Ecosystems and Conservation Biology Eric Molina

The Path of Energy and Chemicals in a Ecosystem Every organism requires energy to carry out life’s process: Growing Moving Reproducing

Photosynthetic Producers Plants that convert light energy from sunlight to the chemical energy of organic compounds.

Consumers Obtain chemical energy by feeding on the producers or other consumers

Decomposers Break down waste and dead organisms

The Path of Energy As living things use chemical energy, they release thermal energy (Heat) to the surroundings

The Path of Energy Energy is not recycled within an ecosystem, but flows through it and out. Producers must continue to receive energy so they can transfer that energy; if not the ecosystem could not survive.

Energy Flow Energy Flows Through an Ecosystem + Chemical Cycles (carbon, oxygen, nitrogen) = Feeds the Ecosystem

Food Chains Trophic Level – A feeding level in an ecosystem Food Chain – the pathway of food transfer from one trophic level to another

Producers Supports all other tropic levels Terrestrial Ecosystem (on land) plants are the producers Aquatic Ecosystem (sea) phytoplankton photosynthetic protist bacteria multicellular algae aquatic plants are the producers

Consumers In trophic levels above producers Categorized by what they eat Herbivore – eats only producers You have to say it this way because in aquatic conditions producers are not necessarily plants (phytoplankton) No just plant eaters

Carnivore Eats other consumers

Omnivore Eats both producers and other consumers

Consumers Consumers can be categorized by their position in a food chain: Primary Consumers – feeds directly on producers In Terrestrial Ecosystem – insects, birds (eat seeds / fruit) - grazing mammals like deer In Aquatic Ecosystem – can be zooplankton (protist and microscopic animals – like small shrimp)

Consumers Secondary Consumers – eat primary consumers In Terrestrial Ecosystem – small mammals and reptiles (eat insects, as well as large carnivores that eat rodents and grazing mammals) In Aquatic Ecosystem – Small fish (eat zooplankton)

Tertiary Consumers – (3 rd Level Consumer) eat secondary consumer In Terrestrial Ecosystem – snake (eating a mouse) Decomposers – eat waste and remains of dead organisms Degradation - The reduction of a chemical compound to one less complex, as by splitting off one or more groups. Consumers

Detritus – Waste and remains of dead organisms decomposers Consumers that obtain energy by feeding on and breaking down detritus

Consumers - Scavengers

In All Ecosystems  An ecosystems main decomposer is bacteria and fungi Found in enormous numbers in the soil and sediment at the bottom of lakes and oceans They recycle chemicals within an ecosystem

Food Webs In an ecosystem the feeding relationship is usually more complicated than a simple food chain Because of the variety of species; animals and plants Food Web – the pattern of feeding by interconnected and branching food chains

Energy Flow Through an Ecosystem All organisms require energy for growth, reproduction, and movement (if possible) The amount of energy is limited and divided among the different trophic levels This influences the types and numbers of organisms in an ecosystem

Productivity of an Ecosystem The energy “Budget” of each ecosystem (for most) begins with sunlight Much of the sunlight that bombards the Earth everyday bounces back into space or it is absorbed by the atmosphere. Only 1 % of light energy that reaches Earth is captured by photosynthesis. Biomass – Organic material manufactured by producers - Even this 1% is enough to produce billions of kilograms of organic material.

Productivity of an Ecosystem Primary Productivity – the rate at which producers in an ecosystem build biomass This sets the energy “Budget” for an ecosystem This determines the energy available throughout the ecosystem

Ecological Pyramids Energy is spent at each step of the food web As each consumer feeds, some energy is transferred from the lower trophic levels to the higher trophic levels. Most available energy stored in the prey organisms biomass is lost.

Energy Diagrams 3 Types of Diagrams that describe; energy, biomass, and numbers of organisms at different trophic levels: 1. Energy Pyramids (AKA Food Pyramid) Emphasizes the energy loss from one trophic level to the next. On average – only 10% of available energy at a trophic level is converted to biomass in the next trophic level. 90% is lost as HEAT. - This is the reason it takes lots of vegetation to support the higher trophic levels - Not enough left for the top of the energy pyramid

Energy Pyramids 2. Biomass Pyramid Represents the actual biomass (dry mass of all organisms) in each trophic level in an ecosystem Most biomass pyramids narrow sharply from the producer at the base to the top Some aquatic ecosystems the primary consumer (2 nd Level) consume producers in such large numbers that they would appear top heavy

Energy Pyramids 3. Pyramid of Numbers Depicts the number of idividual organisms in each trophic level of an ecosystem Organized like energy pyramids Emphasizes how few top-level consumers an ecosystem can support Exception would be when one tree would support hundreds of insects

Energy Pyramids : Pyramid of Numbers

Chemical Cycles It is possible that life’s important chemicals travel the entire globe as they cycle through and between ecosystems.

Chemical Cycles Basic Pattern 1. Producers incorporate chemicals from nonliving environment into organic compounds 2. Consumers eat producers; process chemicals and release some as waste 3. Organisms die, decomposers break them down they go into soil, water, and air. Producers incorporate chemicals and the process starts again. - Part of chemical cycle involves nonliving process like rain and fires.

The Carbon and Oxygen Cycle Carbon and Oxygen movement through an ecosystem are linked; so they are described together. Carbon is Found: In the atmosphere as CO₂ gas In water as Bicarbonate HCO 3 Producers use Carbon and Oxygen atoms to form organic compounds during photosynthesis - Also during cellular respiration both producers and consumers break down organic compounds such as sugars and release CO ₂ gas as a waste product.

