Chapter 22 - Evolution

-South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe. - The plants travelled to islands and then adapted.

herbivory, having animals develop to eat plants

Aristotle

Cuvier, father of paleontology

-Individuals in a population vary in their heritable traits -Organisms produce more offpspring than the environment can support.

-Organisms have the capacity to overreproduce.

dissimilar organisms might have evolved from a distant, common ancestor

closely related organisms have more similar DNA and proteins

is a favorable trait in response to the environment in a species

-the fossil record of the evolution of modern cetaceans

-origin focused biologists attention to great diversity of organisms -current species are descendants of ancestral species -organisms evolved instead of were created, over a long period of time - descent with modification -organisms changed in genetic composition from generation to generation -there is pattern and process to evolution

Patterns of evolution are revealed by DATA.

Consists of mechanisms that we can observe that produce a pattern of change. Process produces pattern.

-because he came up with the mechanism for how evolution happens -natural selection

Creationists! -believed in old testatment, god created species and are therefore perfect and unchanging -each organism had a purpose

-Aristotle believed in scala naturae -views species as fixed, and that life forms were on a scale of complexity like a ladder, unchanging -each scale is permanent

-Linnaeus classified organisms based on their similarities of look and purpose -he developed binomial naming in taxonomy (genus species) -the taxonomy system is nested. As you move out, there are less similar characteristics. The more specific, the more similar.

-fossils usually found in layers of strata, are glimpses of organisms past that were alive when the layer formed -younger stratum closer to the surface have more recent fossils and animals -shows that over time, similar yet different organisms existed

Father of palentology He said that catastrophes are the reason why the animals died. Boundary between strata represent catastrophes. -something must have wiped these live animals out in each layer!

-Lyell and Hutton were geologists who thought that changes in the Earth are from slow continuous actions -they are important because they moved AWAY from the creationists - earth ChangeS!! -Lyell - uniformitarianism - mechanisms of change are constant over time -influenced darwin 1) Earth DOES change! and 2) if uniformitarianism is true, and Earth changes slow but constantly, Earth is older than what they thought, and there must be similar biological patterns happening

-Darwin read Lyell's Principles of Geology wrote of uniformitarianism -Darwin then thought Earth must be older than 6000 years

-Lamarck also said Earth Changes! -Lamarch took a stab at trying to put a mechanism at how -Inheritance of aquired characteristics -it was unsupported

that if something because larger through use or was affected by use and disuse, that changed would be handed down to the next generation. -We now know changes on the body that are from use and disuse are not inherited

-Malthus said that in every generation more are born than survive, and that war, disease and famine kill them -In his theory, Darwin agreed with Malthus in the fact that organisms produce more organisms than the environment can support. He extrapolated further.

Descent with modification

-As a boy and into adulthood, Charles Darwin had a consuming interest in nature -Darwin first studied medicine (unsuccessfully), and then theology at Cambridge University -After graduating, he took an unpaid position as naturalist and companion to Captain Robert FitzRoy for a 5-year around the world voyage on the Beagle -During his travels on the Beagle, Darwin collected specimens of South American plants and animals -He observed that fossils resembled living species from the same region, and living species resembled other species from nearby regions -He experienced an earthquake in Chile and observed the uplift of rocks and saw strata

-Darwin had an interest in geographic distribution of species -He hypothesized that species from South America had colonized the Galápagos and speciated on the islands -This happened because the animals had to adapt to the new life (finches) -accumulation of adaptations to a different environment gave way to new species

formation of new species

inherited characteristics of organisms that enhance their survival and reproduction in a specific environment

-Over time, accumulation of adaptations to a different environment gave way to new species

Natural selection is a process in which individuals with favorable inherited traits are more likely to survive and reproduce (than other individuals because of those traits)

