Survival of the Fittest Adaptation, Mutation, and Finches?

Natural Selection Natural selection means that traits that offer an advantage will most likely be passed on to offspring; individuals with those traits have a better chance of surviving.

Lemurs of Madagascar

Amazonian Frogs

Humans select traits for dogs, pigeons and other animals when they breed them. Bred Pigeons came from a single original species Who selects the traits for wild plans & animals?

Survival of the Fittest NOBODY!! There is no agent involved in natural selection. Natural selection is a process of elimination INDIVIDUALS THAT HAVE TRAITS THAT ARE BEST ADAPTED FOR THE CURRENT ENVIRONMENT ARE THE ONES THAT SURVIVE TO BREED AND PASS ON THEIR GENES TO THE NEXT GENERATION. Organisms not possessing the beneficial traits either die or don’t have as many offspring. Natural Selection is Survival of the Fittest

Survival of the fittest? The individuals that survive are not always the strongest, fastest, or smartest. Therefore, "survival of the fittest" may not be the best way to describe what natural selection really is as it applies to evolution. Darwin meant "fittest" to mean the one best suited for the immediate environment. This is the basis of the idea of natural selection. The individual of the population only needs to have the most favorable traits to survive in the environment. It should follow that individuals who have the favorable adaptations will live long enough to pass down those genes to their offspring. Individuals lacking the favorable traits, in other words the "unfit", will most likely not live long enough to pass down the unfavorable traits and eventually those traits will be bred out of the population. The unfavorable traits may take many generations to decline in numbers and even longer to disappear completely from the gene pool. This is evident in humans with the genes of fatal diseases are still in the gene pool even though they are unfavorable for the survival of the species.

Natural Selection is a mixture of both Chance and necessity Natural Selection is not goal directed. It does not have a long term goal.

What are pressures that act on a population? Competition for food Competition for a mate Changes in the environment Predators Parasites

Examples of selection pressures... Predators - variants with adaptations allowing them to escape predators have more offspring e.g. speed, defensive weapons, camouflage, mimicry Prey/Food - variants with adaptations allowing them to obtain food have more offspring e.g. Speed, senses for finding prey/food, weapons for killing prey or obtaining food, camouflage for stealth Climate - those who can survive new climate best have more kids e.g. ice age, change in climate due to migration. Mates - variants with adaptations allowing them to attract a mate to have offspring - e.g. strong, attractive, good provider

Mechanism for change in a population of organisms Animals who have greater fitness survive in environment and live to reproduce Random changes (mutations) can lead to greater or less fitness Adaptations allow an organism to survive better in their environment

Natural Selection vs. Selective Breeding Process by which organisms that are most suited to their environment survive and reproduce most successfully. Method of breeding that allows only those organisms with desired characteristics to produce the next generation.

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Let’s Review Do you remember these guys?

The adaptation of a population in response to pollution. “Industrial Melanism”- darkness- of the skin, feathers, or fur. Acquired by a population of animals living in an industrial region where the environment is soot-darkened.

Example: Peppered Moths Manchester, England from 1845 to 1890. Before the industrial revolution, the trunks of the trees in the forest around Manchester were light grayish-green due to the presence of lichens.

Most of the peppered moths in the area were light colored with dark spots. As the industrial revolution progressed, the tree trunks became covered with soot and turned dark. Over a period of 45 years, the dark variety of the peppered moth became more common.

Can you see the moths?

Natural Selection Mouth parts External color Behavior ex: beaks, teeth Summary: Environmental Influence due to organism adaptation. Mouth parts ex: beaks, teeth External color ex: fur, scales, feathers Behavior

Galapagos Islands 1850’s: Charles Darwin described how organisms might change over time. Theory of Evolution 5 years of observations on the islands.

The Galapagos Island The smallest, lowest islands were hot, dry, and nearly barren-Hood Island-sparse vegetation The higher islands had greater rainfall and a different assortment of plants and animals-Isabela- Island had rich vegetation.

Galapagos Finches

The Galapagos Island Darwin was fascinated in particular by the land tortoises and marine iguanas in the Galápagos. Giant tortoises varied in predictable ways from one island to another. The shape of a tortoise's shell could be used to identify which island a particular tortoise inhabited.

Animals found in the Galapagos Land Tortoises Darwin Finches Blue-Footed Booby Marine Iguanas

Animals

The Journey Home Darwin Observed that characteristics of many plants and animals vary greatly among the islands Hypothesis: Separate species may have arose from an original ancestor

Selective breeding Domestic Animals Plants: Summary: Human Influence on characteristics and behavior. Domestic Animals Ex: Chickens, Dogs, Cows Plants: Ex: Corn, Brasilica, Fruit hybrids

Domestic Animals Various animals that have been tamed and made fit for a human environment.

Boxer Pug Bull Terrier Basset Hound A shorter face means a host of problems. The modern Boxer not only has a shorter face but the muzzle is slightly upturned. The boxer – like all bracecyphalic dogs – has difficulty controlling its temperature in hot weather, the inability to shed heat places limits on physical performance. It also has one of the highest cancer rates. Pug The Pug is another extreme brachycephalic breed and it has all the problems associated with that trait – high blood pressure, heart problems, low oxygenation, difficulty breathing, tendency to overheat, dentition problems, and skin fold dermatitis. The highly desirable double-curl tail is actually a genetic defect, in more serious forms it leads to paralysis. Basset Hound

How many types of apples are there? Hybrid Fruits Nectarcots Pluots How many types of apples are there?