Chapter 4: Characteristics in Ecosystems Pages 84-131 Nelson
Section 4.1 • Recall: An environment includes biotic and abioticcomponents. • Interactions between organisms and their environment can be divided into four levels: individuals, populations, communities, and ecosystems.
Species:organisms that are able to breed with one another and produce fertile offspring. Population: a group of individuals of the same species living in a specific area
Community:all of the individuals in all of the interacting populations at a given time
Ecosystem: a community of populations together with the abiotic factors that surround and effect it.
ECOSYSTEM INTERACTIONS • ECOLOGY: the study of interactions between organisms and their biotic & abiotic environment • Recall examples of interactions: Biotic-Biotic: moose eating grass Abiotic-Biotic: sunlight on plants Abiotic-Abiotic: river eroding rocks
BIODIVERSITY WITHIN ECOSYSTEMS • ECOTONE: a transition areabetweenecosystems ecosystems don’t have sharp boundaries • organisms move back and forth from one ecosystem to another • therefore the ECOTONE between 2 ecosystems has greater biodiversity • see Fig. 1 p.87 • remember, areas with greater biodiversity are MORE STABLE
ROLES WITHIN ECOSYSTEMS • NICHE: an organism’s role in an ecosystem -its place in the food web -its habitat -its breeding area NOTE: each species in an ecosystem tends to have a different niche (read page 90) http://en.wikipedia.org/wiki/File:Dung_beetle_working-001.ogv
Niche • Helps us to understand how organisms in an ecosystem interact with each other. • The ecological niche of a population is the role that its members play in an ecosystem. Eg. Honeybees gather nectar from flowers to make honey - Pollinators
Community Ecology: Feel the Love - Crash Course Ecology #4 http://www.youtube.com/watch?v=GxE1SSqbSn4
COMPETITION FOR NICHES • if a new species enters an ecosystem (called an EXOTIC SPECIES), it often causes a disturbance • Why??? • it competes for a NICHE already occupied by a native species • it may have no natural predators • it may bring new disease that native species aren’t immune to • Read ‘Intro of exotic species’ p.91-92
Attack of the killer Cane Toads in Australia! • introduction of exotic species
Cane toad vs. fresh water crocodile … who wins? https://www.youtube.com/watch?v=w2bwUlu3eMc What is another example of an exotic species that was introduced in Australia? http://www.newscientist.com/article/dn14221-australian-crocs-hit-by-cane-toad-wave-of-death.html#.UiawBjasim4
Ahhh a cute bunny rabbit! European rabbits first arrived in Australia with the First Fleet in 1788, but they only became a pest after 24 wild rabbits were released for hunting near Geelong in Victoria 150 years ago. By the 1920s, Australia's rabbit population had swelled to 10 billion. So in 1950 the biological control agent, Myxoma virus, was introduced to Australia's mainland. To combat the reduced effectiveness of myxoma virus, calicivirus, or rabbit haemorrhagic disease (RHD), was released in Australia in 1995. http://www.abc.net.au/science/articles/2009/04/08/2538860.htm Are there examples of exotic species in Canada?
11 invasive species threatening Canadian habitats From parasites to crabs and living slime affectionately dubbed "rock snot," invasive species can wreak havoc when introduced into a new habitat. 1. Asian carp Source: http://www.cbc.ca/news/technology/story/2012/02/23/f-invasive-species.html
2. European green crab The European green crab preys on mussels, clams and other crabs, threatening shellfish stocks on the Atlantic coast. It's a naturally aggressive and territorial crab species, found near Prince Edward Island, Quebec's Magdalen Islands, Nova Scotia's Cape Breton Island and the waters off southern Newfoundland, where it was first discovered in 2007. According to Fisheries and Oceans Canada, unless controlled, the crab's impact will surely be felt in Newfoundland's ecosystem.
And then there is…#3-8 Zebra mussel Emerald ash borer Purple loosestrife Round goby Gypsy moth Sea lamprey
9. Didymo deserves it’s own page! (aka rock snot)
And…10-11 Gypsy moth Asian long-horned beetle his beetle from China attacks hardwood trees such as maples. It first appeared in North America in 1996 in New York state. In Canada, it was first found in 2003 in an industrial park between Toronto and the city of Vaughan. Larvae of the gypsy moth are known to eat the leaves of about 300 plants, causing widespread damage.
Task What outcomes have we covered so far?
Tasks • From Before • Page 75 Q’s 23-26 • Workbook from Unit A – due tomorrow BEFORE EXAM • EXAM TOMORROW • Unit B • 1. Case Study – page 88-89 – all q’s
Section 4.2 Terrestrial and Aquatic Ecosystems Nelson Pages 94-100
Curricular Outcomes: 20–B1.1k Define and explain the interrelationship among species, population, community and ecosystem 20–B1.2k Explain how a terrestrial and an aquatic ecosystem supports a diversity of organisms through a variety of habitats and niches
Curricular Outcomes: 20–B1.3k Identify biotic and abiotic characteristics and explain their influence in an aquatic and a terrestrial ecosystem in a local region 20–B1.4k Explain how limiting factors influence organism distribution and range
1. ABIOTIC FACTORS IN TERRESTRIAL ECOSYSTEMS • abiotic factors are the non-living components of an ecosystem • affect the type and number of organisms that can live there • Describe abiotic components that cause the two terrestrial ecosystems below?
