvantages

When would we use this type of classification?

• Dino bones

• To see if things are related 

What are some disadvantages?

• When they are very similar because of the environment 

• Different environments can change

Phylogenetic Species Concepts

• Identifies species based on the evolutionary history of populations

• All organisms are related by common ancestry

Places species in a monophyletic group using a family tree

• Organisms with similar characteristics are more closely related 

• only can be used with DNA

What happens when organisms stop reproducing?

• For different species to form organisms must mating

What are populations not doing when they don’t mate?

• sharing genes
  

What does this cause the population to do?

• evolve differently from each other

Polyploidy

chromosome numbers

• Ploidy = Chromosome (genome) #

  Haploid = 1 set (genome)

  Diploid = 2 sets of genomes

How could polyploidy be an evolutionary advantage?

• reproduce with another species that can survive

• gain new traits

Examples of common polyploidies

• wheat 6n

•  Banana 2n, 3n

•  Cotton 4n

•  Tobacco 4n

• (contain more than one genome)

Fusion

 two populations merge

Reinforcement

something stops the populations from mating

Hybrid zone

form a zone of hybridization

What happens when two different populations mix?

can lead to the extinction of one

unit 5 - What are bacteria characteristics?

• Bacteria and Archaea are prokaryotic organisms

What is a prokaryotic organism?

• one cell

• do not have a neclecuis

Differences in bacterial morphology (Shape)

• Bacillus - rod

• Coccus- circle

• Spiral

• Vibrio- c shaped

Bacteria cell wall

peptidoglycan (protein-sugar) like bricks

Archaea cell walls

pseudopeptidoglycan (false& found in harsh environments), polysaccharides, glycoproteins, or just proteins

Gram Stain

• series of stains so you can see the cell walls and the differences / can see the shape

• Gram-positive: thick cell wall

  • Color- purple

• Gram-negative: thin cell wall surrounded by outer membrane (LPS)

  • Color- red

  • Resistant to-  antibiotics

    • can cause 

Capsule (bacterial accessories)

a layer of polysaccharides or proteins

allow them to stick - enhance the ability to cause disease

Endospore (bacterial accessories)

hard shell to resist harsh environments 

Bacteria can be dormant

Fimbriae (bacterial accessories)

hairs that help the bacteria stick

Flagella (bacterial accessories)

tail for swimming 
taxis - directed movement towards or away from a stimulus

Why are there so many different species of bacteria?

• 30,000 formal named species (Dykhuizen 2005) 

  • more now

Bacteria are asexual so they need to have mutations so they do not get wiped out

Conjugation

bacteria can pass genes to each other

• Bacteria have circular DNA

• Can have Smaller DNA plasmids

• Plasmids can contain antibiotic resistance genes

Heterotrophs

bacterial metabolisms? (ways of getting energy)

• energy from the environment (organic)

Hetero- different } proteins, carbs, lipids/fats, nucleic acids/DNA, RNA

Photo-Auto-trophs

bacterial metabolisms (ways of getting energy)

• Energy from the sun

Photo- light

carbon- inorganic: auto - self }make ^ themselves, take in the things to make ^: LCO2, CH4

Plants 

Chemotrophs

• bacterial metabolisms (ways of getting energy)

• energy from chemicals. (non-organic)- Us & fungi 

chemo- chemical

chemo-Hetero-Troph- gains energy/ carbon organic molecules 

energy carbon feeding

chemo-Auto-trophs

chemicals/inorganic 

Obligate aerobes

Must have oxygen

Obligate anaerobes

Oxygen is toxic

Facultative anaerobes

Can live with or without oxygen

Fermentation

no oxygen (produces alcohol)

How do bacteria help the environment?- Chemical cycling

nitrogen fixaction- turn atmospheric nitrogen into a usable form

• fixation rxn = makes molecules usable by lining organisms

How do bacteria help the environment?- Minerals become sequestered in organisms

• decomposers- organisms that break down dead organisms

How do bacteria help the environment?- cyanbacteria

• create oxygen essay

  • Why is this important to us?