-Because of religion, persecuted, prosecuted, and also he thought he'd go to hell -hearing Russell Wallace pushed him to publish -over ten years, his ideas became generally accepted

today scientists use race to designate subspecies

-The unity of life - due to descent from common ancestor that lived in remote past. Per Darwin, history of life is like a tree with branches representing life's diversity. This meshed well with Linnaeus's hierarchy. -The diversity of life - adaptations of descendants caused diversity -The match between organisms and their environment

evolutionary history of a group

-species - made up of a group of populations over a geographic RANGE (many localities). These populations can reproduce with each other, although they may have different traits. -population is a subgroup of species and is local. It adapts to local conditions, but does not officially become a species unless it can no longer mate with other populations.

-Darwin noticed that for many years, humans have been selecting and breeding traits that they like in crops and animals -Today's stock animals and crops do not much resemble their wild ancestors because of artificial selection -Cross breeding brings out favorable traits -Nature must do something similar! per darwin

the mustard plant was artifically bred to produce brussels sprouts, kale, cabbage, broccoli

Obs 1: Members of a population often vary ( today we would say in their inherited traits- he did not know about genetics) Obs 2: All species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce (fungal spores, for example) (influenced by Malthus) Inf 1: Individuals that are well suited to their environment tend to leave more offspring than other individuals. Inf 2: Over time, favorable traits accumulate in the population.

Because those traits that allow them to live in their environment will be passed on to their progeny. Their offspring will therefore also have physical advantages that will allow them to survive in their environment (wont die off).

If some heritable traits are advantageous for survival in the current environment, these will accumulate in a population over time, and this will increase the frequency of individuals with these traits

-Individuals with certain heritable (we use this word today, Darwin didn't know about chromosomes or inheritance) characteristics survive and reproduce at a higher rate than other individuals -Natural selection increases the adaptation of organisms to their environment over time -If an environment changes over time, natural selection may result in adaptation to these new conditions and may give rise to new species (or to extinction)

No, only populations.

If trait is useful at a place in time, it may not be the case in the future. Things change. The environmental change is natural selection, and that which is advantageous may not be any more Species will adapt again and change over time.

-direct observation of evolutionary change , i.e. MRSA and evolution of drug resistant bacteria -Homology, anatomical or molecular that shows common ancestor in animals -Convergent Evolution - similar structures that develop in animals that are distant related but have adapted to the same environment -Fossil records that show transition animals

-Living things are changing in the world today, daily and can be observed. Natural selection edits or selects traits already present in population. -MRSA for example -SA had a variant existed that synthesized cell walls using a different protein, before methicillin every was used. -When methicillin was used, it became the natural selection event that killed the SA that didn't have the variant. -MRSA then propagated their resistantness over time since they were the ones that survived.

similarity resulting from a common ancestor, for example, homologous strucures like arms in humans, cats and whales -in comparative bio, anatomical structures are seen in embryos -vestigial structures -at the molecular level, genes shared among organisms inherited from a common ancestor

-Evolutionary trees are hypotheses about the relationships among different groups -Homologies form nested patterns in evolutionary trees -Evolutionary trees can be made using different types of data, for example, anatomical and DNA sequence data -branch points are a common ancestor for everything to the right of it -homologous characteristics are shared by all to the right of it also

-evolution of similar or analogous features in distantly related groups, in response to similar environments -Convergent evolution does not provide information about ancestry (phylogeny) -independent animals adapt in similar ways

-Convergent features share similar function, but not common ancestry. -homologous features have common ancestry but may have different functions.

The fossil record provides evidence of: - the extinction of species, - the origin of new groups, - changes within groups over time Fossils can document transitional animals.

-animals between ancestors and the animals of today -in fossils -can show how current animals transitioned from one phase of the earth to another, and from land to water, for example

-Biogeography, the geographic distribution of species, provides evidence of evolution -Earth's continents were formerly united in a single large continent called Pangaea, but have since separated by continental drift -This may explain why two islands with similar environments in different parts of the world will NOT be populated by the same species, even though their climates are the same. -instead, they will be populated by similar species of those found on the mainland nearest to island, even if environment is different.

