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EVOLUTION & SPECIATION Mr.Nichols PHHS. QUIZ TIME!!!!. 1.) What is evolution and how does it explain natural selection? 2.) How can gene flow give a population an overall greater fitness? 3.) Why do small populations evolve faster? Provide an allele example.
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QUIZ TIME!!!! • 1.) What is evolution and how does it explain natural selection? • 2.) How can gene flow give a population an overall greater fitness? • 3.) Why do small populations evolve faster? Provide an allele example. • 4.) Why are hybrids not considered their own species? • 5.) How does unnatural selection lead to declines in genetic diversity? Why is that bad?
Breaking News! • Sonya Prior ran away from home yesterday evening after dinner. • Police have been searching for her and have been unsuccessful. • CONFIDENTIAL: Sonya takes medication for a rare heart condition, if she does not take her medication every 18 hours she’s in serious danger. • WE MUST FIND HER!!!!!!
Founder Effect: a cause of genetic drift attributable to colonization by a limited number of individuals from a parent population
Gene Flow: genetic exchange due to the migration of fertile individuals or gametes between populations (reduces differences between populations)
Nonrandom mating: inbreeding and assortive mating (both shift frequencies of different genotypes)
Sexual selection • Sexual dimorphism: Gender phenotypic differences in a species. • Sexual selection: selection towards sex characteristics that leads to sexual dimorphism
Natural Selection on Polygenic Traits • Shifts to middle range • Shifts to 2 extremes • Shifts to 1 extreme
SPECIATION • THE FORMATION OF NEW SPECIES • AS NEW SPECIES EVOLVE, POPULATIONS BECOME REPRODUCTIVELY ISOLATED • REPRODUCTIVE ISOLATION – MEMBERS OF 2 POPULATIONS CANNOT INTERBREED & PRODUCE FERTILE OFFSPRING.
3 ISOLATING MECHANISMS…….. • BEHAVIORAL ISOLATION- CAPABLE OF BREEDING BUT HAVE DIFFERENCES IN COURTSHIP RITUALS (EX. MEADOWLARKS) • GEOGRAPHICAL ISOLATION – SEPARATED BY GEOGRAPHIC BARRIERS LIKE RIVERS, MOUNTAINS, OR BODIES OF WATER (EX. SQUIRREL) • TEMPORAL ISOLATION – 2 OR MORE SPECIES REPRODUCE AT DIFFERENT TIMES.
Tigon Result of male tiger and female lion mating incaptivity. Offspring are infertile. Separated both geographically and ecologically.
Liger Result of male lion and female tiger mating in captivity. Offspring are infertile.
Fig. 23.6 Four species of leopard frogs: differ in their mating calls. Hybrids are inviable.
These squirrels live on opposite sides of the Grand Canyon. This is an example of allopatric speciation.
Hawaiian Honeycreepers An example of adaptive radiation – these species all diverged from a common ancestor (founder species) FOUNDER SPECIES
Evidence of Evolution • Fossil Record • Geographic Distribution of Living Species • Homologous Body structures • Similarities in Embryology
Evidence of Evolution Fossil Record provides evidence that living things have evolved Fossils show the history of life on earth and how different groups of organisms have changed over time
Organism of the Day 1 North American Destroying Angel: Amanita bisporigera Kingdom: FungiPhylum: BasidiomycotaClass: AgaricomycetesOrder: AgaricalesFamily: AmanitaceaeGenus: AmanitaSpecies: Amanita bisporigera
‘Fun’gi Facts…..lol • It is commonly known as the North American destroying angel or the destroying angel. Amanita bisporigera is considered the most toxic North American Amanita mushroom, with little variation in toxin content between different fruit bodies. • This causes cellular necrosis, especially in cells which are initially exposed and have rapid rates of protein synthesis. This process results in severe acute liver dysfunction and, ultimately, liver failure. Amatoxins are not broken down by boiling, freezing, or drying.
