P307 4. 10 year old. Better reproductive success. 5. a) protection from predators b) Reach or grab food c) Help to climb to avoid predators/get food d) Reproduction e) Speed f) Camo from predators 6. Always a work in progress. Always testing and building on.

p313 5. Duplications. 6. Dolphins thought to have evolved from land mammals.

Natural Selection

The Origin of Species On the Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life This is quite a title! But it does suggest that Natural Selection must play an important role in the creation of new species

But what is natural selection? Natural Selection is the way in which nature favours the reproductive success of some individuals within a population over others In other words, some individuals are more likely to pass their genes along than others

How Natural Selection Works Success can take many forms 1. Better suited to gathering resources in a population 2. Better able to avoid predators 3. Ability to adapt to a unique environment There is no single recipe for success

1. Gathering Resources Cheetahs A faster cheetah is more likely to catch its prey than a slower cheetah Faster cheetahs are more likely to eat regularly and stay alive So on average, faster cheetahs are more likely to reproduce and will have more offspring than slower cheetahs

1. Gathering Resources Darwin’s Finches Variation in the size and shape of beaks Each species has evolved to feed on unique things Differences in diet mean that they do not compete with each other for resources

1. Gathering Resources Anteaters Ant colonies can be large tunnel complexes Ancestors of anteaters with longer noses and tongues found it easier to eat ants directly out of the colony They were more likely to pass their genes and anteaters now have very long noses and tongues

Examples of Gathering Resources Ant Lion

Examples of Gathering Resources Honey Pot Ants

2. Avoiding Predators Camouflage The ability to blend in with surroundings provides an advantage in evading predators An insect that looks more like a leaf, for example, than another is more likely to be mistaken for a leaf and more likely to be ignored by a predator This camouflage is more likely to be passed along to future generations

Example of Camouflage Common Potoo

Common Potoo Video

2. Avoiding Predators Cactus Found mostly in dry, arid places Waxy coating helps keep water from evaporating Animals living in the desert eat plants for moisture Cacti have developed spikes to deter predators Since cacti with spikes are less likely to be eaten, they are also more likely to breed and pass on their genes

3. Adaptations to a Unique Environment A characteristic or feature of a species that makes it well suited for survival or reproductive success in its environment

3. Adaptations to a Unique Environment

3. Adaptations to a Unique Environment Fennec Fox Fennec foxes live in the desert Have large ears to dissipate heat Fennec foxes with large ears are less likely to over heat in the desert and are more likely to breed

3. Adaptation to a Unique Environment Remember the cactus, with its waxy coating? This coating prevents water evaporation in a hot, arid environment

3. Adaptation to a Unique Environment The polar bear Among the largest bears Has both a heavy double layer of fur and a layer of fat 4-5 inches thick, to survive extreme cold They are very strong swimmers Why might this be important?

3. Adaptation to a Unique Environment They are very strong swimmers Why might this be important? They live in oceanic areas and often live on areas of the sea frozen only during the winter months They blend well into their surroundings, making it harder for prey to spot them

Example of Adaptation to a Unique Environment Hydrothermal Vents in the Ocean

Predictions The Theory of Natural Selection allowed Darwin to make predictions he could not prove at the time (theory!) He predicted that, based on the location of great apes today, we would find fossil evidence of human ancestry in Africa (biogeography!)

Predictions Darwin’s orchid: flower with a very long spur He predicted an insect must exist with a very long proboscis, in order to pollinate it Madagascan Hawk Moth discovered in 1903

The Natural Selection Game Over the next several slides, you’ll see some species that in some way demonstrate natural selection Your job is to decide how that species has been affected by natural selection, or to decide which animal is most likely to pass it genes along

Giraffe

Roses

Walking Stick

The Cobra

Blue Shark

Venus Fly Trap

Octopus

Pangolin

Buckeye Butterfly

Angler Fish

Bee Orchid

Adaptation A characteristic or feature of a species that makes it well suited for survival or reproductive success in its environment Owl images

Adaptation Explains why the cactus can be successful in the desert

Survival of the Fittest This phrase has been used to describe Darwin’s theory Is this misleading?

Types of Selection Directional Selection Stabilizing Selection Disruptive Selection

Directional Selection Selection that favours an increase or decrease in the value of a trait from the current population average

Directional Selection Antibiotic Resistance in Bacteria

Stabilizing Selecton Selection against individuals exhibiting traits that deviate from the current population average

Stabilizing Selection Birth weight in human babies

Disruptive Selection Favours two or more variations of a trait that differ from the current population average

Disruptive Selection Rock Pocket Mouse

A Human Example Some populations have adapted to living at extreme heights Able to survive despite low oxygen levels

"The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick!” Darwin

Homework Questions PG. 335 #2, 6, 11 PG. 372 #17, 32