Discover Biology FIFTH EDITION 23 with parts of 21 & 22 Ecology in a nutshell 2012 W. W. Norton & Company, Inc. Ecology powerpoints Ecology: organisms and ecosystems biosphere all earths living organisms & their physical environments (living and non-living) Ecology - study of interactions between organisms and their environment biotic (living) and abiotic (nonliving) Example: Effect of Water Oceans, large lakes and mountains affect ecosystems Water gains and loses heat slowly mild climate lake effect Mountains often produce a rain shadow effect, in which little precipitation falls on the side of the mountain that faces away from the prevailing winds Rain Shadow: Same Island Biomes: regions of biosphere Biomes divided by climate and ecological features of each such region Terrestrial biomes - usually named after the dominant vegetation Aquatic biomes - classified by physical or chemical features e.g. salt content Introduced and invasive species Introduced species = in this location because of human activity invasive species = Any introduced species that becomes a major pest in a new environment Originally from Russia Brought over in ship ballast water Now quaaga muscles (worse) Zebra Mussels How Invasive Mussels Can Harm Whole Ecosystems invasive species = Any introduced species that becomes a major pest in a new environment zebra mussel outcompetes native mussels Eats all the algae: out of the Great Lakes and left little for other aquatic species to eat Threatens fishermen in Great Lakes Florida: Introduced & Invasives Introduced species = citrus trees invasive species = pythons iguanas monitor lizards snails Huge pythons eat EVERYTHINGamerica%E2%80%99s-most-unwanted-invasive-species/ Iguana in the toilet at Boca Grande! Giant lizards eat Cape Coral!! Giant Snails eat Florida houses!!! What Is a Population? population = all individuals of one species in an area Population size = # of individuals in population Population density = # of individuals per unit of area Exponential Growth what happens when there are no limits on resources Can not last for long in nature (always some kind of limiting factor) Logistic Growth & Limits Populations cannot increase in size indefinitely Some resource will become limited space nutrients habitat Logistic Growth: normal in nature Logistic growth = S-shaped curve resources become limited Logistic Growth: normal in nature carrying capacity = maximum population size in a given environment At the carrying capacity, the population growth rate is zero Population Crash: the unlucky option If you use up a resource too quickly, you may not slow down as you near carrying capacity Population Cycle population cycle = two or more species have populations change together (mutual influence) Hare predation affects lynx population Lynx (food) availability Affects lynx population Patterns of Population Growth Most populations have irregular fluctuations Populations of the same species may experience different patterns of growth What Does the Future Hold? Most research indicates that the current human impact on Earth is unsustainable Community: Not the mediocre sitcom community = several populations in same area grass, rabbit, deer, squirrel, oak tree Community Diversity Some communities have more diversity than others 2 parts to diversity: Species richness Relative species abundance Types of Species Interactions Everything in nature either makes its own food or eats something else for food Types of Consumers Herbivores: eat producers (plant/algae) Predators: eat prey (other animals) Omnivores: eat many things (plant or animal) Food Chain Apex Predator: top of food chain Usually a Tertiary or Quaternary consumer (Most ecosystems dont have enough energy to go higher) Trophic Levels and Energy Most organisms use around 10% of the energy they take in. Less food available at top Blue whale: biggest animal EVER Eats low on food chain: More food is available Food Chains vs. Food Web food chain simplified linear sequence A food web shows some of the complexity of the relationships in a community Organisms may eat an multiple trophic levels Relationships: Symbiosis Sym (same) + bio(life) = symbiosis When organisms live together. mutualism good for both commensalism good for one parasitism good for one, bad for one Relationships: Symbiosis Mutualism: both species benefits Relationships: Symbiosis Commensalism: one benefits, little effect on other Relationships: Symbiosis Parasitism: one benefits, the other is harmed nuisance: tapeworm in dog deadly: heartworm in dog host: what parasite feeds on It is often better to leave your host alive so you can continue to use them. Exception: you may need another host (T. gondii) Parasites can change behavior Toxoplasma gondii is a single-celled parasite, most often contracted from raw meat, that alters the brain activity of rodents How a Parasite Can Hijack Your Brain T. gondii improves its chances of spreading to cats by changing the behavior of infected rats Studies indicate T. gondii infections in humans also alter behavioralso more risky choices Relationships: Competition competition = two species in same place want same lifestyle/resource niche = resources and conditions needed for a lifestyle (job) Competitive exclusion = winning species stays. Looser moves away or dies out (looser is excluded from the niche) Competition (2 more ways) Interference = keep other species away from resource Try to use more of resource than other species Niche partitioning Reduce competition by using niche in different way. (loser finds a way to not be chased off) Consumers can cause natural selection Traits that help you not get eaten are passed on Induced defenses = plants attacked by herbivores (spines, chemicals) Other Defensive Adaptations Cryptic coloration & Camouflage Warning Coloration Mimicry Batsian Muellarian Cooperation Defensive Adaptations: camoflauge Trying not to be Seen by predators Defensive Adaptations: warning coloration Traits that help you not get eaten are passed on Warning coloration = youll regret it if you eat me or bother me Defensive Adaptations: Mimicry Mimicry = looking like something else Muellerian Mimicry = Member of group you should avoid Bastian Mimicry = Bluffing. Look like you are a member of a group to avoid Mullerian Mimicry: Member of group Insects with gang colors Black and yellow stripes mean leave me alone Shared warning coloration Batsian Mimicry: Bluffing When a defenseless organism tries to look like one to avoid Tetraponera twig ant (stinging) Ugandan jumping spider (tasty) Batsian Mimicry: Bluffing When a defenseless organism tries to look like one to avoid Batsian MimicWarning coloration Defensive Adaptations: cooperation Working together against predators Keystone Most important part of an arch Remove it an the arch falls down Small part, but ultra important for entire arch Keystone Species: big effects Keystone species = low numbers but have an important job in ecosystem Producer or consumer removing them from ecosystem causes a HUGE change Clicker Questions CHAPTER 23 Ecological Communities Concept Quiz Organisms that must survive by eating other organisms are called A. Producers B. Consumers C. Herbivores