Evolution and Community Ecology 5 CHAPTER Placeholder opening page, but maybe we can duplicate the look of the SE chapter opener page by using the same fonts and colors (and maybe that Ch 14 icon?)

Lesson 5.1 Evolution Scientists have identified and described over 1.5 million species. Millions more have yet to be discovered.

Genes Sequences of DNA codes for each particular trait Example: Blue eyes, tall, short

Evolution and Natural Selection Lesson 5.1 Evolution Evolution and Natural Selection Evolution-change of genes over time Gene pool: All the genes present in a population Biological evolution: change in a population’s gene pool over time A starting population of fish. Genes control the color and pattern of the fish’s scales.

4 Ways Evolution Occurs Mutation Migration Genetic Drift Natural Selection

Mutation Accidental change in DNA that can give rise to variation among individuals

Migration Movement of individuals into (immigration) or out of (emigration) a population Sometimes called “Gene Flow” Over generation, biological evolution occurs because the fish’s gene pool has changed.

Gene Flow (Migration)

Genetic Drift Evolution that occurs by chance Natural Disasters Run in with human nets, etc.

Natural Selection Process by which traits useful for survival and reproduction are passed on more frequently than those that are not Survival of the fittest: -high fitness produce more offspring & therefore pass on its genes more frequently than those with low fitness.

3 Conditions for Natural Selection Organisms produce more offspring than can survive. Nature has limitations (limiting factors) Struggle for survival

3 Conditions for Natural Selection (2) Individuals vary in characteristics, some of which are heritable Not every species is same Some fish are faster, darker, smaller Genes different Heritable Differences

3 Conditions for Natural Selection (3) Individuals vary in fitness, or reproductive success Survival of Fittest Fittest for its environment Adaptation: an inherited trait that increases an organisms chance of survival and reproduction.

http://www.youtube.com/watch?v=xkwRTIKXaxg Travel to Ecuador to see how the process of natural selection operates

Adaptations Desert plants have small or no leaves at all The insect that blends in and is able to survive may be more likely to reproduce.

White coat of polar bear helps in hunting Results of natural selection all around us NATURE SELECTS Adaptations Big ears of desert jack rabbit allow it to cool off quickly Long neck of giraffe allow it to reach food

Resistance Resistance: ability of one or more organisms to tolerate a chemical designed to kill it Able to survive & reproduce Pesticide resistance Antibiotic resistance

Impacts of Natural Selection: Resistance

Lesson 5.1 Evolution Artificial Selection Artificial selection: selection under human direction humans have chosen & bred animals & plants with beneficial traits. Image - http://www.flickr.com/photos/carolynconner/4264882098/ (Creative Commons licensed) Geyser info source - National Park Service: http://www.nps.gov/yell/planyourvisit/noldfaith.htm

Speciation: How did we get millions of species?

Speciation Process by which new species are generated Can occur in a number of different ways most important way is called: allopatric speciation– Geographic Isolation occur due to major rivers separating populations, lakes drying up and forming separate lakes, etc. resulted in every form of life on Earth— today and in the past

The canyon is a barrier to dispersal by small mammals, and as a consequence the isolated populations can diverge.

Extinction Extinction: disappearance of species from Earth Lesson 5.1 Evolution Extinction Extinction: disappearance of species from Earth occurs gradually, one species at a time, when environmental conditions change more rapidly than the species can adapt five known mass extinction events, each of which wiped out a large proportion of Earth’s species. Image - http://www.flickr.com/photos/carolynconner/4264882098/ (Creative Commons licensed) Geyser info source - National Park Service: http://www.nps.gov/yell/planyourvisit/noldfaith.htm Trilobites Marine arthropods that went extinct at the end of the Permian period. Did You Know? During the Permo-Triassic extinction 250 million years ago, 70% of all land species and 90% of all marine species went extinct.

Lesson 5.2 Species Interactions The zebra mussel has completely displaced 20 native mussel species in Lake St. Clair.

Lesson 5.2 Species Interactions The Niche Niche: describes an organism’s use of resources and functional role in a community. Affected by an organism’s tolerance Often restricted by competition Tolerance: ability to survive and reproduce under changing environmental conditions. Specialists: have restricted tolerance (ex: panda bears) Generalists: wide tolerance ranges (ex: rats)

Fundamental vs. Realized Niche Fundamental = Without competition Realized = With competition (restricted niche)

Competition Organisms compete when they seek the same limited resource. In rare cases, one species can entirely exclude another from using resources. To reduce competition, species often partition resources, which can lead to character displacement.

Lesson 5.2 Species Interactions Competition Intraspecific competition: competition among members of the same species Interspecific competition: competition among members of two or more different species Competitive exclusion: in rare cases, one species can entirely exclude another from using resources.

Resource Partitioning

Predation (+/-) The process by which a predator hunts, kills, and consumes prey Causes cycles in predatory and prey population sizes

Predator/Prey Cycles

Predation Defensive traits such as camouflage, mimicry, and warning coloration have evolved in response to predator-prey interactions.

Predation Some predator-prey relationships are examples of coevolution, the process by which two species evolve in response to changes in each other. Rough-Skinned Newt Did You Know? A single rough-skinned newt contains enough poison to kill 100 people. Unfortunately for the newt, its predator, the common garter snake, has coevolved resistance to the toxin.

