Evolution by Means of Natural Selection

Over a great period of time evolution can result in the formation of a new species. This is called? Speciation

Evolution only occurs when there is a change in ___________________________ within a population over time. GENE FREQUENCY 1st generation of Beetle population Many generations later of the same population

Mutation A change in a DNA sequence, usually occurring because of errors in replication or repair. This is the ultimate source of genetic variation.

Migration The chance of an individual moving to another population and sharing it’s genes there.

Genetic Drift The drift over time of allele frequencies in a population due to random sampling effects forming successive generations.

Natural Selection A process of evolution in which traits that result in better fitness of an individual survives to the next generation.

"One obstacle to understanding evolution is the common misconception that individual organisms evolve. It is the population, not its individuals, that evolves, as some heritable variation becomes more common at the expense of others."

What influenced Darwin to develop the theory of evolution? Fossil Record Fossil Record Geographic Distribution Embryology Homologous Structures Vestigial Structures Artificial Selection

What Do Modern Scientists use as evidence of evolution? Similar Biochemistry DNA ATP Hormones

Example: Large Scale: Cell phones over the last 20 years Example: Large Scale: Cell phones over the last 20 years. Think of the starting phone as the car phone, then every new phone that led to the I-phone is a new generation (All different brands/species, to make the best phone). Small Scale: Updates from phone to phone: antenna, screen size, touch screen, ect.

See how mario, link, and donkey kong have evolved See how mario, link, and donkey kong have evolved. At first they started out as blocky objects and now they look more and more real.

differential reproduction and survival of individuals in a population Natural Selection DNA genotype RNA Protein Phenotype differential reproduction and survival of individuals in a population changes in anatomy physiology, and/or behavior The Modern Understanding of Darwin’s Principles

Adaptations Hereditary characteristic that helps an organism survive and reproduce under a certain set of environmental conditions. Example: color patterns can be advantageous to an animal, making it inconspicuous to its predators

The Co-evolution of Predator and Prey Consumption of one species (the prey) by another (the predator) Natural selection shapes the body forms and behaviors of both predator and prey

Natural Selection, Predators, and Prey Prey that can survive attacks from predators will reproduce and pass those traits down to their offspring. Predator that can beat the competition for food will survive and reproduce, passing on their traits to their offspring

The predators with the best “hunting equipment” will survive and reproduce, passing on their good hunting traits

Acute Senses

The prey with the best way of avoiding predators will survive and reproduce, passing their traits to the next generation. Predator and prey both evolve more efficient ways to interact. They adapt to each other.

Mimicry - the ability of some creatures to imitate others, either by sound or appearance for protective purposes

Camouflage - Protective coloring or another feature that conceals an animal and enables it to blend into its surroundings.

Chameleon Chameleon

Stick Bug

Warning Coloration Conspicuously recognizable markings of an animal that serve to warn potential predators of the nuisance or harm that would come from attacking or eating it. The bold patterns of skunks and the bright colors of poison arrow frogs are examples of warning coloration.

The Role of the Environment When the environment changes, organisms are forced to adapt. Hereditary characteristics help organisms survive and reproduce under a certain set of environmental conditions. What are some examples of big environmental changes?

What Limits a Population?

Carrying Capacity – the number of individuals that an environment can support Affected by predator prey relationships and the environment

Competition- When two or more organisms go after the same limited resources In an environment resources that support a population are limited. There is only so much food, space, water, and other essentials available to support the population We call these resources that support a population but have the chance of running out, LIMITED RESOURCES

SURVIVAL OF THE FITTEST! Natural Selection When populations grow, competition increases, as limited resources decrease. Only those with better adaptations will survive, and the weak will struggle. SURVIVAL OF THE FITTEST! Natural Selection

Bear and Salmon

A = lag phase (very few organisms to begin with – reproduction is slow B = acceleration phase C = exponential phase F = population crash due to limited resources

Predator Prey Relationships Balance Populations Predator Prey relations are important to balance an ecosystem’s populations. If prey populations increase what will happen to the predator population? It will increase due to the larger amounts of food available.

You can see an obvious cycle, prey numbers go up followed by predator numbers going up, then prey drops, predators drop

If the deer population became out of control in Effingham, what could be done to control or balance the population?