Bio 200 Week 12 & 13 Lecture Notes
Bio 200 Week 12 & 13 Lecture Notes BIO 200LLB
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This 5 page Class Notes was uploaded by Nicole on Wednesday November 25, 2015. The Class Notes belongs to BIO 200LLB at University at Buffalo taught by Lindqvist, C in Fall 2015. Since its upload, it has received 26 views. For similar materials see Evolutionary Biology in Biological Sciences at University at Buffalo.
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Date Created: 11/25/15
November 18 2015 Lecture 25 Ecology the study of distribution and abundance Evolution and ecology are intimately connected Competition for food mates and changes in songs are all examples of things that can affect evolutionary forces Ecologists spend a great deal of time forecasting evolution There are Two Parts of the Environment 1 Abiotic Nonliving Factors 2 Biotic Living Factors Abiotic Climate is controlled by 3 factors 1 Variation in light intensity a b c Light hits the equator more directly than either of the poles This causes dry and wet conditions across the globe Hadley circulation hot dry air rises while cold wet air sinks 2 The angle of the Earth a b Because the Earth is on a 2359 tilt certain parts of the Earth receive more or less intense sunlight at different times throughout the year Northern hemisphere points towards the Sun during our summer 3 Variation in local conditions a b h Topography or terrain is elevation slope and other features of the landthis has a large impact on Oceans amp lake cover more of the Southern hemisphere than the Northern hemisphere More deserts north of equator than south of equator Slopes can have microclimates that affect organisms living on them i If a slope has soil that drains well the plants on the top of the slope will need to develop to live in dry conditions ii Water will pool at the bottom of the slope causing plants to grow in a wetter environment Increasing elevation leads to adiabatic cooling Lake Erie has dramatic effects on our local climate causes lake effect snow but keeps us cooler during the summer 4 Variation a b El Nino and La Nina events The Pacific Decadal Oscillation PDO i Shift in surface temperatures of northern Pacific that last 2030 years uctuating between warm amp cold temperatures Stochasticity Process outcomes cannot always be predicted November 20 2015 Lecture 26 Biomes 1 Ecological Convergence 2 Temperature and precipitation predict vegetation types 3 There are a variety of names for amp ways of noting biomes 4 A quick tour of Biomes Niche Theory 1 An Ndimensional hypervolume 2 Limited resources niche packing 3 Fundamental niche vs realized niche 4 MacCarthur s warblers 5 Are niches real Ecological Convergence Convergence is a powerful force The biomes of the world Biomes are defied by temperature and rainfall Robert Whittaker defied 1 1 different biomes Those within the dashed outline vary in their biomes Different viewpoints of the Biomes highlight important factors There are many different views of the biomes No consensus on which biomes really exist Biome Types Tundra Coldest amp one of the driest climates High elevations amp high altitudes Soil is frozenin the spring a few inches will defrost and allow for shallow plant growth Taiga Boreal amp temperate evergreen forest Because this biome is so far north it Temperate Deciduous More species than boreal forest More rain than boreal Temperate Grasslands Dry biome Same average rainfall as boreal forest Hot Desert Some areas get almost no rain Diverse ora or cacti amp other succulents Cold Deserts More than twice as much rain than hot deserts Still relatively dry climate though frozen Tropical Savanna Also known as Tropical Grasslands not enough rain falls to support a forest Rolling grassland scattered with shrubs amp isolated trees Found between tropical rainforest amp desert biome Tropical Rainforest Highest production mass of any biome Most of nutrients are tied up in massive treessoils are therefore nutrient poor Epiphytesplants that grow on other plants gain nutrients from air amp water Species Ranges do not Equal Biome Ranges Many species cross biome boundaries Niche the entire set of resources a species needs to survive Formal Definition An Ndimensional hypervolume that conscribes the activity of an organism Variation in niche might explain coexistence Competition could lead to extinction of one competitor May be partitioned to allow coexistence Two Ways to look at a Niche 1 Fundamental The entire area a species could inhabit 2 Realized The area a species actually inhabits Robert MacCarthur Studied Warblers wanted to know how 5 different types of warblers ate from the same tree Found that they used different locations on the tree to look for food Clearly showed niche partitioning November 23 2015 Lecture 27 Species Interactions 1 Biotic interactions can cause strong selective pressures 2 There are plenty of ways to interact a Competition b Predation c Symbioses Competition 1 A defining example Tansley 2 Types of competition 3 How do competitors coexist 4 Is coexistence the rule Gause amp Paramecium Realized Niche is a combination of biotic abiotic and historical factors Competition When two or more species need the same resource Predation When one species eats another Symbiosis Permanent interactions of two species Includes Parasitism Mutualism Commensalism Amensalism Selective Pressures When the climate or other species require a species to adapt Leads to changes in morphology and behavior Most changes are due to pressure on two species interacting to coexist or for one species to eliminate the other Species go to great lengths to coexist Competition Can be difficult to measure in nonhumans If species are coexisting the competition must have happened in the past and has already been worked out Two Types of Competition 1 ExploitationOne species lowers the resources of another 2 InterferenceOne species prevents the other from gaining access to a resource Intraspecific Competition is competition between members of the same species while Interspecific is competition between members of different species Resources Competition is more important where resources are limited A resource is anything that an individual needs to support population survival and growth Anything that is consumed or used up therefore lowering it s availability Things that can affect survival and growth but cannot be consumed are Not resources example temperatureaffects organism but cannot be competed for Water is critical resource for animals in the desert but is not a resource for aquatic organisms Coexistence Species can exist because of resource partitioning C barnacles exist at lower depth than quotSquot barnacles Sympatric species live in close proximity Allopatric species live apart Resource Partitioning Gasterostereus aculeatus fish species Limnetic speciesliving in welllit open surface waters Benthicthe lowest level of water including the sediment surface Temporal partitioning feeding periods of tadpoles are separated by 46 weeks each year Character displacementgenetic difference difference in size beak shape that reduces competition When intraspecific competition is high enough it can lower interspecific competition Disturbance Can be a great way to foster coexistence Natural events that lower populations Keep populations of possible competitors low giving the few a good chance Balances competition scale as recovery from the disturbance occurs