Ecosystems & Communities Chapter 4 Ecosystems & Communities

Section 4-1: The Role of Climate Key Idea:. All organisms are adapted to live in a particular climate. This is done through years of evolution. What is the difference between weather & climate? Weather – the day-to-day condition of the Earth’s atmosphere at a particular time & place Climate – the average, year-after-year conditions of temperature & precipitation in a particular region - latitude & topography play a role Microclimate – conditions vary over small distances. South side of a rock is warmer than the north side.

Section 4-1: The Role of Climate What is the Greenhouse Effect? The atmosphere acts like a blanket because CO2 (carbon dioxide) , CH4 (methane), H2O vapor, etc. trap heat. This is a completely natural process that helps keeps the biosphere’s temperatures suitable for life. If it wasn’t for these gases, the Earth’s temperatures would be 30o C cooler.

Section 4-1: The Role of Climate What is the effect of latitude on climate? Latitudes farther away from the equator get less sunlight/heat. Key Idea: This unequal heating of the Earth creates ocean currents & prevailing wind patterns, both contribute to climate.

Section 4-1: The Role of Climate What are the 3 climate zones caused by latitude? Polar: A. Farthest from equator B. Gets the least amount of sun/heat due to low sun angle C. 66.5o to 90o latitude

Section 4-1: The Role of Climate What are the 3 climate zones caused by latitude? Temperate: A. Between the tropical & polar zones B. This zone has changes of seasons C. This is what we live in

Section 4-1: The Role of Climate What are the 3 climate zones caused by latitude? 3. Tropical: A. Nearest to & includes the equator B. Sun is mostly directly overhead all year long & no real change of season. C. 23.5o N = Tropic of Cancer 23.5o S = Tropic of Capricorn

Section 4-2: Niches & Community Interactions Key Idea: Ecosystems are shaped by biotic & abiotic factors. Biotic Factors: all of the living things that an organism can interact with like food chains and food webs Abiotic Factors: nonliving things that influence the interactions among organisms like climate/weather, soil type, and amount of water. Key Idea: The biotic & abiotic factors of the area in which an organism lives is called habitat.

Section 4-2: Niches & Community Interactions What is the relationship between habitat & niche? Tolerance – the range of environmental conditions an organism can survive. Habitat – “address” of the organism Niche – “job” of the organism Definition of Niche – full range of physical & biological conditions in which an organism lives & the way in which the organism uses those condition

Section 4-2: Niches & Community Interactions Three things you need to know about niches: The number of niches within an ecosystem is limited. No two species can occupy the same niche (a.k.a. – competitive exclusion principle) Evolution by natural selection determines which of the species get to occupy the niche.

Section 4-2: Niches & Community Interactions What is the difference between a fundamental niche & a realized niche? Fundamental niche – all of the possible niches that an organism can occupy Realized niche – the actual niche that the organism occupies due to competition

Section 4-2: Niches & Community Interactions Types of community interactions: Competition – organisms of the same or different species attempt to use the same resource (food, shelter, nesting site, etc.) Predation – one organism tries to capture & eat another organism Predator: the hunter Prey: the food organism * Predation is a key factor in evolution; cheetahs are fast because their prey is fast

Section 4-2: Niches & Community Interactions Types of community interactions: Herbivory – coevolution occurs between plants & herbivores. - grasses has evolved to grow from the bottom up to better survive getting eaten. - cactus has evolved spikes to keep from getting eaten.

Section 4-2: Niches & Community Interactions Types of community interactions: Symbiosis – a close, living arrangement between two different species in which at least one of them benefits. 3 Types of Symbiosis: 1. Mutualism – both species benefit A. Plants & their pollinators B. Humans & intestinal bacteria 2. Commensalism – one species benefits & the other is not affected A. Barnacles on whales B. Remoras that attach to sharks 3. Parasitism – one species benefits & the other is harmed A. Tapeworms, ticks, fleas, etc.

Section 4-3: Succession Ecological Succession: predictable changes in a community over time 3 Types of Succession: Primary Succession – occurs where there was no soil before (i.e. after a volcanic eruption or bare rock exposed by a melting glacier) Pioneer Species – 1st species to populate an area; often lichens (symbiotic relationship between an alga & a fungus) Secondary Succession – a disturbance has destroyed the existing community; occurs after a forest fire or after farmland has been abandoned. It should return to the original community known as the climax community. Marine Succession – occurs when a dead whale sinks to the deep bottom of the ocean