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Biology > Life on Earth > Flashcards

Life on Earth Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

all living things:

A

respire, reproduce, respond, excrete waste, move

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2
Q

first living thing on earth

A

LUCA:

  • last
  • universal
  • common
  • ancestor
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3
Q

evidence of early earth:

A
  • lacked nitrogen, oxygen and carbon dioxide

- abundance of methane, ammonia, water vapour, and hydrogen gas

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4
Q

theory: outer space

A
  • rocks from meteorites, comets, and Mars have been studied, 74 amino acids found on a meteorite
  • 75% of molecules tested from space are organic
  • evidence supports theories that organic molecules evolving on primitive earth was aided by molecules from comets and meteorites
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5
Q

theory: Haldane and Oparin

A
  • believed life have evolved from conditions of early earth
  • found the basic chemical building blocks of life: amino acids chemically evolved from lightning, heat (volcanoes) and ultra violet light
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6
Q

chemical origins of light beyond earth

A
  • suggested that comets, interplanetary dust particles and meteors brought gases and water into earth’s atmosphere
  • comets made of ice and dust, as it passes through warm solar system, boiled away and gases and dust attracted to atmosphere by gravity
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7
Q

panspermia:

A
  • where life is distributed by comets/asteroids to planets
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8
Q

Urey and Miller:

A
  • experiment to test Haldane and Oparin theory: how did the origin of life on earth begin, from its own organic chemicals on earth
  • in 1953, Stanley Miller in Harold Urey’s lab sent electrical currents through a chamber of methane, ammonia, hydrogen and water
  • imitated the primitive earth conditions
  • able to yield organic compounds including amino acids: building blocks of life
  • demonstrated that complex organic molecules could be produced naturally
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9
Q

Technological advancements:

A
  • radiometric dating
  • electron microscope
  • biochemical analysis and DNA technology
  • deep ocean technology
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10
Q

radiometric dating:

A
  • different number of neutrons: called ‘isotopes’
  • some isotopes can be radioactive
  • allowed accurate dating of sedimentary rocks and fossils
  • they decay at a predictable rate: level of radiation dies down over time
  • measuring the radiation now and its ‘half-life’, work at approx. age
  • can predict entire history of life with good accuracy
  • eg. Carbon 14 > 40 000 years
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11
Q

electron microscope:

A
  • able to study fossil cells in rock, make comparisons to ‘primitive cells’ which live today
  • eg. archaea bacteria, very tolerant species
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12
Q

biochemical analysis and DNA technology:

A
  • can identify remains
  • find ‘relatedness’ of different organisms, estimate when the species divided
  • eg. chimpanzees and humans diverged only 5 million years ago
  • show all life forms are related, support evolution
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13
Q

deep sea observation:

A
  • advanced technology
  • observed hypothermal vents in 1979
  • provide optimum heat allowing organic chemistry to occur
  • spews out large volumes of nutrient and chemicals, which bacteria use in process of chemosynthesis in harsh environments
  • instead of photosynthesis
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14
Q

name the 7 major stages of evolution of living things:

A
  • organic molecules
  • membrane formation
  • heterotrophic prokaryotes
  • autotrophic prokaryotes
  • eukaryotes
  • colonial organisms
  • multicellular organisms
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15
Q

7 major stages of evolution of living things: organic molecules

A
  • 4.5 billion years ago
  • formation of organic molecules from inorganic
  • amino acids formed proteins, nucleotides etc.
  • evidence: Urey-Miller experiment, alternately panspermia
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16
Q

7 major stages of evolution of living things: membrane formation

A
  • 4 - 3.5 billion years ago
  • molecules were indistinguishable soup of gases, molecules
  • needed separate metabolic reactions so valuable metabolites can be used by itself
  • once formed, able to form cells and natural selection was possible
  • evidence: all cells are lipid based membranes
17
Q

7 major stages of evolution of living things: heterotrophic prokaryotes

A
  • 3.5 - 2.5 billion years ago
  • simplest unicellular organisms
  • no organelles
  • bacteria are most heterotrophic
  • use energy from surroundings to make own compounds
  • evidence: microfossils
18
Q

7 major stages of evolution of living things: autotrophic prokaryotes

A
  • 2.5 - 2 billion years ago
  • selective pressure for cell advantage: make own food
  • cyanobacteria, trap solar energy in chlorophyll using photosynthesis to produce own food
  • carbon dioxide + water –> glucose + oxygen
  • production of oxygen now in atmosphere
  • from anoxic –> an oxic environment
  • evidence: stromatolites
19
Q

7 major stages of evolution of living things: eukaryotes

A
  • 1.5 billion years ago
  • organisms with membrane-bound organelles
  • hypothesise endosymbiosis: internal relationship dependant on each other
  • postulated by larger cells engulfing smaller cell –> developed relationship
  • evidence: mitochondria and chloroplasts (similar to cyanobacteria) have own DNA, endosymbiosis
20
Q

7 major stages of evolution of living things: colonial relationship

A
  • 1.5 billion years ago
  • as eukaryotic cells developed, natural selection began diversity based on immediate environment
  • some cells divided, yet some remained close together and synchronised: colonial organisms
  • eg. volvox (green algae) exists as large clump and syncs the beating of flagella (tail) to move colony
  • eg. slime mould: has individual stage but will colonise if resources deteriorate
  • evidence: still alive today: corals
21
Q