• we need oxygen to live and this makes 50% of our oxygen from the ocean

What is the process that bacteria use to create oxygen? What type of metabolism would they have?

too much CO2 in the atmosphere, ocean takes it in but it is too much and kills the bacteria in the oceans turning the water into acid killing the organisms in the water

Pathogenicity

• has the ability to cause disease 

Pathogen

• an organism that can disease

Virulence factor

• gene that provides the ability to cause disease

• Exotoxins (toxin that is released all the time)

• Endotoxins (relased only when they die)

Virulence

degree of pathogenicity

Biofilms

May bacteria secrete a sticky substance

•   adhere to surfaces

resist antibiotics

Koch’s Postulates 

1. microbe must be present in a diseased host

2. isolate and grown in pure culture

3. inoculate a susceptible host (see if disease is presented)

4. reisolate microbe from symptomatic host

Robert Koch

discovered link between a particuiler bacterium and disease

How do Koch’s Postulates fit with human disease testing such as HIV?

1. Get sick organism take pathogen out. 2. isolate pathogen and grown it alone. 3. put the pathogen back into a similar organism to see if the disease is there 4. isolate the pathogen again but if you can't, it was not the thing making the disease essay

cannot do this test on people because it is unethical 

Clostridium tetani

 tetenus toxin very ten years the muscles clench and do not let go “lock jaw” the body will snap in half

endospore- toxins and a hard shell

Clostridium botulinum

• botulism attaches to muscles causes actual paralis “durrpy face”

• endospore- toxins and a hard shell

Clostridium perfringens

gangerne lossing toes

• endospore- toxins and a hard shell

halopphiles

salt loving

Many Archaean live in extreme environments

thermophiles

heat loving

Many Archaean live in extreme environments

acidophiles

acid loving

Many Archaean live in extreme environments

Biotechnology

tech to have living organism make things / products for you by changing their DNA

How can we change bacteria to benefit us?

Production of insulin

-pigs but some are algric to swine 

so we have bacteria make it for us

Bioremediation

fix using life 

• Fertilization - add other nutrients for them 

• Seeding - putting bacteria in water 

“fixing the environment using other life forms”

Protists are eukaryotic organisms

Most are single cellular

• Few multicellular- Kelp (seaweed)

• Commonly found in water

Some form a cysts- survival structure

How are protists related to us?

Protists are the ancestors to all other eukaryotes 

traits found in all other organisms

Multicellularity

Photo or heterotrophs: be able to eat and break stuff down

Reproduce both sexually and asexually

Movement by proteins: proteins that slide and move so we can move

Forms a cyst stage

endosymbiotic theory

first eukaryotic organisms begin

chloroplast and mitochondria 

bacteria that can make sugar from the sun (cyanobacteria) and bacteria that ate that bacteria 

one day it took it in and it took in things they both needed - cholorplast 

later mitochondria 

What are some of the evidence for this theory?

1. cholorplast is the same size as bacteria 

2. can reproduce like bacteria 

3. have their own DNA (circler)

How do we group protists?

Protists are grouped by movement

Pseudopods

 have the false feet

Amoeba- found in water, most harmless

eats whatever it touches 

pseu- false pod - foot 

Flagellates

move with a flagella 

some cause disease (trypansoma- chagas disease)

 kissing bug it likes bloods of dogs 

Cilliates

move with cilia (little hairs)

paramecium - harmless

Apicomplexans

can not move

some are disease-causing—Plasmodium and Toxoplasma. 

How do protists affect the environment?

Large populations- 500 - 600 per ml

Serve as primary producers

Very ecologically important- Many are photosynthetic

they cannot get enough energy to become mutlicelluar - this is the best way to do that

Sequester CO₂

What is photosynthesis and why is it important?

CO2 + H2O -> C6H12O6 + O6

ability to capture energy from sun

using carbon in the environment to use in the sugars we use to live and breath

Bloom

rapid population growth 

• Caused by – pollution (nitrogen and phosphors)

Some create light by bioluminescents

How do protists affect human health?

Dinoflagellates- produce toxins

• Paralytic shellfish poisoning

Eutrophication- massive die off due to low oxygen

Plant disease

• Phytopthera infestans*- irish potato blight 

• 430,000 deaths and mass immigration

Why is this important to use?

• planting and eating infected potatoes 

• no more food everyone came to US

Challenges in controlling malaria

• drug resistance

•   insecticide resistance 

• evolves quickly

Plasmodium spp.- cause malaria

• 435,000 deaths in 2017

• U.S. cases 1,500 case/year

• 63 local transmission 1957-2014

• Anopheles mosquito vector

What are fungi?

Fungi are eukaryotic organism 

11,000 known species

Fungi have two forms

• Yeasts- single cellular fungi

• Molds- multiellular fungi

Hypha- fungal filaments (hyphae - Plural)
Mycelium- mass of hypha