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Vocab of Ch 14, 15, 16

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The percentage of any specific allele in a gene pool
Allelic frequency
Populations in which the frequency of an alleles remains all the same over generations
Genetic equilibrium
Another mechanism that disrupts a population's genetic equilibrium is __________- the alterationon allelic frequencies by chance events
Genetic drift
______ is natural selection that favors average individuals in a population
Stabilizing selection
______ occurs when natural selection favors one of the extreme variations of a trait
Directional selection
In ______, individuals with either extreme of a trait's variation are selected for
disruptive selection
The evolution of new species, a process called
speciation
______ occurs whenever a physical barrier divides a population ex. water surrounding an island
Geographic isolation
Occurs when formerly interbreeding organisms can no longer mate and produce fertile offspring. When populations increasingly distinct, _____can arise
Reproductive isolation
Any individual or species with a multiple of normal set of chromosomes is known as _______
Polyploid
The idea that species originate through a gradual change of adaptions
Gradualism
Niles Eldredge and Stephen Gould propsed a different hypothesis known as _________. This hypothesis argues that separation occurs quickly, in rapid bursts, w/ along periods of genetic euilibrium in b/w
Punctuated equilibrium
When an ancestral species evolves into an array os species to fit a number of diverse habits, the result is called _______
Adaptive radiation
Adaptive radiation is a type of ______, the pattern of evolution in which species that once were similar to an ancestral species diverge, or become increasinglydistinct
Divergent evolution
A pattern of evolution in which distantly related organisms evolve similar traits
Convergent evolutions
______ is naturalselection that favors average individuals in a population
Stabilizing selection
Charles Darwin
• Founder of modern evolutionary theory
• In 1831 (age 21), became chief naturalist on HMS Beagle; spent next 5 years on collecting and mapping expedition to S. America and S. Pacific
• With his collection of species, was able to document both the great similarities among species found in different parts of the world, and the great biodiversity on the planet
Galapagos Islands
• Located 1000 km west of South America
• Very important to Darwin’s studies
• Saw species there that were similar to those in other places, yet uniquely adapted to life on the islands
• Darwin believed this adaptive uniqueness resulted from isolation, and convinced him of evolution
Darwin (cont.)
• Returned to England and studied for 22 more years
• Interested in essay by Thomas Malthus, suggesting that the human population was growing faster than the food supply
• Darwin believed that similar levels of competition might also exist in nature
• Also read writings of Charles Lyell (geologist) who said that geological changes tended to be very slow and uniform
Darwin’s Experiments
• Darwin also conducted selective breeding experiments using pigeons, selecting specific traits in parents to be passed on to offspring
• Felt that if humans could breed animals selectively, perhaps nature held a similar control and pressures on wild species
• Led Darwin to his theory of natural selection as a mechanism for evolution based on the survival of individuals possessing traits more favorable to their environment
Breeding organisms with specific traits in order to produce offspring with identical
artificial selection
_______ is the mechanism for the change in populations
Natural selection-> Darwin found that theory
_____ is a structural adaption that enables one species to resemble another species
Mimicry
A subtle adaption is _______, an adaption that enables species to blend with their surroundings
Camouflage
Homologous Structures
⬢ Modified structures seen among different groups of descendants
⬢ Adapted to particular environments, but retain some similarity (limbs, flippers, wings)
⬢ May be used to establish evolutionary relationships
Analogous Structures
⬢ Body structure similar in function, but different in composition
⬢ Examples include a bird wing vs. an insect wing, or a fish fin vs. a dolphin flipper
⬢ Each of the examples above evolved independently in two distantly related groups, but their forms reflect the selective pressures of their environments
⬢ May not be used to establish evolutionary relationships
Vestigial Structures
• Body structure that is reduced in function and form in the living organism, but may have been more vital in their ancestors
• Examples include sightless cave-dwelling or subterranean organisms that still have eyes, and the internal “leg” bones seen in some constrictor snakes
• Human examples are our tail (tailbone), our appendix, and our wisdom teeth
Gene pool
entire collection of genes (alleles) in a population
embryo
earliest stage of growth and developement of both plants and animals
The Earth may have cooled enought for water in the atomosphere to condense in
4.4 billion years ago
The Solar System formed about _____ bya by swirling gusts of dirt and gas
6 bya
The core of the earth is molten due to pressure and heat from _______

