ecology definition: the study of the relationships between living things and between living things...
TRANSCRIPT
Ecology• Definition: the study of the relationships between living
things and between living things and their environment.
• Origin of term: From the greek words oikos meaning “house” and logos meaning “study of”
• Modern Ecological Challenges:
1.Mass extinction: Dramatic increase in the global human population is leading to 6th mass extinction of species on Earth and the challenges your generation will have to deal with as a result.
• Thinning Ozone Layer: O3 thins over the poles, lets in UV light. UV light damages DNA.
• Climatic Changes: Dramatic swings in temperature, shifts in climate zones (tundra biome moving north), central regions of continents get drier.
Ecology• Definition: the study of the relationships between living
things and between living things and their environment.
• Origin of term: From the greek words oikos meaning “house” and logos meaning “study of”
• Modern Ecological Challenges:
1.Mass extinction:
2. Thinning Ozone Layer:
3. Climatic Changes:
Defining an Ecosystem..• Ecosystems:
• Examples:
1.________
2. __________
3.__________
4.__________
• The boundaries are usually not clear. Things move from one ecosystem to another. Pollen can blow from a forest into a field, soil can wash from a mountain into a lake, and birds migrate from state to state.
• Ecosystems have resident and transient members.
•Resident-
•Transient-
Open Note Pop Quiz
The Components of an Ecosystem• Five basic ecosystem components:
1. Energy- either chemical energy, solar energy, or heat energy
2. mineral nutrients- elements found in the soil and used by organisms to synthesize large organic molecules (like DNA)
a) Plants: use Nitrogen, Potassium, Phosphorous
b) Animals: get minerals by eating other organisms that ate plants
3. Water- Rivers, Lakes, Streams, Ground water, oceans
4. Oxygen- in atmosphere, dissolved in water
5. Living Organisms- once it is dead it becomes a “nutrient”
1. The sun is the ultimate source of energy that gets passed up the food chain.
2. All ecosystem members are interdependent.
Levels of Ecological Organization
Levels of Ecological Organization
Organism
Population
Community
Ecosystem
Biosphere
Food Chains• A food chain is a sequence in which energy is
transferred from one organism to the next as each organism eats another organism.
• Food chains are linear.
• Virginia Example:
• Wild Strawberry _________ _________ Red-⇒ ⇒ ⇒tailed Hawk
Chapter 5: Section 1
Food Webs1. A food web shows many
feeding relationships that are possible in an ecosystem.
2. A trophic level is one of the steps in a food chain or food pyramid. All of the organisms that are the same distance from a producer are on the same level.
3. Name 3 organisms that are on the same level in this diagram:
Chapter 5: Section 1
Trophic Level
ProducersProducers
Primary ConsumerPrimary Consumer(herbivore) 1°(herbivore) 1°
Secondary ConsumerSecondary Consumer2°2°
Tertiary ConsumerTertiary Consumer3°3°
DecomposersDecomposers
Mineral NutrientsMineral Nutrients
Organisms• Organisms are living things that can carry out life
processes independently.
• Life processes: reproduction, metabolism, growth, homeostasis, adaptation
• Viruses are not organisms
• Every organism is a member of a species.
• Species are groups of organisms that are closely related can can mate to produce fertile offspring.
• “For the good of the species”– Every individual is still trying to maximize their own fitness– Fitness: the extent to which an organism can produce
fertile offspring that survive to produce offspring of their own.
Populations• Populations are groups of organisms of the same species that
live in a specific geographical area and interbreed. They have access to each other.
• For example, all the field mice in a corn field make up a population of field mice.
• Fragmentation: When an organisms natural habitat becomes divided by natural or human-caused disturbance. ie Forest Fire, Clearing land for development,
• Another example: Lava flow..
• A non-example: zoo? buried pipeline?
Communities• Communities are groups of various
species that live in the same habitat and interact with each other.
• Every population is part of at least one community.
• The most obvious difference between communities is the types of species they have.
• Terrestrial communities are often dominated by a few species of plants. These plants then determine which organisms can live in that community.• Oak Forest• Cypress Swamp
Tidal Pool Community
CommunitiesTidal Pool Community
Urchin
Chiton
Sea Star
Coral
Algae
Habitat
• Habitats are places where an organism usually lives.
• Every habitat has specific characteristics that the organisms that live there need to survive. If any of these factors change, the habitat changes.
• Organisms usually cannot survive for long periods of time away from their natural habitat.
• Successful zoos are the ones that most accurately simulate the organisms natural habitat.
– Ex: nurse shark vs great white
Evolution by Natural Selection
• Natural selection is the process by which individuals that have favorable variations and are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do.• New traits are the product of genetic mutation
• Darwin proposed that over many generations the frequency of a trait in the population will increase when nature selects over many generations.
• Evolution is a change in the characteristics of a population from one generation to the next.
Frequency=# of individuals expressing a trait
total number of individuals in a population
Niche
• Fundamental Niche- the range of conditions (temp, humidity, hours of daylight, etc.) a species can potentially tolerate and the range of resources it can potentially use (food items, water)
• Realized Niche- the range of resources a species actually uses.
Niche- an organism’s way of life or role it plays in an ecosystem
Nature Selects
Life Depends on the Sun
• Energy from the sun enters an ecosystem when plants use sunlight to make sugar molecules.
• This happens through a process called photosynthesis.
Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to produce carbohydrates and oxygen.
