Unit 6 Evolution Flashcards
(99 cards)
1
Q
Pre-Cambrian Supereon starting and ending dates
A
Starting Date: 4.6 billion years ago (beginning of Earth)
Ending Date: 570 million years ago (start of the Cambrian Period)
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Q
Phanerozoic eon starting and end dates
A
570 million years ago-present
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Q
Paleozoic era starting and end dates
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570 million years ago- 245 million years ago
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Q
Mesozoic era starting and end dates
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245 million years ago- 66 million years ago
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Q
cenozoic era starting and end dates
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66 million years- to present
6
Q
formation of life
A
life began on Earth with the earliest microorganisms.
7
Q
date formation of life occur
A
3.5-4 billion years ago
8
Q
oxygen revolution
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Photosynthetic bacteria (like cyanobacteria) began producing oxygen, leading to a dramatic increase in Earth’s oxygen levels.
9
Q
oxygen revelution date
A
2.4 billion years ago
10
Q
cambrian explosion
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A sudden diversification of life forms, with most major animal phyla appearing in the fossil record. in oceans
11
Q
cambrian explosion date
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540 million years ago
12
Q
First terrestrial life
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The first plants and fungi began colonizing land, followed by early animals.
13
Q
first terrestrial life date
A
475 million years
14
Q
permian extinction
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The largest mass extinction event, wiping out around 90% of marine species and many terrestrial species.
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Q
permian extinction date
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happened about 252 million years ago
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Q
K-T event
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wiping out the dinosaurs, along with many other species, likely caused by a massive asteroid impact.
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Q
K-T event date
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66 million years ago
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Q
Separation of Pangaea
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the giant supercontinent slowly started to break apart into the continents we have today.
19
Q
starting date of seperation of pangea
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200 million years ago
20
Q
Movement of Primates out of trees onto land
A
Early primates evolved to walk on the ground, leading to the development of bipedalism and eventually humans.
21
Q
date of Movement of Primates out of trees onto land
A
7 million years ago
22
Q
Panspermia
A
Life on Earth may have originated from microorganisms or organic molecules that came from space, possibly through comets or meteorites. Essentially, life could have been “seeded” on Earth from extraterrestrial sources.
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Q
Pasteur
A
No microorganisms grew in the sealed flask, while the open flask grew microorganisms, proving that life does not arise spontaneously but from other life.
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Q
Redi
A
This experiment helped disprove the idea that life could spontaneously generate from non-living matter, showing that life comes from other life.
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Miller and urey
In 1953, Stanley Miller and Harold Urey simulated early Earth conditions (such as lightning and volcanic activity) in a laboratory and showed that amino acids could form from simple molecules like methane, ammonia, and hydrogen. This provided evidence for how life’s building blocks might have formed on early Earth.
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major concepts and mechanisms of Darwin’s theory of evolution by means of natural selection
Every population has phenotypic variation between individuals
Environmental factors favor some variations such that they increase the ability of the individuals to reproduce
These “selected” variations may be heritable and can become more frequent in the population over time
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variation
differences in characteristics among individuals of the same species
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adaptation
heritable trait that increases an organism's ability to survive and reproduce in an environment
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fitness
how well an organism can survice and reproduce in its environment
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natural selection
organisms that our most suited to their environment survive and reproduce most successfully
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differential reproduction
means that some individuals are more successful at surviving and reproducing than others because of their traits.
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selective pressure
factors in the environment (like food, predators, or climate) that influence which traits are helpful for survival and reproduction.
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common ancestry
darwin proposed that living species descended with changes over time from a common ancestor
A single species over time can turn into multiple species
Darwin created a tree linking living things together (tree of life)
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Malthus
if the human population grew unchecked there would not be enough living space and food for everyone
war famine and disease work against population growth
this made darwin think which individuals survive and why
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Lyell
-He wrote the principles of geology
-Laws of nature are constant over time, -argued that earth is much older than a couple thousand years
-This made darwin wonder if earth could change over time, could life change too
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Wallace
Independently proposed a theory of natural selection, prompting Darwin to publish his work.
His work contained the proper hypothesis but darwin had the evidence to support the hypothesis
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lamarck
Individual organism could change during their lifetime by selectively using or not using various parts of there bodys
Individuals could pass these acquired traits on to their offspring, enabling species to change over time.
Organisms change and acquire traits that help them live more successfully in their environments
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Contrast original Darwinian theory with neodarwinism
Darwin's Theory: Emphasized natural selection acting on variation within populations without understanding genetics.
