Midterm 2

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homology

Similarity in traits between different species due to a shared common ancestor.

synapomorphy

A shared, derived character or trait that distinguishes a clade from other organisms, indicating a common ancestor for that clade.

parsimony

a principle that suggests the simplest explanation for a phenomenon is likely the correct one

extremophile

a microorganism, especially an archaean, that lives in conditions of extreme temperature, acidity, alkalinity, or chemical concentration.

Alteration of Generations

Gametophyte → gamete → fusion → sporophyte → spore → gametophyte

endosymbiotic theory,

proposes that mitochondria and chloroplasts, organelles within eukaryotic cells, were once free-living prokaryotic cells that were engulfed by larger host cells and developed a symbiotic relationship

haploid

having a single set of unpaired chromosomes. (n)

diploid

containing two complete sets of chromosomes, one from each parent. (2n)

sporophyte

a diploid, multicellular spore-producing phase in the life cycle of the plant body which exhibits alternation of generations

gametophyte

the gamete-producing and usually haploid phase, producing the zygote from which the sporophyte arises. It is the dominant form in bryophytes.

meiosis

a process where a single cell divides twice to produce four cells containing half the original amount of genetic information

mitosis

the process by which a cell replicates its chromosomes and then segregates them, producing two identical nuclei in preparation for cell division

desiccation

the process of drying out or the state of being extremely dry

Phylogonies

analysis of “omics“ data resembles phylogenetic analysis or the study of evolutionary relationships among biological entities

phylogenies and why we study them?

evolutionary hypotheses, testable hypothesis (DNA classification), biodiversity (new species), economics (buying salmon), forensics (crime solving), studying pathogens, cancer

Types of phytogenetic trees

monophyletic, paraphyletic, and polyphyletic

monophyletic group

a group of organisms that share a common ancestor.

(ancestor + all descendants)

paraphyletic group

Monophyletic group that is missing a member

(ancestor + some but not all descendants.)

polyohyletic group

Two or more organisms that have a trait in common, but evolved it independently

(does not include the most recent common ancestor)

What does each branch mean?

relationships, genetic distance, extinction, and time

Information on phylogenies?

out groups, divergence, synamorphies, node(most common ancestor)

Homologous

body parts of organisms that have the same anatomical features, thus, indicating a common ancestor or developmental origin

Homoplasy

the development of organs within different species, which resemble each other and have the same functions, but DID NOT have a common ancestral origin

independently derived, not homologous

convergent evolution

the process whereby distantly related organisms independently evolve similar traits to adapt to similar necessities.

Vestigial Trait

a physical characteristic in an organism that has lost its original function through evolution

(ex, tailbone)

angiosperm (flowering plant)

a plant that has flowers and produces seeds enclosed within a carpel.

Precambrian order

Precambrian

1. Origin of life

2. Origin of photosynthesis (&O2 production)

3. Origin of eukaryotes

4. Origin of multicellular animals

• Phanerozoic Eon —> Proterozoic Eon —> Archaean Eon —> Haden Eon

Adaptive Radiation

rapid production of many decedents species from a single lineage (ex. cambrian explosion)

Mass Extinction

A large number of diverse species around the world (60% wiped out) and are caused by catastrophic events (opposite of adaptive radiation)

Background Extinction

The natural, ongoing extinction of species at a relatively low rate, occurring continuously throughout Earth's history

Bacteria and Archaea

• two of three largest branches on tree of life

• most are unicellular, ALL are PROKARYOTIC

• LACK a membrane-bound nucleus

• the two differ in the types of molecules that make up their plasma membrane and cell walls

• Antibiotics that poison bacterial ribosomes do not affect ribosomes of archaea or eukaryotes

Prokaryotes

single-celled organisms lacking a nucleus and other membrane-bound organelles

Eukaryotes

are more complex, larger, and contain a nucleus and other organelles.

Microbiome

community of microbes that naturally inhabit particular areas and encompass all the genetic material contained within in

The largest bacteria is almost as big as a fruit fly?

