Module 1 Overview (Biodiversity) Flashcards
How old is Earth?
4.6 billion years old
ORDER the EONS that describe the HISTORY OF EARTH from OLDEST to MOST RECENT
Hadean (4.6 - 4.0 BYA) - BEFORE LIFE
Archaean (4.0 - 2.5 BYA) - EARLY LIFE
Proterozoic (2.5 - 542 MYA) - OXYGEN ACCUMULATION & FLOURISHING OF EARLY LIFE
Phanerozoic (542 MYA - present!) PROLIFERATION OF PLANT AND ANIMAL LIFE
How is the HISTORY OF EARTH arranged in terms of GREATEST TIME SCALE to SMALLEST SCALE
Eons, Eras, Period, MYA
What the THREE PRIMARY DOMAINS OF LIFE?
Eukarya, Bacteria, Archaea
How do EUKARYA differ from both BACTERIA AND ARCHAEA in a PHYSICAL SENSE?
BACTERIA AND ARCHAEA are SINGLE CELLED MICROORGANISMS WITH NO NUCLEI (PROKARYOTES) and ALL HAVE CELL WALLS
EUKARYA are different in that they have NUCLEI THAT ARE MEMBRANE BOUND FROM THE REST OF THE CELL (EUKARYOTES) and NOT ALL HAVE CELL WALLS
How do ARCHAEA AND BACTERIA REPRODUCE? EUKARYA?
Generally through BINARY FISSION (creates EXACT REPLICAS of the PARENT GENERATION UNLESS MUTATIONS***)
EUKARYA reproduce and differentiate through MITOSIS AND MEIOSIS (results in a mix of GENETIC MATERIAL - GAMETES HAPLOID)
T/F: ARCHAEA are MORE CLOSELY RELATED to BACTERIA than EUKARYA
FALSE!
ARCHAEA are more CLOSELY RELATED to EUKARYA when considering the PHYLOGENETIC TREE despite how similar they seem to BACTERIA.
WHY can PROKARYOTES occupy a BROAD SET OF ENVIRONMENTS?
Primary reason? Their DIVERSE METABOLIC CAPACITY AND PROCESSES!
PHOTOTROPHS - OBTAIN ENERGY FROM SUNLIGHT
CHEMOTROPHS - OBTAIN ENERGY FROM CHEMICAL COMPOUNDS
ALSO, they have DIFFERENT SOURCES OF CARBON
AUTOTROPHS - CAN FIX THEIR OWN CARBON
HETERTROPHS - CANNOT FIX THEIR OWN CARBON
these diversifications lead to a host of important differences that allow for PROKARYOTES to live in such a BROAD RANGE OF ENVIRONMENTS!
(https://bpb-us-w2.wpmucdn.com/sites.gatech.edu/dist/6/1810/files/2018/12/metabolic-classification-of-organisms.png)
T/F: BACTERIAL PLASMIDS have no INTRONS
TRUE!
The GENETIC SEQUENCES in EUKARYOTES carry INTRONS!
What is the BACTERIAL CELL WALL made from?
PEPTIDOGLYCAN (a STRONG POLYSACCHARIDE that can form MANY LINKAGES to STRENGTHEN ITSELF)
T/F: BACTERIA have ONE MORPHOLOGICAL STATE
FALSE!
Bacteria have DIFFERENT MORPHOLOGIES, including a COCCUS, BACILLUS, TETRAD, etc!
How do we CLASSIFY BACTERIA?
MORPHOLOGY and GRAM STAIN (GRAM NEGATIVE OR GRAM POSITIVE)
DESCRIBE the DIFFERENCE between GRAM POSITIVE and GRAM NEGATIVE
GRAM NEGATIVE stain LESS BRIGHTLY since they have a OUTER MEMBRANE COVERING CELL WALL (harder to pierce the PEPTIDOGLYCAN)
GRAM POSITIVE stain MORE BRIGHTLY - have NO MEMBRANE covering the CELL WALL
(easier to reach PEPTIDOGLYCAN)
What are THREE DIFFERENT WAYS by which BACTERIA can share GENETIC INFORMATION?
TRANSFORMATION —-> picking up something loose from the enviornment
TRANSDUCTION —–> virus infects one and the other CONJUGATION —–> pilus attatch and share information
What is QUORUM SENSING?
HOW BACTERIA COMMUNICATE WITH ONE ANOTHER!
This is HOW IT WORKS:
Bacteria RELEASE GENE REGULATORS known as AUTOINDUCERS, and they are RESPONDERS to fluctuations in CELL-POPULATION DENSITY
What FEATURES make ARCHAEA UNIQUE from the OTHER TWO DOMAINS OF LIFE?
CELL WALL DOES NOT CONTAIN PETIDOGLYCAN!
MEMBRANES ARE:
ETHER-LINKED INSTEAD OF ESTER-LINKED
BRANCHED HYDROCARBONS/ISOPRENOID CHAINS INSTEAD OF FATTY ACID CHAINS
MONOLAYERS AT TIMES INSTEAD OF BILAYERS
T/F OXYGEN ACCUMULATED QUICKLY DURING THE OXYGEN REVOLUTION
FALSE!
Evidence shows that the OCEANS weren’t fully OXYGENATED until 850 MYA and the SLOW ACCUMULATION OF OXYGEN can also be seen through the BANDED IRON FORMATIONS IN SEDIMENTARY ROCKS when free oxygen reacted with iron to form IRON OXIDE
During what EON did THE OXYGEN REVOLUTION/CATASTROPHE OCCUR?