More ‘Fun’gi Facts • The first reported poisonings resulting in death from the consumption of A. bisporigera were from near San Antonio, Mexico in 1957, where a rancher, his wife, and three children consumed the fungus; only the man survived. • Amanita poisoning is characterized by the following distinct stages: The incubation stage is an asymptomatic period which ranges from 6 to 12 hours after ingestion. In the gastrointestinal stage, about 6 to 16 hours after ingestion, there is onset of abdominal pain, explosive vomiting, and diarrhea for up to 24 hours, which may lead to dehydration, severe electrolyte imbalances, and shock. In the cytotoxic stage, 24 to 48 hours after ingestion, clinical and biochemical signs of liver damage are observed, but the patient is typically free of gastrointestinal symptoms. The signs of liver dysfunction such as jaundice, hypoglycemia, acidosis, and hemorrhage appear.
Fungi and Pictures • Like most other Amanita species, A. bisporigera is thought to form mycorrhizal relationships with trees. This is a mutually beneficial relationship where the hyphae of the fungus grow around the roots of trees, enabling the fungus to receive moisture, protection and nutritive byproducts of the tree, and giving the tree greater access to soil nutrients
Organism of the Day! • Yeti Crab: Kiwahirsuta • Kingdom: Animalia • Phylum: Arthropoda • Subphylum: Crustacea • Class: Malacostraca • Order: Decapoda • Infraorder: Anomura • Family: Kiwaidae • Genus: Kiwa • Species: K. hirsuta
Yeti Crab Fun Facts • The animal has strongly reduced eyes that lack pigment, and is thought to be blind. The "hairy" pincers contain filamentous bacteria, which the creature may use to detoxify poisonous minerals from the water emitted by the hydrothermal vents where it lives. Alternatively, it may feed on bacteria, although it is generally thought to be a carnivore. • Kiwa hirsuta is a squat lobster, more closely related to crabs and hermit crabs than true lobsters. • Most of the crabs were living at depths of about 2,200 meters (7,200 feet) on recent lava flows and areas where warm water was seeping out of the sea floor. • Discovered in March 2005.
Organism of the Day! • Emperor Penguin:AptenodytesForsteri • Kingdom: AnimaliaPhylum: ChordataClass: AvesOrder: SphenisciformesFamily: SpheniscidaeGenus: AptenodytesSpecies: A. forsteri
Emperor Penguin Fun Facts • The Emperor Penguin (Aptenodytesforsteri) is the tallest and heaviest of all living penguin species and is endemic to Antarctica. The male and female are similar in plumage and size, reaching 48 inches in height and weighing anywhere from 49 to 99 pounds. • The only penguin species that breeds during the Antarctic winter, it treks 31–75 mi over the ice to breeding colonies which may include thousands of individuals. The female lays a single egg, which is incubated by the male while the female returns to the sea to feed; parents subsequently take turns foraging at sea and caring for their chick in the colony. The lifespan is typically 20 years in the wild, although observations suggest that some individuals may live to 50 years of age.
More Fun Facts The Emperor Penguin breeds in the coldest environment of any bird species; air temperatures may reach −40 °F, and wind speeds may reach 89 mph. Water temperature is a frigid 28.8 °F, which is much lower than the Emperor Penguin's average body temperature of 102 °F. The species has adapted in several ways to counteract heat loss. Feathers provide 80–90% of its insulation, and it has a layer of sub dermal fat which may be up to 3 cm (1.2 in) thick before breeding. • While diving, the Emperor Penguin's oxygen use is markedly reduced, as its heart rate is reduced to as low as 15-20 beats per minute and non-essential organs are shut down, thus facilitating longer dives.
Fun Facts Plus Pictures • Emperor Penguins are serially monogamous. They have only one mate each year, and stay faithful to that mate. However, fidelity between years is only about 15%. After laying, the mother's nutritional reserves are exhausted and she very carefully transfers the egg to the male, before immediately returning to the sea for two months to feed. The transfer of the egg can be awkward and difficult, and many couples drop the egg in the process. When this happens, the chick inside is quickly lost, as the egg cannot withstand the freezing temperatures on the icy ground.
NEW VOCABULARY • POPULATION – GROUP OF INDIVIDUALS OF SAME SPECIES THAT INTERBREED • GENE POOL –ALL GENES PRESENT IN A POPULATION • NATURAL SELECTION - INDIVIDUALS BETTER ADAPTED TO THE ENVIRONMENT ARE ABLE TO SURVIVE & REPRODUCE. • A.K.A. “SURVIVAL OF THE FITTEST”
Gene Pool Combined genetic info. of all members Allele frequency is # of times alleles occur