True

How are bacterias different from viruses?

Bacteria are living cells with their own cellular machinery, while viruses are not living and require a host cell to reproduce

How do viruses reproduce?

Must infect a host cell and use its resources to create new viral particles. This process involves several steps: attachment, penetration, uncoating, replication, assembly, and release

Microbes

are living organisms that are invisible to the naked eye, for example, bacteria, fungi, viruses, algae, archea, …etc

autotrophs

organisms that produce their own food from inorganic substances

heterotrophs

obtain energy by consuming other organisms. 

Six feeding strategies of bacreria and archaea to make ATP

Photoautotropes, Chemoorganoautotroph, chemolithoautotrophs, photoheterotraophs, Chemooganheterotrophs, Chemolithotrophic heterotrophs

Photoautotrophs

specific type of phototroph that also utilize carbon dioxide as their sole carbon source to produce organic compounds through photosynthesis.

Chemotrophs

an organism that obtains energy by the oxidation of electron donors in their environments. (uses photons OPPOSITE of photoautotropes)

• organic (chemoorganotrophs)

• inorganic (chemolithotrophs)

Chemoorganoautotroph

use organic compounds as an energy source

chemolithoautotrophs

an autotrophic microorganism that obtains energy by oxidizing inorganic compounds, or utilize inorganic compounds

Photoheterotrophs

utilize light energy

Chemoheterotrophs

get their energy from breaking down organic molecules

chemolithotrophic heterotrophs

organisms that obtain energy by oxidizing inorganic compounds (like chemolithotrophs) but require organic carbon sources for growth (like heterotrophs)

Bacterica vs Archea distinguishing factors

Gram-Positive Cell Wall

cells looks purple under microscope, and have an extensive amount (a lot) of carbohydrate peptidoglycan

Gram-Negative Cell Wall

cells look pink, and the cell wall has a thin layer containing peptidoglycan and outer phospholipid bilayer

Gram Stain

Dyeing system to examine cell walls

Koch Postulates

a set of four criteria used to establish a causal relationship between a microorganism and a disease

• Microbe present in individuals suffering from disease and absent from healthy individuals

• microbe must be isolated and grown in pure culture away from host

• if organisms from pure culture are injected into healthy experimental animal, disease symptoms appear.

• Organisms isolated from diseased experimental animal, again grown in pure culture, and demonstrated to be the same as the original organism

How do we know if a bacteria causes disease?

Kochs Postulates

1. Isolate

2. Culture

3. Give to healthy animal

4. Does it have a disease

Genetic Variation through Gene Transfer

Transformation and Transduction

Transformation (Horizontal gene transfer)

When bacteria or archaea naturally takes up DNA from the environment that has been released by cell lysis or secreted

Transduction (Horizontal gene transfer)

When viruses pick up DNA from on prokaryotic cell and transfer it to another cell

Conjunction (Horizontal Gene transfer)

When genetic information is transferred by direct cell to cell contact

Antibiotics

• Molecules that kill bacteria

• Produced naturally from soil bacteria and fungi

Biofilms

are bacterial colonies enmeshed in polysaccharied-rich matrix that shield bacteria from antibodies

Metabolic Diversity

Must acquire chemical energy that is used to make ATP, and obtain carbon compounds that can serve as building blocks for synthesis of cellular components

Light (source of energy)

Sun

Organic Molecules (source of energy)

carbohydrates, proteins, and lipids, store energy in their chemical bonds and release it during cellular respiration to fuel various cellular processes. 

Inorganic Molecules (source of energy)

Chemotrophs, can utilize inorganic molecules as a source of energy. Compounds like hydrogen sulfide, ammonia, or iron.

Aerobic respiration

O2 is the final e- acceptor

Anaerobic respiration

O2 is NOT the e- acceptor

Fermentation

No electron transport, no e- acceptor

Phototrophs

light used to excite electrons: ATP made by photophosphorylation