Unit 1: Ecology

The flow of energy through an ecosystem is one of the most important factors that determines the system’s capacity to sustain life.

Adenosine Triphosphate (ATP) Adenine Ribose 3 phosphate groups – the bonds between the phosphates are where the energy is stored – bonds must be broken to release the energy

Reminder: ATP/ADP Cycle

Interactions and Interdependence Ecology The study of interactions and relationships between organisms and their environment.

Interactions and Interdependence What non-living things in their environment do organisms interact with? Sunlight, air, water, soil, rocks In what ways are these nonliving things essential to organisms? Photosynthesis, Oxygen in air, bacteria live in soil, mosses on rocks, etc.

Biosphere Contains the combined portions of the planet in which all of life exists, including land, water, and air (atmosphere)

Levels of Organization

Producers Sunlight is the main energy source for life on Earth.

Producers Producers are also known as autotrophs – they make their own food Two types: Photo-autotrophs: use sunlight in process of photosynthesis Chemo-autotrophs: use inorganic chemicals

Producers -- Energy from the Sun Photosynthesis Using light energy to power chemical reactions to turn Carbon Dioxide (CO2) and water into Oxygen(O2) and sugars. 6CO2 + 6H2O 6O2 + C6H12O6 Light energy

Producers -- Energy from the Sun On land, plants are the main autotrophs. In freshwater ecosystems, algae are the main autotrophs

Cellular Respiration Cellular respiration: Both autotrophs & heterotrophs perform this to release energy from food to do cellular work. 6O2 + C6H12O6 --> 6CO2 + 6H2O

Biochemical pathways

Consumers Heterotrophs Consumers that rely on other organisms for their energy and food supply. Indirect use of sun’s energy

Consumers -- Heterotrophs Herbivores — eat plants (rabbit) Carnivores — eat other animals Omnivores — eat both plants and animals Detritivores — feed on plant and animal remains called detritus. Decomposers — break down organic matter (bacteria and fungi).

Feeding Relationships Energy flows through an ecosystem in one direction: Sunlight Producers  Consumers

Energy Transformations Only 10% of the energy at each trophic level is passed on to the next: Primary – 1st Secondary – 2nd Tertiary – 3rd Quaternary – 4th The other 90% is lost as heat when consumers burn food during cellular respiration (this is good because it helps us to maintain our body temperature!)

Trophic Levels

Food Chain A series of steps in which organisms transfer energy by eating and being eaten; travels in one direction. Always begins with producers who store energy in the chemical bonds of the foods they make. Stored energy is passed on to consumers when they eat producers or other consumers.

Feeding Relationships Food Web A network of feeding relationships in an ecosystem

Aquatic Food Web

Ecological Pyramids A diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain. Energy Pyramid Biomass Pyramid Pyramid of Numbers

Ecological Pyramids Energy Pyramid Shows the relative amount of energy available at each trophic level. Organisms use about 10 percent of this energy for life processes. The rest is lost as heat. Pyramid of Numbers Shows the relative number of Individual organisms at each trophic level. Biomass Pyramid Represents the amount of living organic matter at each trophic level. Typically, the greatest biomass is at the base of the pyramid.

Recycling in the Biosphere Matter and energy move differently through the ecosystem. Energy flows one way – some is lost as heat, only 10% of energy is used directly by organisms at each trophic level Matter is RECYCLED through the ecosystem Law of Conservation of Matter Matter can be transformed

Ecosystems, Communities, & Population Growth

Factors in an Ecosystem Biotic factors: living organisms with which an organism might interact. Ex: insects, plants, etc. Abiotic Factors: physical or nonliving factors with which an organism might interact. Ex: sunlight, wind, soil, etc.

List the Biotic Factors in the picture

List the Abiotic factors in the picture

Community Interactions Competition occurs when organisms attempt to use an ecological resource in the same place and at the same time. Resource = any necessity of life Examples: water, nutrients, light, food, space

Community Interactions Predation occurs when one organism captures & feeds on another organism Ex: lions hunt deer

Community Interactions Symbiosis: 3 main types Mutualism = both organisms benefit from the relationship Commensalism = one organism benefits while the other organism is neither helped nor harmed Parasitism = one organism benefits at the expense of the other organism

Mutualism Butterflies and flowers

Commensalism Barnacles on a Whale

Parasitism HEARTWORMS

Ecological Succession Predictable changes that occur in a community over time Primary succession: occurs on surfaces where no soil exists Examples: after a volcanic explosion where the land is covered with lava or ashes or on bare rock exposed by glacier melt Pioneer species: first species to populate the area (often lichens)

Primary Succession

Ecological Succession Secondary succession: follows a disturbance that changes an existing community without removing the soil Example: wildfires, plowing, logging industry

Population Growth Affected by 3 factors: # of births # of deaths # of organisms arriving or leaving: Immigration and emigration

Exponential Growth Exponential growth occurs when organisms in a population reproduce at a constant rate Tends to happen when resources are unlimited Example – bacteria 2 split to become 4 4 split to become 8 8 split to become 16 and so it grows on & on

Exponential Growth

Logistic Growth Happens when resources become less available so growth will slow or stop Notice the pattern When does the growth slow & when does it level out?