evolution- biology

evidence for evolution

FOSSILS -found in sedimentary rock -Dating fossils: - relative dating: layers of rock, oder fossils found in lower levels -radioactive dating : uses radioactive isotopes of elements, depends on the half life of isotopes (time taken by 1/2 the radioactive isotope to convert to nonradioactive element) COMPARATIVE MORPHOLOGY -homo. structures: similar organs from common ancestors but modified to adapt to lifestyle. ex:wings of bat, wings of bird, flipper of whale -Analogous structures: different origins, very distant ancestors, structures help to adapt to similar environment ex: wing of butterfly, wing of bat/bird COMPARATIVE EMBRYOLOGY ANATOMICAL EVIDENCE -vestigial structure: have no apparent function, but resemble structures their ancestors possessed ex: human appendix

Primordial soup

Formed by Haldane from oparin's theory •life began in a pond or an ocean

Natural Selection

the process whereby individuals that are better suited to their environment survive and reproduce more successfully ; Darwin nicknamed it Survival of The Fittest

Protocells

Precursors to the first true cells ; liquid protein membrane

evolution

change over time, the process by which modern organisms have descended from ancient organisms

Artificial Selection

choosing to breed coma that produce that most milk or the fastest horses

Charles Lyell & James Hutton

uniformatarianism: long term geological processes were responsible for shaping the earth's surface and they are still taking place now

Modern synthesis

darwin theory supported by genetics

Disruptive Selection

- In which of these is the fitness of individuals at the extreme ends higher than that of individuals in the middle -a population of birds lives in an area where plants with medium sized seeds are wiped out by a fungal infection. birds with unusually large or small beaks would have higher fitness than those with medium sized beaks. Over time the population splits into two subgroups; one that eats small seeds and one that eats large seeds.

Directional Selection

- in which of these is the fitness of individuals at one end of the normal distribution curve higher than that of individuals in the middle or at the other end of the curve - Birds with bigger, thicker beaks can feed more easily on large, harder seen. A food shortage causes the supply of small and medium seeds to run low, leaving only larger seeds. Birds with bigger beaks show greater fitness than birds with medium or small beaks. Over time more birds with bigger beaks survive and reproduce. -the orange and black pattern of a Monarch butterfly serves as a warning to sharp-eyed birds that the Monarch is poisonous to eat and tastes bad. Individuals with the brightest color pattern were more likely to warn off birds and survive to reproduce than those with a dull or medium color pattern. over time and many generations, the monarch population became more brightly-colored.

Stabilizing Selection

-In which of these is the fitness of individuals in the middle higher than that of individuals at the extreme ends. - Human babies born smaller than average are likely to be less healthy and less likely to survive. larger than average babies are likely to have difficulty being born. the fitness of these larger or smaller weight babies is lower average than average-sized babies os human babies tend to born of average size. -in birds, feather color among males is more likely to attract a mate, but also more likely to attract a predator. over time and many generations, the highest frequency color is for males with medium colors, while makes with very dull colors and males with very bright colors became increasingly rare.

adaptive radiation- EXAMPLES

-whales sharks and penguins all have streamlined bodies and appendages for moving in water even though they belong in different classes of animal classes -hummingbirds have a beak just the right length to reach the nectar in a cardinal flower and as they feed their foreheads bump into the pollen structure. Cardinal flowers are red which hummingbirds can see but bees can't and their pollen structure is at just the right height for the hummingbird to pick up pollen as it feeds. -the Galapagos finches evolved through natural selection from a common ancestor into a wide variety of different looking species with different kinds of beaks -ostriches are native to the savannahs of Africa, while penguins live in the polar regions. although ostriches and penguins are closely related, the look very different -also called divergent evolution

evidences that support Darwin's theory of Evolution

1) Fossils 2) Comparative Embryology 3) Comparative Anatomy/Homologous structures 4) Vestigial Structures 5) molecular (DNA) 6) Biogeography (distribution) 7) Molecular (proteins)

Five components of evolution

1) nonconstancy of species (individuals are unique) 2)all organisms descent from common ancestors 3) gradualness of evolution 4)Multiplication of species (diversity) 5) natural selection

Inheritance of Acquired traits

A giraffe that stretches its neck longer by reaching for food and then passes this long-necked trait on to offspring is on example of this

Sydney Fox

Generated proteinoids (formation of cells)

microevolution

is the change in allele frequencies that occurs over time within a population

Punctuated Equilibrium- EXAMPLE

Horse evolution shows long stable periods of little evolution interrupted by brief periods of rapid change

Liposomes

Pure lipid; form spontaneously in liquid environments

Descent with Modifications

The ideas that each living species has descended with changes over time from other species

Evolution

The progressive change in organisms over time

species

a group of individuals that actually or portentially interbreed in nature

adaptation

a heritable trait that enables organisms to survive and reproduce

Founder Effect

a situation in which the allele frequencies change as a result of the migration of a small subgroup of individuals

theory

a well supported, testable explanation of phenomena that have occurred in the natural world.

