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 Herbivore – eats only plants Carnivore – eats only herbivores or other carnivores Omnivores - eats either producers or consumers 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 Heterotrophs: eat other organisms Autotrophs: make their own food

4.2 Ecosystem Structure Objectives Describe food chains and food webs. Examine the effects of ecosystem structure on population size and pollution.

Chapter 4 Ecosystem Structure Food Chain: a series of organisms that transfer food between the tropic levels of an ecosystems Food Web: a network of food chains = not simple !

Chapter 4 Interconnections Example: Whales were over hunted Their primary food source (krill) became over abundant. More krill meant more penguins & seals

Chapter 4 Diversity and Stability Which food web represents a more mature ecosystem? 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 More

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 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%

The Water Cycle

The Carbon Cycle

The Nitrogen Cycle

Chapter 4 Quiz

Chapter 5.1 Habitats & Niches Describe the concept of niche. Examine how interactions between a species and its environment define the species’ niche. Species with narrow niches are called specialists (e.g. anteater). Species with broad niches are called generalists (e.g. common crow).

Niche refers to a populations role in its ecosystem Chapter 5.1 Niches Niche refers to a populations role in its ecosystem food habitat reproduction method Species with narrow niches are called specialists (e.g. anteater). Species with broad niches are called generalists (e.g. common crow).

Chapter 5.1 Niche influence includes both Biotic Competitors Predators Decomposers Population Density Abiotic Soil pH Soil Humidity Soil Temperature Air Temperature Wind Speed Sunlight Intensity Soil Nutrients

Chapter 5.1 Competitive Exclusion Crickets Ants Overlapping niches – species can coexist Hawks Owls Both species share the same niche – one will disappear The extinction of a population due to direct competition with another species for resources is

Chapter 5.1 Niche Diversity Predator is an organism that actively hunts other organisms. Keystone predator is an animal that causes a large increase in the diversity of its habitat.

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 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

Chapter 5.3 Populations Unchecked populations growth leads to exponential growth

Chapter 5.3 Populations A population’s limit as defined by its ecosystem is its carrying capacity

Chapter 5.3 Limiting Factors Density-independent limiting factors Human Disturbance Climate Natural Disasters Population Size Predation Water Availability Living Space Parisitism Food Competition Disease Density-dependent limiting factors

Chapter 5 Quiz

Environmental Science Chapter 6 - Ecosystem Balance

Chapter 6.1 Relationships in the Ecosystems 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 - Predator and Prey Predator – a consumer that actively hunts and prey – organisms upon which predators feeds

Chapter 6.1 - Predator and Prey Population Cycles The populations of predator and prey are closely linked. Snowshoe hare = Lynx = N1 N2

Chapter 6.1 - Parasitism Parasitism – one organism feeds on the tissues or body fluids of another Eyelash Mite Keys to Parasite survival Eat enough to live and reproduce But not so much that you kill your host

Chapter 6.1 - Symbiosis Symbiosis – a relationship where two species live together closely. Parasitism is an example of 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 Community that does not undergo further succession

Chapter 6.2 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? Chapter 6.3 Human affect on Balance VOID

Chapter 6.3 Balance Cause/Effect Extinction of dinosaurs Rapid evolution of mammals

Define the concept of a biome and name the eight major biomes. Chapter 6.4 Land Biomes 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 Biomes Biome a major type of ecosystem with distinct temperature, rainfall & organisms

Forest Biomes account for 75% of earth’s biomass 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 Steppe dry, cold, grassland Prairie 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

Chapter 6.1 – Quiz (5pts) Red-tailed Hawks feed on chipmunks, what is the chipmunks role in this relationship? What is the Red-tailed Hawk’s roles? If the population of snowshoe hares were to suddenly decline , what would you expect to happen to the lynx population?

Compare & Contrast Types of Symbiosis Types Alike Different All involve close interaction between two (or more) species. Host Prey Commensalism No effect + Mutualism Parasitism -