*Gravity compressed the dust into the earth*
radioactive decay
⬢About 3.9 bya, the ______ began to condense and precipitation formed the oceans
water vapor
This man disproved Spontaneous Generation
Francesco Redi
This man disproved spontaneous generation with microorganismd
Louis Pasteur
Francesco Redi
•Disproved spontaneous generation with experimentation
•Spontaneous generation is the idea that nonliving material can produce life
•Put meat in open jars, some covered with cheesecloth to keep flies out (but let “ethers” in)
•Maggots appeared in uncovered jars (but not in covered ones) because flies could lay eggs
whats the theory of Biogenesis
•The modern theory of living things
•Literally “beginning of life”
•Life only arises from other life
•Proven by Louis Pasteur in the late 1800’s
Louis Pasteur
⬢Louis Pasteur performed an important experiment in 1862 to help support biogenesis
⬢Used specially designed flasks with nutrient broth inside to demonstrate that contaminating bacteria came from dust, not appearing spontaneously
Aleksandr Oparin
In 1924 Oparin hypothesized that life began in the early seas ”primordial soup”
•he suggested that the sun’s energy and lightning catalyzed chemical reactions to make simple organic compounds—called “chemical evolution”
Miller and Urey
•In 1953, Miller and Urey tested Oparin’s hypothesis
•circulated steam with ammonia, methane, and hydrogen gas and sent electrical current through it to simulate lightning
•The mixture was heated and cooled to approximate daily temp changes
•After one week, they found amino acids, sugars, and other organic compounds
Miller and Urey Experiment
⬢These simple organic compounds had to be combined to form more complex molecules that are required for life
⬢Since life likely began in early shallow oceans, the reactants would be concentrated and heated which would prompt the combination of these molecules
⬢Life may have begun on surface of rocks or clay aggregates
Sidney Fox
⬢created protocells by heating amino acid solutions
⬢protocells are large ordered structures that carry out some of the activities associated with life such as growth, division, and metabolism
⬢It is thought that these protocells likely formed around bubbles by forming microspheres which acted similar to a plasma membrane
⬢It is believed that the first genetic material was RNA, because RNA does not require enzymes to make a copy, and because it is single stranded
⬢heterotrophic prokaryotes were the first true cells and they evolved from ______
Protocells

*since there was no free oxygen in the atmosphere, they had to be anaerobic *

*Competition led to the evolution of the autotrophs that were very similar to present day Archaebacteria*
_______ are prokaryotes that live in harsh conditions with little sun or oxygen such as hot sulfur springs or deep ocean vents
Archaebacteria

*They are chemosynthetic
The first photosynthetic organisms appeared later*
⬢Once the photosynthetic organisms evolved, they gave off oxygen, creating the ______ about 2.8 bya
Oxygen revolution

*This event dramatically increased the diversity of prokaryotes because aerobic organisms could evolve
By the end of the Precambrian, the oxygen content in the atmosphere was 10% of today’s levels*
When oxygen is struck by lightning, it forms _____
ozone (O3)
There are two possible explanations for the evolution of eukaryotic cells- one is infolding Hypothesis and what does it mean
inner membranes created by invagination of plasma membrane
Organelles developed when membrane folded in, creating internal compartments
There are two possible explanations for the evolution of eukaryotic cells- another one is Endosymbiont Hypothesis and what does it mean
explains the evolution of eukaryotes as a symbiotic relationship between primitive prokaryotes
______ resembles chloroplasts, and some bacteria are similar to mitochondria
Cyanobacteria
Info on Endocytosis (not a question)
it would would explain the double membrane found around these organelles
⬢Chloroplasts and mitochondria have their own ribosomes
⬢Chloroplasts and mitochondria have their own DNA, and can grow and reproduce independently of the rest of the cell
What type of rock do fossils normaly form
Sedimentary
what is a fossil
evidence of an organism that has lived in the past; may take many different forms; usually formed in sedimentary rock
what is a Paleontologist
scientist that studies ancient life
_____ is when assuming layers are not disturbed, age of artifacts may be approximated based on the sedimentary layer in which it is found
Relative dating
The method of estimating the age of something based on the amounts of radioisotopes it contains
Radiometric dating
What are trace fossils
any indirect evidence left by an animal (e.g. footprints, burrows, trails)
What is a cast
when minerals in rocks fill a space left by a decayed organism, making a replica or casts
What are molds
when an organism is buried in sediment, decays, and leaves and empty space
What is petrified
minerals penetrate and replace hard parts of organism; permineralized is similar, but empty spaces are filled with minerals
Amber is when
specimens are trapped in tree sap or ice that hardens into amber
What was pangea
when all the continents were one huge landmass with Gondwana and Laurasia about 65mya (Late Cretaceous)
What caused Pangea to move
plate tectonics
Era's in order
Precambrian Era
Paleozoic Era
Mesozoic Era
Cenozoic Era
Name the three periods in Mesozoic
–Triassic – first mammals and dinosaurs
–Jurassic – age of dinosaurs; first birds?
–Cretaceous – radiation of mammals and angiosperm plants
What happened in the Precambrian Era
• rocks date to 3.5 bya
• Accounts for 87% of world’s history
• by the end, sponges, algaes, jellyfish
• These multicellular life forms likely evolved from colonial organisms
• first orgs confined to water; easier to repro, excrete, move
• By the end of Precambrian, life had begun to move out of the oceans
• To move onto land, plant-like organisms needed:
– Waxy coating on to prevent water loss
– Transport system for water and nutrients
• Fungi appeared next, then animals with hard body coverings to prevent water loss
What happened in the Paleozoic Era
⬢ explosion of life in Cambrian period of Paleozoic
⬢ worms, echinoderms, mollusks, primitive arthropods appeared early
⬢ ferns and gymnosperms lived on land
⬢ By the end of the era, there were fish, amphibians, and reptiles (primitive)
Cenozoic Era
⬢ Golden age of mammals
⬢ Primates evolved
•Earth’s crust is broken into _______ that move on the currents present in the earth’s mantle
10 large plates (plate tectonics)
Mass extinction (info-not Question)
•at times up to 95% of the organisms on the planet were wiped out
•There have been up to 5 or 6 mass extinctions throughout earth’s history
•The largest have been at the end of the Precambrian, Permian, Cretaceous, and the one humans are currently causing
Examples of a primate
mammal like a lemur, monkey, ape, humans
Many primates are _____ which means they live in trees
arboreal (live in trees)