7 major stages of evolution of living things: multicellular organisms

A
  • 1 - 0.5 billion years ago
  • allowed development of plant, animals and fungi
  • 3 possiibilties:
  • loose associations between cells in colonial organisms become permanent
  • unicellular organisms undegone repeated cell divisions without cytoplasmic divisions
  • unicellular organisms undergone normal cell division but remained attached to each other to form 3D multicellular organisms
  • evidence: US! DNA, fossil record, structural anatomy
22
Q

paleontology:

A
  • study of prehistorical life through fossils
23
Q

2 types of early fossils:

A

microfossils:

  • similar to single celled prokaryotes
  • eg. bacteria and proteus

stromatolites:

  • layers of prokaryotic cells called cyanobacteria
  • called autotrophic prokaryotes (photosynthesis)
  • seen in Shark Bay
24
Q

geology:

A

study of earths crust and rocks

25
Q

3 main rock types:

A

igneous:

  • crystalline solids formed from cooling magma
  • they do contain uranium, NO LEAD
  • can be compared by levels of uranium -> lead, also to sedimentary rocks above/below
  • eg. granite NEW

sedimentary:

  • layers of debris compacted and cemented together
  • eg. limestone (crustaceans and shells) OLDEST

metamorphic:

  • rock which changes form, due to pressure
  • eg. any NO EXACT AGE
26
Q
  • how does oxygen help
A
  • iron bands in rock formations: when oxygen was first produced, made distinct red bands as iron reacted
27
Q

fossil types:

A

mould:
- imprint of ‘hollowed areas’

cast:
- copy/mineralised outline of organism

trace:
- sign of organisms’ existance (footprint, coprolite: poo)

true form:
- actual remains of organism

28
Q

law of superposition:

A
  • that youngest rocks in stratified formation are at the top, meaning fossils found in these rocks died more recently than in deeper layers
29
Q

change from anoxic to oxic environment:

A
  • evolution of photosynthesis changed environment from anoxic –> oxic, supporting most life on earth today
  • release of oxygen increased dramtically
  • allowed for dramatic expansion of eukaryote organisms
  • generally accepted all life orginated from aquatic environments, then moved to land
  • process of phtosynthesis supporting the process of respiration was a more efficient way to gain energy –> increase size and complexity of organisms –> increase to ozone layer (o3) protection from UV light, wihtout it life could only exist underwater
30
Q

What is taxonomy and why?

A
  • classification of organisms
  • easier to study
  • separate groups with similar features
  • show relationships between organisms/groups, evolutionary pathways established
  • unique names for species
31
Q

traditional biological classification:

A
  • based on MORPHOLOGY: structure of organisms and cells
  • organisms with similar morphology are grouped

advantage:

  • stays the same though life of organism
  • easy to observe
  • morphology often results of evolution, related species most likely ended in same group

eg. based on structural features, snakes, lizards, crocodiles are classified together, separate from birds
- however, DNA shows crocs and birds are more closely related than with lizards/snakes

32
Q

Cladistic classification:

A
  • use of structural criteria is being improved and extended using new information from technology:
  • electron microscope
  • DNA and biochemical studies
  • DNA and protein sequencing determine ‘relatedness’ of species in evolutionary sense
  • based more on evolutionary pathways called ‘cladistic classification’

advantages:

  • groupings are true ‘family trees’
  • as fossil discoveries and new technology reveal more details about evolutionary relationships, traditional morphological classification is becoming more cladistic
33
Q

classification hierarchy:

A 
Domain                        Dang
Kingdom                      Kevin
Phylum                        Please
Class                            Come
Order                           Over
Family                          For
Genus                          Gay
Species                        Sex
34
Q

Kingdoms:

A
  • Animalia
  • Plantae
  • Fungi
  • Protista
  • Monera: Archaea/Eurbacteria
35
Q

binomial system:

A
  • 2 naming system for species:
  • eg. human: homo sapiens
  • species from same genus are closely related, share similar characteristics
  • eg. Felis leo (lion), Felis tigris (tiger)
36
Q

what defines a species?

A
  • all higher taxon levels, body and cell structures used to separate the groups
  • same genus are similar in body structure that reproduction is used to define species

Species:
two organisms are considered belonging to same species if they normally interbreed and produce healthy fertile offspring

eg. between dogs

37
Q

classifying extinct organisms: problems

A
  • our biological classification scheme is used not only for modern species but extinct ones also
  • scientists believe 99% of species are now extinct, evidence from fossil record (imprints and remains preserved in sedimentary rock)

by classifying from fossils alone:

  • modern classification relies on cell structures at some taxons
  • most fossil imprints and cell details were not preserved
  • new DNA tech and biochemical analysis are good for ‘relatedness’ between alive organisms, but cannot be used on fossils
  • don’t have organic molecules anymore
  • very ancient/small fossils are impossible to classify with DNA samples and well preserved cellular prints
  • very rare, and most DNA samples don’t survive fossilation

Biology (9 decks)

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