The Carbon and Oxygen Cycle CO₂ is also released to the atmosphere by decomposers when they break down detritus. Detritus – Waste and remains of dead organisms Nonliving processes in the carbon cycle: Burning fossil fuels (oil, coal, natural gas) release CO₂ to the atmosphere Forest Fires Volcanic eruptions Also add CO ₂ to the atmosphere

The Carbon and Oxygen Cycle

The Nitrogen Cycle Remember: Nitrogen (N) is found as amino acid in all living things Although 80 % of Earth’s atmosphere is Nitrogen gas; most organisms can only use Ammonium (NH₄⁺) and Nitric Acid (NO₃⁻) Nitrogen Fixation – the process where some bacteria convert Nitrogen to ammonia (NH₃⁻) - They live in the soil, on the roots of plants like peas, beans, etc. - In the soil ammonia picks up another H molecule form water form ammonium.

The Nitrogen Cycle Nitrification – the process by which certain bacteria convert ammonium to nitrates. Producers absorb the ammonium and nitrates from the soil and use them to build amino acids, proteins, and nucleic acids. Consumers eat producers to obtain nitrogen Decomposers release nitrogen (as ammonium) from wastes and decaying organisms. Cycle Continues

The Nitrogen Cycle

The Water Cycle Mostly involves nonliving processes Sun evaporates water Water vapor is added to the atmosphere water vapor cools and condenses Falls as precipitation Plants absorb water from soil Consumers obtain water from eating and drinking water

The Water Cycle Transpiration – Evaporation from plant’s leaves. A large amount of water exist the plants by this process. The rest of the water re-enters the cycle by “running-off” to rivers, lakes, and oceans.

The Water Cycle

Human Activities vs. Ecosystem On Chemical Cycles: Deforestation – The clearing of forest for agriculture, lumber, and other uses This can affect the Carbon – cycle by eliminating plants that absorb CO₂ during photosynthesis Industrialization also increases atmospheric CO₂, as industries and more cars burn more fossil fuels.

Human Activities vs. Ecosystem Greenhouse Effect – the process by which atmospheric gases trap heat Global Warming – The theory in which Earth’s average temperature rise because of the addition of greenhouse gases. Greenhouse gases – carbon dioxide, methane, & water vapor

Human Activities vs. Ecosystem Nitrogen Cycle Impacts Caused primarily by moving large amounts of Nitrogen compounds into the water or air By sewage treatment plants released Nitrogen compounds into streams and rivers Fertilizers applied to crops; excess run into nearby streams and ponds.

Human Activities vs. Ecosystem Eutrophication – the rapid growth of algae in bodies of water, due to high levels of Nitrogen and often phosphate. As the algae die, the bacteria decomposing them use up so much of the Oxygen in the water that it cannot support life

Human Activities vs. Ecosystem Acid Rain – the precipitation that contains nitric and/or sulfuric acids. The Clean Air Act – a political policy that has “in theory” helped reduce the acid rain problem in the U.S.

Human Activities vs. Ecosystem Water Cycle Impacts Deforestation can also impact the water cycle A primary way that fresh water returns to the atmosphere is transpiration from dense tropical forest. Drawing water from rivers or underground aquifers for household use or for crops Florida Aquifer

Effects of Pollution Desertification – Areas where dry climates, farming, overgrazing, seasonal drought, and climate change can turn farmland into a desert 40% of earth land is in danger of becoming decertified. Deforestation can lead to severe erosion, which can lead to desertification

Effects of Pollution Pollution – The addition of substances to the environment that results in a negative effect. Biological Magnification – The process by which pollutants become more concentrated in successive trophic levels of a food web

Effects of Pollution - Biological Magnification DDT (1971) Used to control mosquitoes and pest As you moved up the food chain concentration of DDT increased in fatty tissue Caused bird egg shells to become easily breakable Top level consumers such as pelicans and eagles were seriously effected After the U.S. banned DDT populations of these birds made a dramatic recovery.

Effects of Pollution - Biological Magnification DDT

Biodiversity A term that encompasses the variety of life on Earth The rain forest are one of the most diverse ecosystems on Earth The variety of ecosystems as well as genetic variety are other examples of biodiversity

Renewable and Nonrenewable Resources Resource – any necessity of life, such as water, nutrients, light, food,or space. Renewable Resource – can be produce or replaced by a healthy ecosystem.

Renewable and Nonrenewable Resources Nonrenewable Resource – natural processes cannot replenish them within a reusable amount of time.

Sustainable Resources Sustainable Development – using resources in such an environmentally conscious way Ecological Footprint – describes the total area of functioning land and water ecosystem needed both to provide the resources an individual or population generates.

Sustainable Resources Ecological Footprint Ecologist use footprint calculations to estimate the biosphere’s carrying capacity for humans There are large scale impacts: Waste Spills Oil Spills Greenhouse gases Ozone depletion Surface & ground pollution

Biodiversity Many of the species in an ecosystem are interconnected Some are connected by food Shelter Other needs If a species disappears it effects the health of the entire ecosystem

Biodiversity Human Value A source of inspiration / beauty As a Source of Oxygen Food Clothing Shelter Development of medicines 25% of all medicines contain substances originally derived from plants

Threats to Biodiversity As population increases more land is needed for agriculture, roads, and communities Also for obtaining natural resourses Lumber Coal Minerals May harm or even destroy natural communities. Coal Mine

Threats to Biodiversity Urbanization - is the physical growth of urban areas as a result of rural migration and even suburban concentration into cities, particularly the very large ones.