PACKET 9: Evolution

Evolution Survey According to evolution, people came from monkeys a long time ago. Evolution was first proposed and explained by Charles Darwin. Evolution is also known as natural selection. Evolution is only something that happened in the past; it is not happening now. Evolution is something that happens to individual organisms. There is actually very little evidence for evolution. Evolution has been tested and challenged many times but has been supported by the results. Evolution involves individuals changing in order to adapt to their environments.

How did we go from simple single-celled organisms to the diversity of life we see today? A review of experiments: Abiogenesis vs. biogenisis _________________________________ or spontaneous generation – early theory that life came from non-life Ex: food left out (non-life) had maggots (life) crawling in it a few days later. ________________________________ – life from preexisting life How did the maggots really end up on the food? ABIOGENESIS BIOGENESIS FLIES LAYING EGGS ON THE FOOD AND THE EGGS HATCH.

Miller & Urey Experiment Miller & Urey conducted an experiment. Describe the purpose of this experiment. show how organic compounds were formed from inorganic compounds. They found a.a. (amino acids) which are organic. Important b/c amino acids make proteins which are needed for life.

Endosymbiosis Theory Explain the Endosymbiosis Theory. Eukaryotic cells were formed when smaller prokaryotes moved inside larger prokaryotes and they formed a relationship. Shows evolution of more complex cells.

The Evolution of a Cell (Simple to Complex) Evolution of Life - the order of their suspected appearance on Earth)he first life forms: Were they? Circle one of the pairs of terms below Explanation or What chemical process occurred that allowed there to be aerobic organisms? SIMPLEST CELL – NO NUCLEUS prokaryotic eukaryotic HETEROTROPHS JUST EAT FOOD, THEY DON’T ACTUALLY MAKE IT autotrophic heterotrophic Aerobic (used oxygen) THERE WASN’T ANY OXYGEN ON EARLY EARTH Anaerobic (didn’t use oxygen) PHOTOSYNTHESIS BECAUSE IT RELEASES OXYGEN Based on the info from the table – list the order of organisms as they appeared on Earth. ANAEROBIC, HETEROTROPHIC PROKARYOTES ANAEROBIC, AUTOTROPHIC PROKARYOTES AEROBIC PROKARYOTES EUKARYOTES

How did we go from simple single-celled organisms to the diversity of life we see today? Picture Terms Define anaerobic prokaryotes (heterotrophs) photosynthetic prokaryotes (autotrophs) Cells that don’t need oxygen Cells without a nucleus Obtain energy by “eating” Use light to make food Cells without a nucleus Make own food

unicellular eukaryotes Picture Terms Define aerobic prokaryotes unicellular eukaryotes multicellular eukaryotes Cells that need oxygen Cells without a nucleus One cell Cells with a nucleus Many cells Cells with a nucleus

Early Earth – Place the following items in correct order 1 _______Earth is formed with toxic gases, water vapor, and no oxygen _______Eukaryotic cells (more complex cells with a nucleus) form through endosymbiosis _______Earth’s surface cools and water vapor forms oceans as it rains _______Simple organic molecules such as amino acids and carbohydrates form from the thunderstorms _______Protocells (non-living groups of molecules) form and contain RNA _______Photosynthetic prokaryotes form adding oxygen to the atmosphere _______Ozone (O3) layer forms from atmospheric oxygen to protect Earth _______Multicellular eukaryotes form _______Prokaryotic cells form. Prokaryotes are simple cells that include bacteria. 8 2 3 4 6 7 9 5

Theories of Evolution (Lamark versus Darwin) In its most basic terms, the theory of evolution states that species _____________ over time. Lamark – Use Disuse Hypothesis or Passing on of Acquired Characteristics CHANGE

Lamark – Use Disuse Hypothesis or Passing on of Acquired Characteristics Summarize how Lamark believes the giraffe got its long neck. What is wrong with the inheritance of acquired traits hypothesis? At first all giraffes had short necks. In order to reach the leaves in the trees the giraffe stretched its neck. All of this stretching actually lengthened the giraffes neck. This was passed onto the offspring and the next generation had longer necks. This kept happening and that is how we have the long neck giraffe today. Parents pass DNA (genes) to their kids, not characteristics they obtain during their lifetime.

Darwin – Theory of Evolution by Natural Selection ___________ ____________ - Organisms with useful traits survive, reproduce, and pass those traits to their offspring.