Canadian Biomes – Page 94 Edmonton
TERRESTRIAL ECOSYSTEMS IN ALBERTA 1. TAIGA (BOREAL FOREST) ECOSYSTEMS • Northern & Central AB forests • Warm, wet summer; Cold, dry winter • Dominated by CONIFERS: • PINE trees, SPRUCE trees • cone-bearing trees that have needles -Reduce water loss ( S.A., thick cuticle) -Pyramid shape of tree heavy snow weight
Canopy (tree tops): find seed-eating birds, red & flying squirrels Forest Floor: find shade-loving plants (shrubs, ferns, mosses), moose, deer, bear, weasels, grouse, owls, etc. 2. MUSKEG ECOSYSTEM: More NorthernTaiga (colder!) PERMAFROSTbeneath soil (never melts!) Water never drains away…
Water soaks into the PEAT (decomposing organic matter) Forms the MUSKEG or BOG (swampy!) Very Acidic soil Find black spruce trees, mosses, lichens, caribou, mosquitoes! Very SLOW DECOMPOSITION Soil formation is very slow… damage to this ecosystem takes many years to repair…
BOG MUMMY A bog body is a human cadaver that has been naturally mummified within a peat bog.
3. GRASSLAND (“Prairies”) • Southern AB • Nutrient-rich black earth • Short-lived grasses provide large biomass for decomposition • More sunlight, less precipitation • limited diversity (no canopy, etc.) • Find “grasses and grazers” (various grass species, bison, deer) rabbits, gophers, hawks, grasshoppers, etc.
Rich, fertile soil (lots of “leaf litter”) • MOST DIVERSITY! • Canopy, understory, & forest floor • Bears, moose (“browsers”), deer, weasels, woodpeckers, shrubs, etc. etc. • See Fig 6 p.96 4. DECIDUOUS FOREST ECOSYSTEM Central AB Between grassland and taiga biomes Dominated by deciduous (leave-losing) trees aspen poplar, balsam poplar & birch
AQUATIC ECOSYSTEMS • Water covers 2/3 of earth • 97% is saltwater (oceans) • Evaporation from oceans = freshwater (most in form of snow & ice on earth) • ALBERTA aquatic ecosystems = ponds, rivers, and lakes
ALBERTA LAKE ECOSYSTEMS Sketch Fig 7 page 99
LITTORAL ZONE • extends from lakeshore to where plants are no longer rooted in the lake bottom • Shallow, lots of sunlight • Most productive part of lake - algae and plants performing photosynthesis • Plants can be floating (algae), emergent (water lilies) or submerged (seaweed)
LIMNETIC ZONE • Area of open water where there is still enough sunlight for photosynthesis • Plankton is food for consumers • AUTOTROPHIC PLANKTON (tiny plants & algae) • HETEROTROPHIC PLANKTON (tiny invertebrate animals)
PROFUNDAL ZONE • Deepest part of lake, no sunlight • not found in ponds or shallow lakes • Only nutrients = decaying matter (detritus) that falls from the limnetic zone • Find lots of decomposers (bacteria), few bottom-dwelling fish, & invertebrates • LOW O2 LEVELSdue to lack of plants and lots of decomposers
Wow, what at catch! Wow, um already then! FYI – Random fact of the day - GIANT CATFISH ARE “BOTTOM FEEDERS”
Section 4.3 Tasks • Read Pages 101-107 in your textbook • Complete Section 4.3 Questions – Page 107 - #’s 1-5, 7 • Make some notes on “Seasonal Variations in Canadian Lakes” – Nelson page 105-106 • No workbook for Chapter 4 – so all Q’s are hand-in
Homework Check • 1-5,7 on page 107 in due
This figure shows the change in populations of 2 populations of paramecia (single-celled organisms) placed in 3 different beakers. a) compare the growth of species 1 in Beaker A with the growth of species 2 in Beaker B b) What evidence suggests that the populations of paramecia affect each other? c) suggest a conclusion that can be drawn from the populations changes
4.4 Limits on populations and communities in ecosystems Pages 108-112
Biotic Potential (p108) • Field mice can reproduce every 6 weeks and can have litters of 6 or more. A population of 20 mice could become 5120 mice in six months! What factors prevent a population explosion of mice? • Biotic potential is the maximum number of offspring that a species could produce if resources are unlimited • Regulated by four factors: birth potential (max #/birth), capacity for survival (# reach reproductive age), breeding frequency, and length of reproductive life (age of sexual maturity and # of fertile years)
You afraid of a few mice? • http://www.youtube.com/watch?v=zWVw-j8eYSk
Limiting Factors and Carrying capacity • Recall that limiting factors are factors that restrict or limit the number and types of organisms able to survive in a particular environment • Limiting factors prevent populations from obtaining their biotic potential • The carrying capacity is the maximum number of individuals that can be supported by an ecosystem At what level do the deer reach their CARRYING CAPACITY?
ex. the small black spruce forest at Elk Island (the bog) can support 20 squirrels sketch growth curve here!
Factors Affecting Population Change:Density Dependent vs. density Independent Factors Density Dependent Density Independent • factors brought on by pop. size may limit further growth and / or reduce pop. #’s • May cause reduced birth rate and increased emigration • Biotic factors • When populations are small, density dependent factors do not limit growth • Examples include: disease, parasites, predation, starvation • any abiotic factorsthat will affect a pop., regardless of its size • Daily and seasonal temp. extremes • Natural disasters, including drought, floods, forest fires, etc.