Chapter 15 Flashcards
How old is earth considered to be?
4.6 billion years old
Prokaryotes
- evolve by 3.5 billion years old
- began oxygen production about 2.7 billion years ago
- lived alone for almost 2 billion years
Single-celled ________ are considered to have evolved about 2.1 billion years ago.
Eukaryotes
___________ eukaryotes are considered to have evolved approximately 1.2 billion years ago.
Multicellular
Biological history is stores __________ layers
geological
2.5 billion year-old fossilized prokaryote mats suggest that photosynthetic bacteria produced O2, which created an ___________________ important for life.
Aerobic atmosphere
These fossilized mats containing photosynthetic bacteria are called _______________.
stromatolites
This is referred to as the ____________.
Oxygen revolution
Earths early atmosphere probably contained ? 5
H2O, CO, CO2, N2 and possibly some CH4
The absence of _________ in the oldest rocks shows that there little or no O2 was present
oxidation
All organisms today arise via ___________, stating that life comes from life.
biogenesis
According to current hypotheses, the first organisms arose via chemical evolution in 3 stages.
- Collection of monomers
- Formation of RNA polymers (simple genes)
- Assembly of complement RNA (replication)
All organisms today arise via biogenesis, stating that life comes from life this is known as
Biogenesis paradox
___________ were likely synthesized from simpler molecules… this take energy.
Macromolecules
On the early Earth, it is proposed that inorganic chemicals were energized by ______ or ________ and combined to form new structures.
lighting or UV radiation
In 1953, _________ simulated what he thought was the “early earth” in his laboratory.
Stanley miller
Simple organic molecules can _________ on hot rocks or clay
polymerize
Simple organic molecules can polymerize on hot rocks or clay, this can produced ___________ and __________________.
Polypeptides and short nucleic acids
Short ___ pieces may have been acted as the 1st type of nucleic acid present on the early earth.
RNA
Polymerization of organic monomers in various situations does occur, however they are also often broken down into _______________________.
Monomers during these same processes.
If a RNA polymer formed, the catalytic ability of RNA may have lead to ______________________.
Self-replication of RNA
Short RNA molecules can act as rough templates for the formation of _________________.
Short polypeptides
can assist with RNA replication.
Polypeptides
These polypeptides can then assist with RNA replication, such assemblies may as ________. “Co-ops”
Primitive molecular cooperation.
are RNA molecules that act like enzymes.
Ribozymes
if they are placed into a aqueous (water-based) solution, they form a self-sealing sphere. why does this happen.
because phospolipids have hydrophobic tail and hydrophillic heads
This self sealing sphere may have acted like a __________________, sealing RNA and polypeptides.
primitive membrane
A protected chemical environment may have given rise to a ______________.
primitive metabolism
________, then favors those co-ops that are most efficient, and effectively reproduce (or divide)
Natural selection
Although scientists have not made life, they attest that over the course of billions of years, the correct combinations of macromolecules came together to form a simple cell, then ____________________.
Environmental pressures are responsible for the variety we see today.
Distant _________________ are used to categorize organisms into time frames when they evolved and existed on earth.
Geological eras
Radiometric dating uses _________________ which decay with predictable half-life. The 1/2 life is measured, and compared to current standards to determine the age of ancient fossils and geologic rocks.
Radioactive isotopes
According to the theory of plate tectonics……
the Earths crust is divided into giant, irregularly shaped plates that essentially float on the underlying mantle
In a process called ____________, movements in the mantle cause the plates to move.
Continental drift
Since the origin of multicellular life roughly 1.5 billon years ago, there have been three occasions in which the landmasses of earth came together to form a supercontinent called _______
Pangea
Continental drift explains the distribution of lungfishes, fossils of lungfishes are found on every continent except Antarctice, today, living lungfishes are found in south america, africa, and australia, this evidence suggest that lung fish evolved when
Pangea was still in tact
Volcanoes and earthquakes result from the movements of _____________.
Crustal plate
The boundaries of plates are hotspots of _________________.
volcanic and earthquake activitly
over the last 500 million years,
- five mass extinctions have occured
- in each event, more than 50% of the earths species went extinit
- the boundaries of plates are hotspots of volcanic and earthquake activity
When the Permian mass extinction occur
occured about 251 million years ago
What happened in the Permian mass extinction
claimed 96% of marine animals specied, and took a tremendous toll on terrestrial life, and was likely caused by enormous volcanic eruption.
In the Crataceous mass extinction what happened
caused the extinction of all the dinosaurs except birds
- was likely caused by a large asteroid that struck the Earth, blocking light and disrupting the global climate
What is adaptive radiations?
are periods of evolutionary change that
- occur when many new species evolve from common ancestor that colonized a new, unexploited area
- often follow extinction events
Radiations may result from the evolution of new adaptations such as
Wings, and adaptation for life on land in plants, insects, and tetrapods
The fossil record can tell us
- What the great events in history of life have been
- when they occured
The field of _____________________ addresses the interface of evolutionary biology and developmental biology and examines how slight genetic changes can produce major morphological differences
Evo-devo (evolution and development)
Genes that program development controls the
- rate
- timing
- spatial pattern of change in an organisms form as it develops
______________ is the retention in the adult of body structures that were juveniles features in an ancestral species.
Paedomorphosis
An example of Paedomorphosis is
the Axolotl salamande in which sexually mature adults retain gills and other larval features
Are the master control genes and determine basic features, such as where pairs of wings or legs developed on a fruit fly.
Homeotic genes
profound alternations in body form can result from
- changes in homeotic gene
- how or where homeotic genes are expressed
In the evolution of an eye or any other complex structure, behavior, or biochemical pathways, each step must
- bring a selective advantage to the organism possessing
- increase the organisms fitness
In other cases, evolutionary novelties result from the gradual adaptation of existing structures to new function, such structures that evolve in one context but become co-opted for another function are often called __________________.
exaptation
examples of expectations include
- feathers that may have first functioned for insulation and later were co-opted for flight
- flippers of penguins that first functioned for flight and were co-opted for underwater swimming.
is the evolutionary history of a species or group of species
Phylogeny
Phylogeny can be inferred from
- the fossil record
- morphological homologies
- molecular homolgies
is a discipline of biology
systematics
systematics is discipline of biology that focuses on
- classifying organism
- determining their evolutionary relationship
Carolus Linnaeus introduced ______, a system of naming and classifying species
Taxonomy
biologists assign each species a two-part scientific name or ___________.
binomial
biologists assign each species a two-part scientific name or binomial, consisting of
- a genus
- a unique part for each species within the genus
______ are grouped into progressively larger
Genera
Each taxonomic unit is a ____
Taxon
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Biologists traditionally use _______ to depict hypotheses about the evolutionary history of species
Phylogenetic tree
The branching diagrams reflect the _____________ of groups nested within more inclusive group
hierarchial classification
___________tree indicate the probable evolutionary relationships among groups and patterns of descent
Phylogenetic