Coevolution The Madagascar star orchid produces nectar at the bottom part of its slim, foot-long throat. After observing a specimen, Charles Darwin predicted the existence of a moth with a proboscis long enough to reach that nectar. Sure enough, decades later the giant hawk moth of Madagascar was discovered.

Parasitism and Herbivory (+/–) Parasitism: One organism (the parasite) relies on another (the host) for nourishment or for some other benefit Herbivory: An animal feeding on a plant

Parasitism and Herbivory (+/–)

Mutualism (+/+) and Commensalism (+/0) Mutualism: a relationship in which two or more species benefit Commensalism: a relationship in which one species benefits while the other is unaffected

Mutualism (+/+) and Commensalism (+/0) Clown Fish and Sea Anemones demonstrate mutualism because Anemones provide the Clown Fish with protection from predators while Clown fish defend the Anemones from Butterfly fish who like to eat Anemones.

Mutualism (+/+) and Commensalism (+/0) Barnacles adhering to the skin of a whale or shell of a mollusk

Lesson 5.3 Ecological Communities The sun provides the energy for almost all of the ecological communities and species interactions on Earth. Energy is not cycle but moves in a one-way stream used by each organism.

Primary Producers (Autotrophs) Lesson 5.3 Ecological Communities Primary Producers (Autotrophs) Capture energy from the sun or from chemicals and store it in the bonds of sugars, making it available to the rest of the community Energy from the sun is captured by plants, algae, or bacteria through photosynthesis. Energy from chemicals is captured by some bacteria through chemosynthesis. Did You Know? Deep-sea vents, far from sunlight, support entire communities of fish, clams, and other sea animals, which depend on energy converted through chemosynthesis.

Consumers (Heterotrophs) Lesson 5.3 Ecological Communities Consumers (Heterotrophs) Consumers: rely on other organisms for energy and nutrients Herbivores: plant-eaters Carnivores: animal-eaters Omnivores: plant and animal-eaters Detritivores and decomposers: recycle nutrients within the ecosystem by breaking down nonliving organic matter Cellular respiration: organisms use oxygen to break bonds in sugar and release its energy through (primary producers do this, too) California Condor Did You Know? Scavengers, such as vultures and condors, are just large detritivores.

Lesson 5.3 Ecological Communities Energy in Communities Trophic level: an organism’s rank in a feeding hierarchy Primary producers always occupy first trophic level of any community. only about 10% of the energy available at any trophic level is passed to the next; rest is lost to the environment as heat. Pyramid of Energy

Numbers and Biomass in Communities Lesson 5.3 Ecological Communities Numbers and Biomass in Communities A trophic level’s biomass is the mass of living tissue it contains. In general, there are more organisms and greater biomass at lower trophic levels than at higher ones.

A food chain is simple, direct, and linear A food chain is simple, direct, and linear. It is a single pathway of feeding relationships. Notice the direction the arrow points (); It points in the direction of the energy is being transfer, NOT “what ate what”. The arrow points to the organism that RECEIVES the energy.

Lesson 5.3 Ecological Communities Food Webs Food web: Shows the overlapping and interconnected food chains present in a community. This occurs because most organisms eat more than one organism and are consumed by more than one organism

Lesson 5.3 Ecological Communities Keystone Species Keystone species: species that have strong and/or wide-reaching effects on a community Removal of a keystone species can significantly alter the structure of a community.

Lesson 5.4 Community Stability A 2010 report on invasive species suggests that they cost the U.S. $120 billion a year in environmental losses and damages. Invasive kudzu

Ecological Disturbances Lesson 5.4 Community Stability Ecological Disturbances A community in equilibrium is generally stable and balanced, with most populations at or around carrying capacity. Disturbances or changes in the environment can throw a community into disequilibrium. Succession: community experiences predictable series of changes over time caused but severe disturbances. Forest fire

Lesson 5.4 Community Stability Primary Succession Primary succession: occurs when there are no traces of the original community remaining, including vegetation and soil, community is rebuilt from scratch Pioneer species: are the first to colonize. The environment changes as new species move in, adding nutrients and generating habitat.

Lesson 5.4 Community Stability Secondary Succession Secondary succession: occurs when a disturbance dramatically alters a community but does not completely destroy it Common after disturbances such as fire, logging, or farming Occurs significantly faster than primary succession

Lesson 5.4 Community Stability Succession in Water Primary aquatic succession occurs when an area fills with water for the first time. Disturbances such as floods or excess nutrient runoff can lead to secondary aquatic succession.

Lesson 5.4 Community Stability Climax Communities Ecologists once thought succession leads to stable “climax” communities. Climax communities: stable community that completes succession process Today, ecologists see communities as temporary, ever-changing associations of species. Communities are influenced by many factors and constant disturbances. Beech-maple forest, a classic “climax community”

Lesson 5.4 Community Stability Invasive Species Invasive species: nonnative organisms that spread widely in a community. Invasive species can be a community disturbance and a major problem in many parts of the world. Ex: zebra muscle A lack of limiting factors such as predators, parasites, or competitors enables their population to grow unchecked. Not all invasive species are harmful. Did You Know? Although the European honeybee is invasive to North America, it is beneficial because it pollinates our agricultural crops.