Neo-Darwinism: Integrates genetics with natural selection, understanding how genes mutate and how they are passed down, providing a molecular mechanism for evolution.
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Hardy-Weinberg Equilibrium
no change in allele frequency
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Why will organisms never exhibit hardy weinberg equillibrium
Populations rarely ever exhibit many of the characteristics of HW Equilibrium
Mutations and environmental change are random
Alleles that code for adaptations may be reduced to variations in a new environment
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Directional mode of naturals selection
One extreme trait is favored. This causes the population’s traits to shift toward that extreme.
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directionial mode of natural selection in the poecillia lab
What it is: One extreme trait is favored.
In guppies: Bright-colored males might be more attractive to females → more babies.
Result: More bright-colored guppies over time
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stabilizing mode of natural selection
The average trait is favored, and extremes are selected against. This keeps the population's traits stable.
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stabilizing mode of natural selection related to the poecillia lab
Example: Medium-colored guppies survive better.
Why: Too bright = eaten by predators 🐟
Too dull = ignored by females 🚫
Result: Most guppies stay medium-colored.
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disruptive mode of natural selection
Both extreme traits are favored, and the average trait is selected against. This can lead to two distinct groups in the population.
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disruptive mode of natural selection related to poecillia lab
Example: Both very bright and very dull guppies do well.
Why: Bright ones get mates 💕, dull ones avoid predators 👻
Medium ones lose both ways.
Result: More super bright AND super dull guppies. Fewer in-between.
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Allopatric speciation
A population is physically split into two groups due to geographic isolation
If the two environments are different, the selective pressures on each sub-population will differ
Differential reproduction will result as different variations are favored in each environment
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Peripatric speciation
a small group of individuals becomes isolated at the edge of a larger population,
often due to a geographic barrier.
Over time, the small group experiences different environmental pressures, leading to the development of new traits and eventually forming a new species.
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sympatric speciation
occurs when a new species forms within the same geographic area as its ancestor, without physical barriers. This can happen due to factors like changes in behavior, diet, or mating preferences, leading to reproductive isolation even though the populations still live in the same place.
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Fossil record
collection of all the fossils ever found, which shows how life on Earth has changed over a long time.
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intact remain fossil
Actual organism embedded in ice or amber
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Petrification fossil
Cellulose of plant or bacterial matter binds to tetravalent silica
Gradually, the cellulose decomposes, leaving behind the silica
The primary mode of fossilization for species from dry environments
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Permineralization
When an organism dies, it is covered in sediment
As the organic matter decays, a pore or space is left in the sediment
Inorganic minerals leach into the pore and solidify in the shape of the original organism
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Compression Fossil
Generally associated with plants
As plant dies in a layer of fine sediment, it is compressed in the perpendicular plane
Organism decays, leaving behind an impression or imprint
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Homologous structures
Similar structures in different species that have a common evolutionary origin (e.g., the bones in the limbs of humans, whales, and bats). These structures suggest that these species share a common ancestor.
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analogous structures
Structures in different species that serve similar functions but have different evolutionary origins (e.g., wings of a bird and a butterfly). This shows that similar environmental pressures can lead to similar adaptations.
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vestigial structures
Reduced or non-functional structures in an organism that were functional in an ancestor (e.g., the human appendix or whale pelvic bones). These structures suggest evolutionary remnants of traits that were once useful.
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Molecular clock hypothesis
N = amount of time for one nucleotide in a protein to mutate, then we can calculate when two species diverged as…
(N) (# of mis-paired nucleotides) = Time
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Embryological in evolution
Similarities in the early development (embryos) of different species suggest a common ancestry. For example, vertebrate embryos (humans, chickens, fish) look similar in early stages, which supports the idea of a shared evolutionary origin.
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Genetic in evolution
DNA comparisons between different species show how closely related they are. The more similar the DNA, the more closely related the species. Genetic evidence supports the theory of common descent and provides a molecular basis for evolution.
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Linnaeus
binomial nomenclature is that species are assigned a two part name
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Taxonomy
-system of naming and classifying organism based on sharing characteristics and universal rules
-Each name must reserve to only one species
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5 kingdoms
Organisms are sorted into 5 kingdoms, plantae, animalia, protista, monera,
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order of things
fungi
Species(most specific)
Genus
Family
Order
Class
Phylum
Kingdom(most broad, contains many species)
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Phylogeny
study of evolutionary relationships among organisms
Goal is to group organisms into larger categories that reflect lines of evolutionary descent
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Clade
branch of a cladogram that includes a single ancestor and all its descendants
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Cladistic analysis
compares selected traits to determine the order in which groups of organisms branched off from their common ancestor
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cladegram
links groups of organisms by showing current hypotheses about how evolutionary lines branched off from a common ancestor
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Parsimony Principle
a method used to choose the simplest explanation for how species are related. It suggests that, when faced with multiple possible explanations, the one with the fewest assumptions or steps is preferred.
