Chapter 25: History of Life Flashcards
1
Q
Chp 25
Macroevolution?
A
- broad pattern of evolution above species level
- fossil records show macroevolutionary changes: emergence of terrestrial vertebrates, impact of mass extinctions, etc..
2
Q
Chp 25
How did chemical & physical processes on early Earth produce very simple cells?
A
- abiotic synthesis of small organic molecules
- joining of small molecules into macromolecules
- packaging of molecules into protocells
- origin of slef-replicating molecules
3
Q
Chp 25
Synthesis of organic compounds on early earth
A
- Hydrothermal vents: area on the seafloor where hot eater & minerals gush into the ocean; a place where organic compounds could have been produced
- Alkaline vents: release water with high pH and warm water; more suitable for formation of stable organic compounds
- Meterotes; another possible source of organic molecules
4
Q
Chp 25
Abiotic synthesis of macromolecules
A
- Small organic molecules can polymerize when they are concentrade on hot sand/clay/rock
- ex: adding montmorillonite (soft mineral clay) greatly increase rate of vesicle formaiton (whcih cause simple growth, metabolism, etc…)
5
Q
Chp 25
Self-replicating RNA
A
- rna plays a huge role in protein synthesis
- rna molecules, ribosomes, can catalyze many different reactions
- natural selection and coppying errors have contributed to rna being able to self replicate
6
Q
Chp 25
Fossil records document history of life
A
- sedimentary rocks: layers called strata are the richest source of fossils
- fossil records are biased based on species existing for a long time, abundancy, and having hard parts (shells & skeletons)
- radiometric dating: relative ages of fossils can be inferred
- a radioactive parent isotope decays to a daughter isotope
- half life: time required for half the parent isotope to decay
- longer half lives help date older fossils
7
Q
Chp 25
The origin of new group of organisms
A
- mammals belong to tetrapods
- unique mammalian features can be traced in the fossil record
8
Q
Chp 25
What is the geologic record devided into?
A
- Hadean, Archaean, Proterozoic, & Phanoerozoic eons
- phanoerozoic is dvided into: paleozoic, mesozoic, & cenozoic
- Hadean: origin of solar system & earth
- Archaean: prokaryotes develop
- Proterozoic: atmospheric oxygen, single & multicellular eukaryotes
- Phanoerozoic: animals, colonizations of land, humans, present
9
Q
Chp 25
1st single celled organism
A
stromatolites: oldest nown fossils
10
Q
Chp 25
Photosynthesis & the oxygen revolution
A
- oxygen was produced by oxygenic photosynthesis
- oxygen revolution caused the extinction of many prokaryotic groups
- some groups adapted and others using cellular respiration to harvest energy
11
Q
Chp 25
1st eukaryotes
A
- endosymbiosis: when a prokaryotic cell engulfed a small cell that would evolve into mitochondrion; how eukaryotes originated
- endosymbiont: a cell that lives within a host cell
- serial endosymbiosis: says that mitochondria evolved before plastids (chloroplasts & relevant organelles) through a sequence of endosymbiotic events
12
Q
Chp 25
Origin of multicellularity
A
- evolution of eukaryotic cells -> greater range of unicellular forms
- second wave of diversification: algae, plants, fungi, and animals develop
13
Q
Chp 25
Cambiran explosion
A
- refers to sudden appearance of fossils resembling modern animal phyla in cambrian period
- provides first evidence of predator-prey interactions
- new defense adaptaions appeared
14
Q
Chp 25
Plate tectonics
A
- theory that says that earth’s crust is composed of plates floating on earth’s mantle
- continental drift: movements in mantle that cause plates to move over time
- these plates moving can collide to form mountains or cause eartthquakes
15
Q
Chp 25
Consequences of continental drift
A
- Pangea formation effect were: deepening of ocean basins, reduction in shallow-water habitat, colder/drier climate inland
- contiental drift caused organisms to adapt as climate changes occured
