Chapter 25/26 Flashcards
Phylogeny
an evololutionary tree
How is evolutionary history reconstructed?
- fossil record
- comparison of living species
- homologous traits
- analogous traits
- molecular comparisons
- geological time
homologous traits
similar because they wer inherited from a common ancestor
analogous traits
similar, but evolved independently
clade
a grouping that includes a common ancestor and its descendents on a phylogeny tree
forms a nested hierarchy
Eras
Paleozoic, Mesozoic, Cenozoic
Precambrian Era
life arose sometime in this area - 3.5 bya oldest fossils
What is the earliest fossil?
prokaryote
What were the first cells?
protocells
have not been produced in a lab
they are droplets with membranes that have a different internal chemistry than their environment
clay greatly increases the rate of vesicle self-assembly
endosymbiotic theory
explains mitochondria and chloroplasts
eukarote engulfing photosynthetic prokaryote.
Key evidence for endosymbiotic theory
- inner membranes are similar to plasma membranes of prokaryotes
- division is binary fission
- thiese organelles have their own DNA (circular) and transcribe and translate it
- their ribosomes are more similar to prokaryotic than eukaryotic ribosomes
cyanobacteria
photosynthesis adds oxygen to asmosphere
first organism to add oxygen to atmosphere
Eukaryotes
have a cytoskeleton
allows them to change shpae and engulf other cells (get food and digestion)
Horizontal gene transfer
sharing of genes from one cell to another
- most recent common ancestor of all living things
- between mitochondrial ancestor and ancestor of eukaryotes
- chlooplast ancestor and ancestor of green algae
happened a few times with different plastids
advantages of multicellularity
escape from predation, specialization of cells for increased efficiency
single-celled organisms stick together to form colonies
choanoflagellate colony
share common ancestor with animals, but didn’t become animals
unicellular choanoflagellates have the genes for:
collagen, structural proteins in animals
cell adhesion proteins hold cells together
cell communication proteins
Burgess Shale Fossils: Ediacaran Fauna (aquatic)
all common animals started here
(animals in the pre-cambrian period)
Paleozoic Era
Cambrian Period
Evolutionary innovations
gut with 2 openings (allows specialization, can take in more food)
complex nervious system (cephalization - development of head)
shells and exoskeletons (start to see armor)
fish (500mya), amphibians (450mya), reptiles (250mya)
ended with major extinction (90% of all species disappear
Pangea forms
Mesozoic period
“Age of Reptiles”
cone-bearing and flower-bearing plants co-evolved with insects
dinosaurs
homeothermy
vertebrate flight (convergent evolution)
ends with major extinction (50% of all species disappear)
Extinction of Mesozoic
meteorite 10 km across under water
iridium common in meteorites, but not on earth
extinction because a layer cloud of debris blocked sunlight and disrupted climate for several months
volcanic acitivity of Deccan Traps in India
spew lava and ash
CO2 warms the global climate
temp dif between poles and equator slow mixing of ocean water
drop in O2 levels in oceans
select for anaerobic bacteria that prodcue H2S
H2S is toxic and destroys ozone shield
Cenazoic
65mya-today
“Age of Mammals”
adaptive radiation
macroevolutionary changes
Adaptive radiation occurs when:
many vacant niches
major evolutionary innovation
colonized regions with little competition
Macroevolution
a pattern of evolution above the species level
big changes
ex: emergence of terrestrial vertebrates through a series of speciation events, impact of mass extinctions of the diversity of life, and the origin of key adaptatios (like flight in birds)
Mechanisms of Macroevolutionary change
mutations that change the sequence and regulation of developmental genes
Hox genes
Heterochrony
change the relative growth rate or time of different body parts during development
can cause paedomorphosis
paedomorphosis
the sexually mature stage retains juvenile structures of an ancestral species
Evolution is not goal oriented
random mutations cause genetic diversity
complex structures have evoved in increments from simpler versions that were of use to the organism (sometimes for the same function and sometimes for different functions)
exaptation
first used for a different purpose
ex. feathers
Formation of eye
gradual changes can result in complex structureEach stage must provide advantage to organism
The Hox Genes
duplicate the gene
use gene that controls spatial organization of body parts
Homeotic (Hox) genes control identity of appendages by regulating other genes
Idea: major changes in body form can be made by mutations in the regulation of developmental genes not their sequences
each branch point
represents the divergence of 2 species
sister taxa
groups that share an immediate common ancestor
outgroup
outlier of a common ancestor. relative.