Proterozoic
During what EON did THE CAMBRIAN EXPLOSION OCCUR?
Phanerozoic
What are TWO EXTREMELY IMPORTANT WAYS that PROKARYOTES impact HUMAN HEALTH?
Biological nitrogen fixation (BNF) and bioremediation
DESCRIBE the nature of the ENDOSYMBIOSIS THEORY
The ENDOSYMBIOSIS THEORY says that EUKARYOTES AROSE from an ARCHAEA ENGLUFING AN ANCIENT BACTERIAL CELL —> MUTUALISTIC RELATIONSHIP —> can tell that this occured because of the PRESENCE OF MITOCHONDRIA AND CHLOROPLASTS (in plant cells) and CELLS CAN’T REFORM THESE (come from REPRODUCTION) and they ALSO HAVE THEIR OWN DNA!
T/F The ENGULFMENT of a CYANOBACTERIA-LIKE ORGANISM has occured TWICE in the HISTORY OF PROKARYOTES
TRUE!
1) Englufment of cyanobacteria by Archaeplastida (MOST EVIDENT IN SPECIES)
2) Engulfment of cyanobacteria by Paulinella
What are some FORMS OF EVIDENCE for the ENDOSYMBIOSIS THEORY?
1) MITOCHONDRIA AND CHLOROPLASTS are CLOSE in SIZE to NORMAL PROKARYOTES
2) They have their OWN DNA (CIRCULAR CHROMOSOME that LACKS HISTONES)
3) Reproduce by BINARY FISSION, CELL CANNOT REPRODUCE ON THEIR OWN THROUGH OTHER MEANS (need TEMPLATE)
4) MEMBRANE COMPOSITION IS LIKE THAT OF PROKARYOTES
WHICH of the TWO (MITOCHONDRIA ENDOSYMBIOSIS and CHLOROPLASTS ENDOSYMBIOSIS) occured FIRST?
MITOCHONDRIAL ENDOSYMBIOSIS OCCURED FIRST because of the PRINCIPLE OF PARSIMONY (CHLOROPLASTS are not shared by all eukaryotes, only PHOTOSYNTHETIC ALGAE AND PLANTS)
WHAT are some FEATURES UNIQUE TO EUKARYOTES?
1) Cells with NUCLEI surrounded by a NUCLEAR ENVELOPE with NUCLEAR PORES
2) Presence of MITOCHONDRIA & CYTOSKELETON
3) LINEAR CHROMOSOMES (not CIRCULAR!)
4) MITOSIS AND MEIOSIS (some exceptions that don’t perform MEIOSIS)
T/F FOR EUKARYOTES, A SEXUAL LIFE CYCLE ALWAYS includes TWO CHANGES IN PLOIDY
TRUE!
MEIOSIS —> 2n to 1n
FERTILIZATION —-> 1n to 2n
WHAT are the THREE SEXUAL LIFE CYCLES UNDERPINNED by CHANGES IN PLOIDY
HAPLONTIC, DIPLONTIC, & HAPLODIPLONTIC (ALTERNATION OF GENERATIONS)
Describe the HAPLONTIC LIFE CYCLE
The HAPLOID STAGE is MULTICELLULAR and the DIPLOID STAGE is a SINGLE cell (FERTILIZED EGG) —> MEIOSIS occurs in the EGG immediately after FERTILIZATION —-> HAPLOID SPORES FORM —-> SPORES BECOME HAPLOID MULTICELLULAR ORGANISMS BY MITOSIS
Describe the DIPLONTIC LIFE CYCLE
The DIPLOID STAGE is MULTICELLULAR AND PRODUCES HAPLOID GAMETES —-> HAPLOID GAMETES produced by MEIOSIS over MITOSIS —> SPORES are NOT PRODUCED
Describe the ALTERNATION OF GENERATIONS
have BOTH a MULTICELLULAR DIPLOID AND HAPLOID STAGE —> DIPLOID MULTICELLULAR ORGANISMS CALLED “SPORAPHYTES” AND HAPLOID GAMETOPHYTES PRODUCE HAPLOID GAMETES BY MITOSIS CALLED “GAMETOPHYTES
What are some ROLES protists play?
Decomposers, human pathogens/parasites, photosynthesis, plant pathogens/parasites
WHERE on a PHYLOGENETIC TREE would you find LAND PLANTS?
You would most probably find them lumped together with other EUKARYOTES, but on its own clade seperate from ANIMALS and FUNGI
–> WHY? The PRESENCE OF CHLOROPLASTS IS SPECIAL TO THESE EUKARYOTIC CELLS!
WHAT is the SUPPOSED ANCESTOR of LAND PLANTS?
An AQUATIC, green, ALGAE-LIKE species
WHAT are some ADVANTAGES to living on WATER over LAND for PLANT SPECIES?
1) Plants can ABSORB WATER without the use of a SPECIALIZED TISSUE/ORGAN SYSTEM and without the worry of DESSICATION
2) WATER provides a special type of BUOYANCY, provides STRUCTURAL SUPPORT not found on land
3) SPERM AND EGG can find each other EASILY IN WATER and don’t need PROTECTION FROM DESSICATION (unlike on land)
4) WATER filters out a good bit of UV LIGHT (DESTRUCTIVE TO DNA)