Environmental Science Unit 2 – Ecological Interactions
4.1 Roles of Living Things Objectives Identify the roles of producers, consumers and decomposers Describe the concept of tropic level.
Chapter 4 Role of Living Things Producers: Photosynthesizing organisms Consumers: any organism that can’t make its own food 1.Herbivore – eats only plants 2.Carnivore – eats only herbivores or other carnivores 3.Omnivores - eats either producers or consumers 4.Scavengers – feed on bodies of dead organisms Levels of consumers : Primary – eats plants Secondary – eats animals that eat plants Tertiary – eat animals that eat animals that eat plants Decomposers: An organism that primarily feeds on dead organisms or the waste from living organisms mainly bacteria and fungi
Trophic Levels A layer in the structure of the feeding level of a systems Autotrophs: make their own food Heterotrophs: eat other organisms
4.2 Ecosystem Structure Objectives Describe food chains and food webs. Examine the effects of ecosystem structure on population size and pollution.
Food Chain: a series of organisms that transfer food between the tropic levels of an ecosystems Chapter 4 Ecosystem Structure Food Web: a network of food chains = not simple !
Example: 1. W hales were over hunted 2. Their primary food source (krill) became over abundant. 3. More krill meant more penguins & seals Chapter 4 Interconnections
Which food web represents a more mature ecosystem? Chapter 4 Diversity and Stability Which food web is more stable?
Chapter 4 Biological magnification There are increasing concentrations of pollutants in organisms at higher trophic levels of food webs
4.3 Energy in the Ecosystem Objectives Investigate the movement of energy through an ecosystem. Define ecological pyramid, and explain its relationship to energy in an ecosystem.
Energy and Food Producers use little of the sunlight that reaches them, the energy captured is used to make cells in both producers and consumers. The total amount of organic matter present in a trophic level is called biomass.
10% Law 10% Law is the main reason most food chains have five or less links. In this example – the biomass of the owl population simply could not support another level.
Ecological Pyramid Ecological Pyramid is a diagram that shows the relative amounts of energy in different trophic levels in an ecosystem.
Biomass Pyramid Ecological Pyramids can show the biomass and numbers (of organisms) as well as energy.
4.4 Chemical Cycles Objectives Describe the chemical composition of the human body. Explain the water cycle, the carbon cycle and the nitrogen cycle.
The Human Body 4 elements make up 96% of your body. Oxygen 65% Carbon 18.5% Hydrogen 9.5% Nitrogen 3.5% the rest ~4%
Describe the concept of niche. Examine how interactions between a species and its environment define the species’ niche. Chapter 5.1 Habitats & Niches
Niche refers to a populations role in its ecosystem food habitat reproduction method Chapter 5.1 Niches
includes both Biotic Competitors Predators Decomposers Population Density Abiotic Chapter 5.1 Niche influence Soil pH Soil Humidity Soil Temperature Air Temperature Wind Speed Sunlight Intensity Soil Nutrients
Hawks Owls The extinction of a population due to direct competition with another species for resources is Chapter 5.1 Competitive Exclusion Ants Crickets Overlapping niches – species can coexist Both species share the same niche – one will disappear
Chapter 5.1 Niche Diversity Keystone predator is an animal that causes a large increase in the diversity of its habitat. Predator is an organism that actively hunts other organisms.
Chapter 5.2 Evolution and Adaptation Explain how a species adapts to its niche. Describe convergent evolution and coevolution, and relate each to the concept of niche.
Chapter 5.2 Evolution Evolution, changes in a population of organisms over time.