-Not found anywhere else in the world -usually closely related to nearest mainland creatures

-Geological changes of the earth's surface helps us understand some elements of evolution -tectonic plates caused pangaea to break up

-though generally accepted, in science it is a theory, that is -a theory accounts for many observations and data and attempts to explain and integrate a great variety of phenomena -Ongoing research adds to our understanding of evolution -some parts were not true. For i.e. he said evolution is slow, but we now know that sometimes it can be quick.

Vestigial structures are remnants of features that served important functions in the organism's ancestors. For example whales have vestigial (internal) back leg bones

-At the molecular level, all organisms share the genetic structure of DNA and RNA -genetic code is also essentially universal

-pseudogenes - inactive genes that do not code for proteins

In the human genome and that of other families,1/2 of gene related DNA is solitary. Other half come in multigene families, or collections of two or more identical or very similar genes. Two types. Identical DNA sequences - clustered tandemly, and make RNAs Nonidentical genes are two related families of genes that make the alpha and beta globular proteins of hemoglobin. Sections of genes are expressed at different times in development, allowing hemoglobin to function effectively in the changing environment of the developing animal

Mutations are basis for change by: 1) Duplication of entire chromosome sets can cause an increase in genes. 2) Duplication and Divergence of portions of the chromosome

-Accident in meiosis can cause polyploidy - one or more extra sets of chromosomes. -Most often lethal, but sometimes not as long as one set of genes provides essential function. -The genes in the extra set of chromosomes can accumulate mutations, and these variations may be passed on to the future. -This way genes with new functions can evolve. In fact, around when dinosaurs died, duplications and inversions of large portions of chromosomes increased as a results of mistakes in meiosis. -This chromosomal rearranging is thought to have contributed to the generation of new speciesoffspring with duplicated/inverse DNA could not mate with others of the correct DNA results in two different species

-errors in meiosis can also lead to smaller regions of divergence in genes -Unequal crossing over in prophase 1 of meiosis can cause one chromosome to have a deletion and one to have two copies (never swapped!). -Template Slippage can occur -template shifts with respect to with respect to new complementary strand so part of template is skipped by replication machinery or used twice as a template. As a result, DNA is deleted or duplicated. -This could be how multigene families came to be.

Unequal crossing over in prophase 1 of meiosis can cause one chromosome to have a deletion and one to have two copies (never swapped!).

template shifts with respect to with respect to new complementary strand so part of template is skipped by replication machinery or used twice as a template. As a result, DNA is deleted or duplicated.

-From duplication error, to multigene families -Comparison of gene sequences can suggest order that genes arose -For example, the alpha and beta globin genes indicate that they all came from one common ancestral globin gene that underwent duplication and divergence differences from each of the globins came from mutations that arose over time when the gene was copied over many generations -Many mutations may have been bad or had no effect, but at least some mutations protein product was advantageous to the organism. -Natural selection acted on these genes, and these were the ones that propagated.

-Sometimes you have duplication that creates genes with totally new purposes. -Lysozymes for example are enzymes that hydrolyze bacterial walls. alpha lactalbumin is in mammal milk production. The two are similar in amino acid sequence and tertiary structure. However, there is a minor difference. Lysozyme is present only in birds. AT some point when mammals and birds separated, Lysozyme was duplicated in mammalian lineage, but not in birds. Then one copy of the Lysozyme gene developed into something totally different in mammals, while the other copy stayed as its original purpose.

-exons code for domain, a distinct structural or function region of protein -A particular exon of a gene could be duplicated in one and deleted from another -The one with two exons would code for a protein that has a second copy of the domain -This definitely changes structure, sometimes by augmenting it's function Sometimes exons mix and match (exon shuffling) -these new proteins with totally different domains can have new functions