*early primates were small and squirrel like, evolved 65 mya*
There are two primate groups- one of them are prosimians. What are characteristics of these primates
a subgroup of primates that have small bodies and include lemurs, aye-ayes, and tarsiers
–found in tropics of Africa and SE Asia
–mouse to large house cat sized
–Nocturnal, so have large eyes
–eat seeds, insects, fruit
–evolved 50 - 55 mya
There are two primate groups- one of them are anthropoids. What are characteristics of these
•Opposable thumb - brought opposite the forefinger; human thumb larger than other primate thumbs
•Stereoscopic vision - to perceive depth and gauge distance
–Primates have excellent color vision with eyes facing forward
anthropoids traits (info)
•rounded head and flattened face due to brain size—larger cerebrum for thinking, memory, and interpretation
•feet for grasping—differ if for locomotion
•hands and feet have nails not claws
•flexible elbows
•ball and socket joints in hip and shoulder
•similar dental formula (2 1 2 3)
What are the three Major radiations in anthropoid evolution
–New World Monkeys
–Old World Monkeys
–Hominids
New world monkey have what characteristics
⬢Arboreal monkeys of South and Central America
⬢prehensile tails
⬢Include marmoset and spider monkeys
what do Old World Monkeys have
⬢Monkeys of Africa and Asia
⬢ground and tree dwellers
⬢occur naturally outside the tropics
⬢Include colobus monkey, baboons, and others
⬢use tails for balance
Hominids include what two types of animals... Also what do they do
• Hominids - humanlike bipedal primates
– includes Asian and African apes and humans (modern & ancient)
– fossil record fairly complete
• Apes - gibbons, orangutan, chimpanzee, gorilla
– no tail, very flexible hips, shoulders, and elbows
– can knuckle walk
– brain size and complexity increased
paleoanthropologist job are
to study humans
What is the order of the Australopithicus
Australopithicus anamensis
Australopithicus africanus
A. boisei and A. robustus
What is the order of the evolution of humans
Australopithicus anamensis, Homo habilis
Homo erectus
Homo Sapiens
Australopithicines
• Australopithicines (“southern ape”) are early hominids from Africa that had apelike and humanlike qualities
• First appeared about 4.2 to 3.9 mya
• All australopithicines died out about 1 mya
• Earliest was Australopithicus anamensis, which may have been bipedal
• Australopithicus afarensis was the next to evolve
• “Lucy” and other skeletons
• was bipedal, apelike brain, shoulders and forelimbs apelike
• Australopithicus africanus came next
• Fossils found by Raymond Dart in 1924
• lived 2 - 3 mya
• Had larger body and brain than A. afarensis
• About 2 mya, A. boisei and A. robustus appeared
• more developed Australopithicines, but didn’t evolve into modern humans, so many classify them as Paranthropus now
Homo habilis
•found in 1964 by Louis and Mary Leakey
•Means “handy man” because first to use stone tools
•Appeared 1.5 – 2 mya
•larger braincase, teeth and jaw smaller than Australopithicines
Homo erectus
• “upright man”
• evolved from Homo habilis
• appeared 1.8 - 1.6 mya
• larger brain, more humanlike face, larger brow ridges, no chin
• Better tools, used fire, lived in caves
• migrated out of Africa about 1 mya, spread throughout Africa and Asia—extinct 300,000 to 500,000 ya (eg Peking man, Java man)
Homo Sapiens
⬢ Modern humans; appeared 100,000 to 400,000 ya in Europe, Africa, Middle East and Asia
⬢ less prominent brows, more bulging foreheads, smaller teeth
⬢Two different subspecies of Homo Sapiens existed prior to the modern form, but one became extinct
Cro-magnons
⬢ Homo sapiens subspecies that lived from 120,000 to 35,000 ya
⬢ Very similar to modern humans, and eventually evolved into modern H. sapiens
⬢ Extensive tool use, cave paintings, had language and social structure
Neandertals
⬢An extinct side branch of H. sapiens that lived from 230,000 to 35,000 ya in Europe, Asia, and Middle East
⬢First discovered in Neander Valley of Germany
⬢thick bones, large face, prominent nose
⬢lived in caves during the ice age of Pleistocene period
⬢first to bury their dead, suggesting spiritual beliefs
⬢Were able to speak and had diverse tools
⬢Cause of extinction is unknown, but did not evolve into modern humans
multiregional hypothesis
- various H. sapiens evolved from H. erectus in different parts of the world

*Dont know which one is correct*
⬢out of Africa hypothesis
H. sapiens evolved from H. erectus in Africa and migrated out

*Dont know which one is correct*
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