used to describe evolutionary relationships
characters shared by the outgroup and ingroup are ancestral characters that predate the divergence of both groups froma common ancestor
stromatolites
3.5bya, still around
layered rocks that from when certain prokaryotes bind think layers of sediment together
Miller-Urey type experiments
demonstrate abiotic synthesis of organic molecules is possible under various assumptions about the composition of the early earth
Nature of first genetic material and why
catalytic reactions of ribozymes formed RNA
RNA molecules with certain base sequences are more stable and replicate with fewer errors than other sequences
Sedimentary rocks
formed from sand and mud that settled at the bottom of aquatic habitiats and are the richest source of fossils
How does radiometric dating work?
Isotypes of radioactive elecments slowly decay into other isotopes. The rate is measured in half-lives, which is the amount of time it takes for half of the parent isotope to decay. The amount of these elements remaining in a fossil can be used to determine how old the fossil is.
When did oxygen begin to accumulate in the atomosphere, what molecule produced it, what process?
2.7-2.3 bya gradually increased, water, photosynthesis
Cambrian Explosion
535-525 mya
When many present-day animal phyla suddenly appeared in fossil form
What adaptations allowed plants to colonize
adaptations that made it possible to reproduce on land and prevent dehydration
for plants, they have a vascular system for transporting materials internally and a waterproof coating of wax on their leaves to slow loss of water
What was the first group of animals to colonize land?
anthropods
What causes continental drift, when was the last supercontinent?
The continents are throught to float on the mantle, so when the mantle moves, it causes continental drift.
about 250mya Pangea
an evololutionary tree
Phylogeny
- fossil record
- comparison of living species
- homologous traits
- analogous traits
- molecular comparisons
- geological time
How is evolutionary history reconstructed?
similar because they wer inherited from a common ancestor
homologous traits
similar, but evolved independently
analogous traits
a grouping that includes a common ancestor and its descendents on a phylogeny tree
forms a nested hierarchy
clade
Paleozoic, Mesozoic, Cenozoic
Eras
life arose sometime in this area - 3.5 bya oldest fossils
Precambrian Era
prokaryote
What is the earliest fossil?
protocells
have not been produced in a lab
they are droplets with membranes that have a different internal chemistry than their environment
clay greatly increases the rate of vesicle self-assembly
What were the first cells?
explains mitochondria and chloroplasts
eukarote engulfing photosynthetic prokaryote.