From Producers to Consumers
Because plants make their own food, they are called producers.
• Some producers get their energy directly from the sun by absorbing it through their leaves as light and heat.
• A producer is an organism that can make organic molecules from inorganic molecules-- usually through photosynthesis.
• Producers are also called autotrophs, or self-feeders.
Organisms that get their energy by eating other organisms are called consumers.
• A consumer is an organism that eats other organisms or organic matter instead of producing its own nutrients or obtaining nutrients from inorganic sources.
• Consumers are also called heterotrophs, or other-feeders.
Chapter 5: Section 1
An Exception to the Rule
• Deep-ocean communities of worms, clams, crabs, mussels, and barnacles, exist in total darkness on the ocean floor, where photosynthesis cannot occur.
• The producers in this environment are bacteria that use hydrogen sulfide present in the water to create organic molecules through chemosynthesis.
• Other underwater organisms eat the bacteria or the organisms that eat the bacteria.
Chapter 5: Section 1
What Eats What?• Organisms can be classified by what they eat.
• Types of Consumers:
• Herbivores
• Carnivores
• Omnivores
• Decomposers
Chapter 5: Section 1
Burning the Fuel• All heterotrophic organisms obtain energy from the food it eats.
• This food must be broken down within its body to release energy. • Part of the energy is used to carry out daily activities.• Excess energy is stored as fat (animals) or sugar (plants).
• The process of breaking down food to yield energy is called cellular respiration.• Cellular Respiration is the process by which cells produce energy
from carbohydrates; atmospheric oxygen combines with glucose to form water and carbon dioxide.
• Cellular respiration occurs inside the cells of most organisms.
• Cell Respiration Equation:
Chapter 5: Section 1
Energy Transfer
• Each time an organism eats another organism, an energy transfer occurs.
• This transfer of energy can be traced by studying food chains, food webs, and trophic levels.
• Each time energy is transferred by organism eating organisms from a lower trophic level, most of the energy is lost as heat and waste.
• Therefore, less energy is available to organisms at higher trophic levels.
• One way to visualize this is with an energy pyramid.
Chapter 5: Section 1
Chapter 5: Section 1
What does this suggest about the area (square meters..etc) needed by each organism?
Trophic Levels• Each layer of an energy pyramid represents one
trophic level.
• Producers form the base of the energy pyramid, and therefore contain the most energy.
• The pyramid becomes smaller toward the top, where less energy is available. The volume of each layer of the pyramid = the energy that has been passed up from the trophic level beneath it.
Chapter 5: Section 1
Energy Loss Affects Ecosystems
• Decreasing amounts of energy at each trophic level affects the organization of an ecosystem.
1. Energy loss affects the number of organisms at each level.
2. Energy loss limits the number of trophic levels.
3. Due to the limited amount of energy at each level, the number of 3° or 4° consumer species in any one ecosystem is small compared to the number of primary consumers.
Chapter 5: Section 1
The Carbon Cycle
Chapter 5: Section 2
The Carbon Cycle1. The carbon cycle is the movement of carbon from the
nonliving environment into living things and back
2. Carbon is the essential component of proteins, fats, and carbohydrates, which make up all organisms
3. Increased levels of carbon dioxide may contribute to global warming.
4. Carbon moves through the atmosphere, hydrosphere, geosphere and biosphere:
1. Producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis.
2. Consumers obtain carbon from the carbohydrates in the producers they eat.
Chapter 5: Section 2
Ecological Succession
• Ecological succession is a gradual process of change and replacement of the types of species in a community.
• Each new community that arises often makes it harder for the previous community to survive.
Chapter 5: Section 3
Year 1:annual plants
Year 2: perenni
al plants and
grasses
Year 3-10shrubs, shade-
intolerant plants
About 20 Years:
young forest, shade-tolerant
seedling appear
After about 150 years: Climax community
Ecological Succession
• Primary succession is a type of succession that occurs on a surface where no ecosystem existed before. It begins in an area that previously did not support life.
1. Primary succession can occur on rocks, cliffs, or sand dunes. A pioneer species is a species that first colonizes an uninhabited area. Over time, a pioneer species will make the new area habitable for other species.
2. A climax community is the final, stable community in equilibrium with the environment.
3. Even though a climax community may change in small ways, this type of community may remain the same through time if it is not disturbed.
Ecological Succession
• Natural fires caused by lightning are a necessary part of secondary succession in some communities.
• Minor forest fires remove accumulations of brush and deadwood that would otherwise contribute to major fires that burn out of control.
• Some animal species also depend on occasional fires because they feed on the vegetation that sprouts after a fire has cleared the land.
• Old-field succession is a type of secondary succession that occurs when farmland is abandoned.
• When a farmer stops cultivating a field, grasses and weeds quickly grow and cover the abandoned land.
• Over time, taller plants, such as perennial grasses, shrubs, and trees take over the area.
Chapter 5: Section 3
Ecological SuccessionChapter 5: Section 3
Ecological Succession
• Primary succession can occur
1.on new islands created by volcanic eruptions
2.in areas exposed when a glacier retreats
3.any other surface that has not previously supported life
• Primary succession is much slower than secondary succession. This is because it begins where there is no soil.
1
2
3
Ecological Succession
• The first pioneer species to colonize bare rock will probably be bacteria and lichens, which can live without soil.
• The growth of lichens breaks down the rock, which with the action of water, begins to form soil.
Chapter 5: Section 3