Chapter 5.2 Evolving to the Niche Populations evolve by adapting to niches in the environment, dividing available resources (avoiding competition) Specialized species vs. Generalized species
Chapter 5.2 Specialized species vs.Generalized species SpecializedGeneralized A species closely fit to a specific environment and able to tolerate little change in that environment. A species that can survive in a variety of ecological niches. Ex: Koala feed on Eucalyptus Ex: Humans
Chapter 5.2 Convergent Evolution Convergent Evolution, is development of similar adaptations in two separate species with similar niches
Chapter 5.2 Coevolution Coevolution, species which interact closely and adapt to one-and-other (even predator & prey) - evolve together
Objectives Explain the relationship size between populations sizes of predator and prey Define symbiosis and state the effects of symbiotic relationships on populations Chapter 6.1 Relationships in the Ecosystems
Predator – a consumer that actively hunts and prey – organisms upon which predators feeds Chapter 6.1 - Predator and Prey
The populations of predator and prey are closely linked. Chapter 6.1 - Predator and Prey Population Cycles Snowshoe hare = Lynx = N1N1 N2N2
Parasitism – one organism feeds on the tissues or body fluids of another Chapter 6.1 - Parasitism Eyelash Mite Keys to Parasite survival 1.Eat enough to live and reproduce 2.But not so much that you kill your host
Symbiosis – a relationship where two species live together closely. Parasitism is an example of symbiosis. Chapter 6.1 - Symbiosis Commensalism One species benefits, and neither helps nor harms the other Mutualism Both species benefits
Chapter 6.2 Ecological Succession Objectives Describe the process of primary and secondary succession Illustrate the evolution of many species from a single ancestor during the process of island succession
Chapter 6.2 Ecosystem Successions Primary Succession Sequence of communities forming in an originally lifeless habitat
Chapter 6.2 Lichens Lichens A fungus and an algae living in a mutualistic relationship Important because able to break down bare rock using stored acid Pioneer community
Chapter 6.2 Climax Community Climax community Community that does not undergo further succession
Chapter 6.2 Secondary Community Secondary community Succession that occurs when a community has been cleared by a disturbance, but does not disturb the soil
Chapter 6.2 – Other Successions Aquatic Such as what might happen in an oxbow lake Island succesion, birds often populate unfilled niches. Darwin’s Finches
Chapter 6.3 Balance in the Ecosystem Objectives Examine the concepts of ecosystem balance and explain how humans affect that balance. Explain that disturbance is a natural part of all ecosystems, but that disturbances trigger changes in ecosystems.
Chapter 6.3 Balance in the Ecosystem All natural ecosystems are stable, they maintain a state of balance called equilibrium. Food-web is heart of the system
Chapter 6.3 Human affect on Balance Humans build houses such that salamanders vernal pools are eliminated, what might happen? VOID
Chapter 6.3 Balance Cause/Effect Causeeffect Extinction of dinosaurs Rapid evolution of mammals
Objectives Define the concept of a biome and name the eight major biomes. Illustrate where each of the eight major biomes occurs. Chapter 6.4 Land Biomes
Chapter 6.4 Biomes Biome a major type of ecosystem with distinct temperature, rainfall & organisms
Chapter 6.4 Forest Biomes Forest Biomes account for 75% of earth’s biomass Receive abundant precipitation Coniferous (sometimes refered to as ‘taiga’) Deciduous four distinct seasons, spring, summer, autumn, and winter. Rain Only account for 6% of earth’s land mass, but contain > 50% of earth’s species
Chapter 6.4 Desert and Tundra Biomes Desert Biomes account for 25% of earth’s surface Contain only 1% of earth’s biomass Receive little precipitation Desert Tundra Did you know that the Arctic Tundra is the world's youngest biome?
Chapter 6.4 Grasslands Grassland Biomes account for 22% of earth’s surface Contain only 8% of earth’s biomass Receive less precipitation than forest (may have long dry season) Steppe dry, cold, grassland Prairie dominated by herbaceous plants and grasses. Savanna two very different seasons
1.Red-tailed Hawks feed on chipmunks, what is the chipmunks role in this relationship? 2.What is the Red-tailed Hawk’s roles? 3. If the population of snowshoe hares were to suddenly decline, what would you expect to happen to the lynx population? Chapter 6.1 – Quiz (5pts)
Compare & Contrast Types of Symbiosis Types AlikeDifferent All involve close interaction between two (or more) species. HostPrey Commensalism No effect+ Mutualism++ Parasitism-+