endosymbiotic theory
- inner membranes are similar to plasma membranes of prokaryotes
- division is binary fission
- thiese organelles have their own DNA (circular) and transcribe and translate it
- their ribosomes are more similar to prokaryotic than eukaryotic ribosomes
Key evidence for endosymbiotic theory
photosynthesis adds oxygen to asmosphere
first organism to add oxygen to atmosphere
cyanobacteria
have a cytoskeleton
allows them to change shpae and engulf other cells (get food and digestion)
Eukaryotes
sharing of genes from one cell to another
- most recent common ancestor of all living things
- between mitochondrial ancestor and ancestor of eukaryotes
- chlooplast ancestor and ancestor of green algae
happened a few times with different plastids
Horizontal gene transfer
escape from predation, specialization of cells for increased efficiency
single-celled organisms stick together to form colonies
advantages of multicellularity
share common ancestor with animals, but didn’t become animals
choanoflagellate colony
collagen, structural proteins in animals
cell adhesion proteins hold cells together
cell communication proteins
unicellular choanoflagellates have the genes for:
all common animals started here
(animals in the pre-cambrian period)
Burgess Shale Fossils: Ediacaran Fauna (aquatic)
Evolutionary innovations
gut with 2 openings (allows specialization, can take in more food)
complex nervious system (cephalization - development of head)
shells and exoskeletons (start to see armor)
fish (500mya), amphibians (450mya), reptiles (250mya)
ended with major extinction (90% of all species disappear
Pangea forms
Paleozoic Era
Cambrian Period
“Age of Reptiles”
cone-bearing and flower-bearing plants co-evolved with insects
dinosaurs
homeothermy
vertebrate flight (convergent evolution)
ends with major extinction (50% of all species disappear)
Mesozoic period
meteorite 10 km across under water
iridium common in meteorites, but not on earth
extinction because a layer cloud of debris blocked sunlight and disrupted climate for several months
volcanic acitivity of Deccan Traps in India
spew lava and ash
CO2 warms the global climate
temp dif between poles and equator slow mixing of ocean water
drop in O2 levels in oceans
select for anaerobic bacteria that prodcue H2S
H2S is toxic and destroys ozone shield
Extinction of Mesozoic
65mya-today
“Age of Mammals”
adaptive radiation
macroevolutionary changes
Cenazoic
many vacant niches
major evolutionary innovation
colonized regions with little competition
Adaptive radiation occurs when:
a pattern of evolution above the species level
big changes
ex: emergence of terrestrial vertebrates through a series of speciation events, impact of mass extinctions of the diversity of life, and the origin of key adaptatios (like flight in birds)
Macroevolution
mutations that change the sequence and regulation of developmental genes
Hox genes
Mechanisms of Macroevolutionary change
change the relative growth rate or time of different body parts during development
can cause paedomorphosis
Heterochrony
the sexually mature stage retains juvenile structures of an ancestral species
paedomorphosis
random mutations cause genetic diversity
complex structures have evoved in increments from simpler versions that were of use to the organism (sometimes for the same function and sometimes for different functions)
Evolution is not goal oriented
first used for a different purpose
ex. feathers
exaptation
gradual changes can result in complex structureEach stage must provide advantage to organism
Formation of eye
duplicate the gene
use gene that controls spatial organization of body parts
Homeotic (Hox) genes control identity of appendages by regulating other genes
Idea: major changes in body form can be made by mutations in the regulation of developmental genes not their sequences
The Hox Genes
represents the divergence of 2 species
each branch point
groups that share an immediate common ancestor
sister taxa
outlier of a common ancestor. relative.
used to describe evolutionary relationships
characters shared by the outgroup and ingroup are ancestral characters that predate the divergence of both groups froma common ancestor
outgroup
3.5bya, still around
layered rocks that from when certain prokaryotes bind think layers of sediment together
stromatolites
demonstrate abiotic synthesis of organic molecules is possible under various assumptions about the composition of the early earth
Miller-Urey type experiments
catalytic reactions of ribozymes formed RNA
RNA molecules with certain base sequences are more stable and replicate with fewer errors than other sequences
Nature of first genetic material and why
formed from sand and mud that settled at the bottom of aquatic habitiats and are the richest source of fossils
Sedimentary rocks
Isotypes of radioactive elecments slowly decay into other isotopes. The rate is measured in half-lives, which is the amount of time it takes for half of the parent isotope to decay. The amount of these elements remaining in a fossil can be used to determine how old the fossil is.
How does radiometric dating work?
2.7-2.3 bya gradually increased, water, photosynthesis
When did oxygen begin to accumulate in the atomosphere, what molecule produced it, what process?
535-525 mya
When many present-day animal phyla suddenly appeared in fossil form
Cambrian Explosion
adaptations that made it possible to reproduce on land and prevent dehydration
for plants, they have a vascular system for transporting materials internally and a waterproof coating of wax on their leaves to slow loss of water
What adaptations allowed plants to colonize
anthropods
What was the first group of animals to colonize land?
The continents are throught to float on the mantle, so when the mantle moves, it causes continental drift.
about 250mya Pangea
What causes continental drift, when was the last supercontinent?