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Arborreal
Refers to tree-dwelling life. Early primates likely lived in trees, with adaptations such as grasping hands and feet, and flexible limbs.
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terrestrial
Refers to life on the ground. Over time, some primates transitioned to living on the ground, which led to adaptations for bipedalism (walking on two legs), such as changes in the pelvis, spine, and legs.
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Prosimians
primates that are least related to humans
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Specific variations/adaptations leading to modern human anatomy/physiology
Bipedalism: The shift to walking on two legs required major changes in human anatomy, such as the development of a curved spine, changes in the shape of the pelvis, and the alignment of the lower limbs.
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apomorphic trait
a characteristic that has evolved in a species and is different from what its ancestors had. It's a new feature that shows up in a group of organisms, helping them stand out or adapt to their environment
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founders effect
a small group of individuals from a larger population starts a new population, and their genetic makeup may not represent the original population's diversity.
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Bottleneck effect
The bottleneck effect happens when a small group of organisms survive a disaster, and their limited genetic variety affects the whole population.
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parapatric speciation
when two populations are next to each other, but they do not completely overlap. There is some gene flow between them, but they evolve differently because of environmental differences along the border.
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divergent evolution
organisms start as the same species but they become two different species due to things such as different environments. share a common ancestor
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convergent evolution
different species that evolve similar traits. due to living in similar environments.
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gradualism
slow gradual changes in alleles/phenotypes over time that show little change
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punctuated equillibrium
species stay the same for long periods, but change quickly in short bursts due to environmental shifts or new challenges.
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Natural vs artificial selection
Natural Selection
-Nature chooses.
-Animals with the best traits for survival live and have babies.
Example: Fast rabbits escape predators and have more babies.
Artificial Selection
-Humans choose.
-People pick animals or plants with traits they like and breed them.
Example: Humans breed dogs to be small or fluffy.
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aquired characteristics vs adaptation
Lamarck (Acquired Characteristics)
-Believed animals change by using body parts more.
Example: Giraffes stretch necks → long necks passed to babies.
Darwin (Adaptation by Natural Selection)
-Believed some are born with helpful traits.
Example: Giraffes born with longer necks survive better → have more babies.
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apomorphic trait
new trait
Shows up after evolution happens
Helps tell apart newer species from older ones
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plesiomorphic trait
Old or ancestral trait
Inherited from a distant ancestor
Shared by many related species
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allele frequency vs gene pool in terms of neodarwinism
In Neo-Darwinism, the gene pool is all the genes in a population, like a big bucket of traits. Allele frequency is how common a specific version of a gene is in that bucket. Evolution happens when those allele frequencies change over time, meaning the population is evolving.
87
what occured during the archeozic era
-formation of earths crust
-formation of life
-little to no oxygen
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archeozic era starting and end date
4 billion to 2.5 billion years ago.
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what occured during the second part of the precambrian supereon
2.5 bya- 540 bya
-the oxygen revolution
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biogenesis
life comes from pre-existing life, meaning living organisms only arise from other living organisms.
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abiogenesis
life originated from non-living matter, such as chemicals in the early Earth forming simple life forms.
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lazarus species
a species that was thought to be extinct but was later rediscovered
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ecomorphs
a local variety of a species whose appearance is determined by its ecological environment.
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divergent evolution vs speciation
Divergent evolution = species getting more different.
Speciation = a species splitting into new species.
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compute number of difference that should exist between individuals using molecular clock hypothesis.
( mount of time for one nucleotide in a protein to mutate)(# of mis-paired nucleotides) = Time
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elvis species
a species that you thought was alive but is actually dead
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two parts of binomial nomanclature
Genus – The first part, which is capitalized, identifies the broader group of species.
Species – The second part, which is lowercase, identifies the specific species within the genus.
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expiriments that disproved abiogenesis
-pasteurs
-miller and urey
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why is panspermia an attractive theory based on the archean time period
it suggests that life could have originated elsewhere in the universe and been transported to Earth, providing an explanation for the sudden appearance of life during a time when the early Earth’s conditions may not have been suitable for abiogenesis.