Darwin – Theory of Evolution by Natural Selection Summarize how Darwin believes the giraffe got its long neck. Giraffes had different length necks to begin with. Those with the longer necks had an advantage and reached the leaves in the trees. These giraffes survived and reproduced and passed the gene for a long neck onto their offspring. SURVIVAL of the FITTEST Darwin described this as _______________________________. The term fitness in an evolutionary sense is a measure of an individual’s ability to survive and reproduce more offspring that can in turn survive and to reproduce.

Cause & Effect Model for Evolution by Natural Selection:   *** ___________ mutate  ________________ are selected  ______________ evolve*** GENES INDIVIDUALS POPULATIONS

Microevolution GENE POOL small genetic changes in the gene pool of a population _______________– all the alleles in a population (look at the # of B’s vs. the # of b’s) GENE POOL

3 TYPES OF NATURAL SELECTION MICROEVOLUTION DIRECTIONAL SELECTION – “it pays to be different” – individuals with traits at one end are more common than midrange forms Ex: peppered moths STABILIZING SELECTION – “it pays to be average” – eliminates individuals on both ends of the range and favors midrange individuals Ex: birth weights DISRUPTIVE OR DIVERSIFYING SELECTION – both ends of the range are favored and those in the middle are reduced. Ex: finch beaks

Changing Environments Select for Specific Genetic Phenotypes Before the Industrial Revolution the trunks of certain trees were a light color. The lighter peppered moths had an advantage over the darker moths. The lighter moths were more likely to survive and reproduce so there were more of them in the population. However, with the Industrial Revolution came pollution. The trees turned dark. Now the darker moths had the advantage. Adaptations are dependent upon the environment.

Macroevolution - How new species are formed – changes in a species so a new species is formed _________________________________ can lead to the formation of New Species Sometimes organisms of the same species become physically separated. The evolution of separate species is largely due to genetic drift (chance). After a long period of time even if the two groups were to meet back up the organisms may refuse to mate. At this point they would be considered separate species. When one species becomes 2 separate species this is called GEOGRAPHICAL ISOLATION SPECIATION

Types of Evolution COEVOLUTION ADAPTIVE RADIATION ____________________________ – changes in genetic composition of one species in response to change in another Ex: flowers & pollinators   ___________________________ - the changing of organisms to fit new environments. ADAPTIVE RADIATION

DIVERGENT VS. CONVERGENT EVOLUTION DIVERGENT EVOLUTION _______________________ - accumulation of differences between groups which can lead to the formation of new species CONVERGENT EVOLUTION  __________________________ - organisms that are not closely related evolve similar traits due to living in similar environments. .

Genetic Drift Genetic drift ___________________________ - random changes in alleles of a gene pool due to chance. Affects smaller populations more. Genetic drift

2 Models of Evolution Gradualism Punctuated equilibrium ________________ - gradual change over time leads to species formation Gradualism _________________________– evolution occurs in spurts in which there are periods of rapid change in a species followed by periods of little or no change (usually do to major environmental changes) Punctuated equilibrium

Evolution of Antibiotic Resistance: Antibiotics used only when needed and as directed usually overwhelm the bacteria. Too much antibiotic use selects for more resistant mutants. When patients cut short the full course of drugs, the resistant strains have a chance to multiply and spread.

Evidence For Evolution: 1. Fossil Evidence Fossils show patterns of development _____________________________– fossils found deeper down in the strata (rock layers) are older than those found closer to the top. LAW OF SUPERPOSITION

The fossil record shows transitional forms of organisms.

Evidence For Evolution: Anatomical structures ____________________________________ – structures that are present in an organism but reduced in size or have less important function (Ex: wings in flightless birds, hind limbs in whales) ____________________________________ – structures that share a common ancestry (similar structure but different functions) Ex: human arm, bat wing, whales flipper VESTIGIAL STRUCTURES HOMOLOGOUS STRUCTURES

HOMOLOGOUS STRUCTURES

Evidence For Evolution 3. Molecular Evidence for Evolution If species change over time then genes have also changed (DNA fingerprinting) _______________________– a species from which 2 or more species have diverged Scientists look at _______ and _________________. The more similar the DNA or protein sequence, between 2 different organisms, the more recently they shared a common ancestor. COMMON ANCESTOR DNA PROTEINS

EVOLUTIONARY RELATIONSHIPS _________________ & _________________________ – show how organisms are related through evolution CLADOGRAMS PHYLOGENETIC TREES

In the cladogram below, the greater the evolutionary distance from humans, the greater the number of amino acid differences in the hemoglobin protein (polypeptide).

EMBRYONIC ___________________ development shows common ancestry – similarities in early development show similar genes are at work