Defensive Adaptations goal: don’t get eaten! Plants Grow thorns, spines, or rough leaves Produce secondary compounds that are bad-tasting, toxic or both Example: milkweeds produce cardiac glycosides that make herbivores sick if consumed. Primary compounds are those that ALL plants produce, which are carbs, lipids, DNA, etc.

Defensive Adaptations goal: don’t get eaten! Animals Also produce secondary compounds Hot quinones are sprayed on attackers by some beetles Bad smell in skunks

Defensive Adaptations goal: don’t get eaten! Animals Aposematic coloration: “warning coloration” A bright, easily remembered pattern lets your predators know you are dangerous so they won’t eat you! Ladybird beetles are bad, tasting so they’re red

Defensive Adaptations goal: don’t get eaten! Animals Coral snakes are poisonous so they’re banded with red, yellow, & black Poisonous butterflies (Monarch butterfly) have bright “warning” colors

Defensive Adaptations goal: don’t get eaten! Animals In general for animals, bright color = bad taste Works best on predators that can learn a toad that gets stung once by a bumblebee  won’t touch anything that resembles the bee for a long time If a jaybird eats a monarch, he vomits, then learns NOT to eat anything with the same color pattern

Defensive Adaptations goal: don’t get eaten! What are good “learning” predators… Ones that have a developed nervous system Developed nervous system = memory system Memory system allows organism to learn

Defensive Adaptations: Mimicry imitation for protection Batesian mimicry: one poisonous, one isn’t After a bird eats one monarch and gets sick, he will also avoid viceroys (even if they’re not poisonous)  non-poisonous imitator gains protection Top=monarch, bottom=viceroy (identified by black line running across the hind wings.

Defensive Adaptations: Mimicry imitation for protection Batesian mimicry: one poisonous, one isn’t Red and yellow kill a fellow, red and black venoms lack Coral Snake Scarlet King Snake "Red on yellow, kill a fellow "Red on black, friend of Jack“ "Red into black, venom lack; red into yellow, kill a fellow."

Defensive Adaptations: Mimicry imitation for protection Mullerian mimicry: both poisonous Reduces the total number of organisms that must be killed to “educate” the predator 3 or more species of toxic prey is better  mimicry ring Many poisonous butterflies of Heliconius look alike

Defensive Adaptations: Camouflage hiding from predators Opposite of aposematic coloration; makes organisms hard to see Disruptive coloration: breaks up the outline of an organism so it makes it hard to recognize

Offensive Adaptations goal: EAT so you can survive another day! How to get a meal Sit-and-wait predator: wait until the food comes to you Active searcher: go out and look for food Parasite: sit on your food all the time

Offensive Adaptations goal: EAT so you can survive another day! Sit-and-wait predator: wait until the food comes to you Camouflage and mimicry are common tactics The organism using these techniques do not get seen by potential predators AND Potential prey cannot see their predator Lunch!

Yellow Crab Spider captures small bee Birds can’t see it, and neither can the flies in which the spider feeds.

Competition Intraspecific competition: competition within the same species for the same resource (food/water, shelter/territory, mate, etc.)

Competition Intraspecific competition: competition within the same species for the same resource (food/water, shelter/territory, mate, etc.) Prevention: males & females may eat different foods OR the adult & young will eat different foods

Competition Interspecific competition: competition between different species for the same resource (food/water, shelter/territory, etc) May lead to extinction of one species by competitive exclusion By competing one gets forced out of their niche Niche Fundamental: like having your own room Realized: someone moving into your room

Organisms try to minimize competition Organisms try to minimize competition. Some kind of sharing or division of resources is better than fighting. When species live in close proximity to another or share the same resources they may form symbiotic relationships with one another We say that they live in niches (living conditions that are perfect for just those species)

Symbiosis When 2 or more species are in a close, long-term relationship 3 kinds: Mutualism Commensalism Parasitism

Mutualism (+/+) Both species benefit; win-win situation Example: oxpeckers feed on the ticks found on rhinos

Commensalism (+/0) One species benefits, the other doesn’t gain or lose anything from the relationship Example: remora fish and shark

Parasitism (+/-) One benefits, the other loses Example: Cat and tapeworm Types Ectoparasites: live outside the host like fleas & ticks Endoparasites: live within the host like viruses, bacteria, protozoans, etc.

Species can shape each other over time. Two or more species can evolve together through coevolution. evolutionary paths become connected species evolve in response to changes in each other

Coevolution can occur in beneficial relationships.

Coevolution can occur in competitive relationships, sometimes called evolutionary arms race.

How these organisms interact (symbiosis, predator-prey, competition, etc.) can affect how the population evolves. Natural selection can change the distribution of traits within a population

Natural selection acts on distributions of traits. A normal distribution graphs as a bell-shaped curve. highest frequency near mean value frequencies decrease toward each extreme value Traits not undergoing natural selection have a normal distribution.

Natural selection can change the distribution of a trait in one of three ways. Microevolution is evolution within a population. observable change in the allele frequencies can result from natural selection

Natural selection can take one of three paths. Directional selection favors phenotypes at one extreme.

Stabilizing selection favors the intermediate phenotype.

Disruptive selection favors both extreme phenotypes. Suppose there is a population of rabbits. The color of the rabbits is governed by two incompletely dominant traits: black fur represented by “B” and white fur represented by “b”. A rabbit with the genotype of “BB” would have a phenotype of black fur, a genotype of “Bb” would have gray fur (a display of both black and white) and a genotype of “bb” would have a phenotype of white fur. If this population of rabbits were put into an area that had very dark black rocks as well as very white colored stone, the rabbits with black fur would be able to hide from predators amongst the black rocks and the white furred rabbits would be able to hide in the white rocks, but the gray furred rabbits would stand out in both of the habitats and thus would not survive. Disruptive Selection is believed to be the driving force behind sympatric speciation.