Adaptation

any inherited characteristics that increases an organisms chance of survival, like webbed feet, sharp claws, or speed

Mass extinction -EXAMPLE

at the end of the Cretaceous period an asteroid hit the earth causing the loss of many species including the dinosaurs

George Cuvier

catastrophism: species extinction due to catastrophic event

Linnaeus

created talons-groups of organisms with similar traits -Kingdom -Phylum -Class -Order -Family -Genus -Species

Hardy-Weinberg theorem

criteria required: -no genetic drift -no natural selection -no gene flow (no migration) -random mating -population size large -no mutations

pryzygotic

ecological temporal behavioral mechanical gamete

extrinsinc factors

environmental forces beyond the control of the population -allopatric speciation: geographic isolation (physical barriers)

Gradualism

evolution happening slowly over a long period of time

Charles Lyell

explained that the geological processes seen happening on the Earth now have shaped Earth's geological features over long periods of time

Vestigial Organs

homologous structures that are so reduced in size that they no longer function, like the human appendix or legs in skinks

postzygotic

hybrid inviabillty, sterility, collapse

Inttrinsic factors

internal choices, preferences, inherit in the population -sympatric speciation: -reproductive isolation - pryzygotic - post zygotic

geogenesis

life first formed on Earth

panspermia

life first formed somewhere else and was transferred to earth

Struggle for Existence

members of each species compete regularly for food and other necessary resources

mechanisms for evolution

mutation, migration, genetic drift, and natural selection

3 conditions necessary for evolution by natural selection to occur

natural variability for a trait in a population trait must be heritable trait must lead to differential reproduction

Divergent Evolution

organisms with common ancestors BUT adapted to live in diverse conditions Even though the Galapagos finches share a common ancestor, they have evolved to fit the ecosystems of their islands Adaptive Radiation: another name for divergent evolution

Convergent Evolution -EXAMPLE

ostriches and giraffes are not native to the savannah of Africa. they share the same characteristics of a very long neck.

Thomas Malthus

predicted that the human population would grow faster than the resources needed to sustain it.

James Hutton

proposed that the Earth is shaped by geological forces over extremely long periods of time, and that the earth is very old.

Jean-Baptiste Lamarck

proposed that the selective use or disuse of an organ led to a change the organ that was then passed on to the offspring; evolution by acquired characteristics (proved wrong)

Alfred Wallace

published his own theory of evolution by natural selection about the same time as Charles Darwin

genetic drift

random changes in the gene frequencies of a population from generation to generation. has the effect of decreasing genetic variation within a population

natural selection

the process in which some individuals have traits that improve survival or reproduction

cladogenesis

splitting of a species into two or more groups that diverge in their traits -branching

Homologous Structures

structures that have different mature forms but develop from the same embryonic tissues

creationism

superior being created life on earth

Fitness

the ability of an individual to survive and reproduce in tis specific environment

Common Descent

the ideas that all species- living and extinct- were derived from common ancestors linked by a single "tree of life"

Convergent Evolution

the independent development of similar structures in organisms that are not directly related Dolphins, penguins, and sharks are distantly- related species that share similar characteristics which help them live in water is an example -usually seen in animals and plants that live in similar environments.

gene flow

the movement of genes from one population to another

Natural Variation

the natural differences between individuals of species

speciation

the origin of new species

macroevolution

the origin of new taxonomic groups

Fossils

the preserved remains of ancient organisms that provide evidence for how life has changed over time.

anagenesis

the transformation occurring within a single lineage as a population develops new characteristics -sequential

Charles Darwin

was an English naturalist who made numerous observations during his travels on the Beagle which led him to pose a hypothesis about how life changes overtime

Galapagos Islands

where Charles Darwin observed finches and turtles that led to his theory of evolution

Oparin

worked with Geogenesis -worked on coacervates: tiny spherical droplet of assorted organic molecules (specifically liquid molecules) which is held together by hydrophobic forces. -Theory: -oceans were hot -atmosphere was made of ammonia, hydrogen, methane and water vapor -energy from lightning and the sun caused these gases to combine and fall into the hot seas -combined gases became more complex, eventually forming simple forms of life

Stanley millers experiment

•conducted by Miller and Urey -gases used were Methane ammonia hydrogen and water -electric currant to stimulate lightning -end of one week 10-15% of the carbon was organic compounds -2% of the carbon formed amino acids -this experiment showed that organic compounds such as amino acids, essential to cellular life, could be made easily under the conditions that scientists believed to be present on the early earyh