Interdependence Amongst Organisms

Unit 6 Interdependence of Life Review

4 Needs for Earth Life

• Oxygen or Carbon Dioxide

• Water

• Food

• the right environment/shelter/temperature and space.

Multiple Select

Which of the things listed below are needed to survive on Earth?

• Water

• Air

• Waste

• Food

Multiple Choice

Which organisms listed do not need oxygen to survive

• Tigers

• flowers

• Bacteria

• Bears

Stimuli

• A stimulus is a change in an environment that causes a change in behavior.

• Organisms maintain stability by responding to changes, or stimuli, in their environment.

• A change is known as a response.

Ecosystems

• Earth has many different ecosystems

• An ecosystem is a group of interacting organisms living together in a particular place

• Everything in an ecosystem is connected.

Biotic Factors of Ecosystems

• Biotic factors are all of the living organisms in an ecosystem.

• These include food, and other animals .

• Gray squirrels need trees, and nuts to survive. When these are abundant , it is easy to survive.

• If the food supplies are limited, squirrels need to compete for survival.

Abiotic Factors in an Ecosystem

• Abiotic factors are all of the nonliving substances and conditions of an environment.

• Air, wind, water, soil, light and temerature are all abiotic features of an ecosystem.

• Organisms need these to survive.

Predator vs Prey

• Another biotic factor is the predator vs. prey relationship.

• Many predators eat squirrels for energy.

• Biotic factors are also at work inside organisms. Millions of microorganisms live in the bowels of squirrels. Some are good, and some can be bad.

Habitat

• The particular part of an ecosystem where an organism lives is its habitat.

• Different animals can live in the same ecosystems but in different habitats

• Some species can move freely from one part of an ecosystem to another.

Soil and Temerature

• Soil is an important abiotic factor of life in an ecosystem

• Eastern Gray squirrels live in trees that need healthy soil to live.

• Most organisms depend on a certain temperature range to live.

• The desert and the tundra get about the same amount of rain, but different animals live in these different biomes due to temperatures.

Biotic Organisms have affects on Abiotic features in an ecosystems

• Remember how the wolves changed the rivers in Yellowstone?

• Grasses growing in a river can slow the current which can change the oxygen concentration or temperature of the water.

Multiple Select

Which examples are biotic factors in an aquarium environment?

• fish

• light

• seaweed

• water temperature

Populations

• A population is a group of individuals of the same species in the same place at the same time

• The amount of individuals making up a population is called the population size.

• The human population of Muncie is 68,750. The world human population is 7.674 billion

Populations

• Population size can describe all species, not just humans.

• The squirrel population in my neighborhood might be 236

• The black walnut tree population in Muncie might be 670

Population Density

• For example, if there were 140 earthworms (n) in a  $4m^2$  area of your yard, the density (D) of earthworms would be 140 divided by  $4m^2$ .

•  $D=n\div area$  

•  $D=140\ earthworms\div4m^2$  

•  $D=35\ earthworms\ per\ m^2$  

Population Density

• Population density is the number of individuals of a population in a specific area

• You can calculate population density (D) of squirrels in your yard by dividing the number of individuals (n) by the area that they inhabit  $\left(D=n\div area\right)$  

Communities and Ecosystems

• All of the interacting populations in an area make up a community

• For example, a city park community may be made up of grasses, and weeds, trees and bushes, birds, squirrels, racoons, hawks and maybe even cayotes.

• A community and its abiotic (nonliving) environment make up an ecosystem.

Population Limits

• Exponential growth is rare in nature for many reasons.

• Predators, space, available food, all of these factors limit the growth of populations

• The greatest population a particular environment can support is called the carrying capacity

Land Biomes

• Land biomes are categorized as tropical forest, savanna, desert, polar and high-mountain ice, chaparral, temperate grassland, temperate deciduous forest, coniferous forest, and tundra. 

• Temperature and rainfall are the main abiotic factors that determine the kinds of organisms that live in each land biome.

Aquatic Biomes

• The major aquatic biomes are shown in this picture.

• The organisms that live in each biome are determined by the amount of saltiness, the movement, and the depth of the water.

Multiple Choice

Does this graph show a population undergoing exponential growth or one that has reached its carrying capacity?

• Exponential growth

• Carrying Capacity

Multiple Choice

What is the population density of a population of 80 squirrels in a  $$5\ km^2$$  park?

• $$20\ squirrels\ per\ km^2$$  

• 16 squirrels per sq km

• 12 squirrels per sq mi

• 10 squirrels per sq mi

Multiple Choice

What is true of the population shown in this graph?

• The population is not changing much over time.

• The population is growing unchecked.

• There are many factors at work to control the population.

• The population has increased until it reached its carrying capacity.

Carbon and Nitrogen

• For billions of years the matter that makes up living andorganisms has cycled between living and nonliving parts of the ecosystem

• Carbon and nitrogen cycle between abiotic and biotic parts of the Earth.

The Carbon Cycle

• Carbon moves back and forth between the nonliving environment and the organic molecules found in organisms. This cycle is called the carbon cycle

• Carbon in the form of carbon dioxide gas is found in the air and dissolved in water. Plants use carbon dioxide from the air or water to make the sugar glucose in the process of photosynthesis

The Water Cycle

• Water is another important element of our planet.

• Water moves through our bodies and through the hydrosphere all over Earth.

Water

• Water is always flowing from solid to liquid to gas in the hydrosphere.

• Evaporation, condensation, precipitation and collection areas are crucial to Earth's Water Cycle.

Multiple Choice

How do humans obtain the nitrogen they use in their bodies?

• by absorbing nitrogen found in the soil

• by breathing the nitrogen present in the atmosphere

• by absorbing ammonia from bacteria growing in the roots of plants

• by consuming plants or other animals

Multiple Choice

What is an ecological system called that consists of all of its biotic and abiotic factors?

• community

• ecosystem

• habitat

• pure culture

Multiple Choice

Why do plants need to obtain carbon atoms?

• Carbon is their food.

• They use carbon to breathe.

• Plants use carbon to build glucose during photosynthesis.

• Plants use carbon to build glucose during photosynthesis.

Photosynthesis

• In photosynthesis, energy from sunlight is used to rearrange the atoms in carbon dioxide and water to make a sugar called glucose.

• The energy from the sun is then stored in the glucose.

• carbon dioxide + water + light energy = glucose + oxygen

Producing Energy

• Plants use glucose for energy and as a building block to other materials that make up their bodies.

• The protiens, glucose, and carbohydrates in plants are the basis of the energy that flows through all organisms in an ecosystem.

Consumers

• Organisms that get their food from other organisms are called consumers.

• For example the elephant is a consumer because it gets it's energy from the grasses and other things it eats.

Consumers

• When animals eat producers, the energy and materials in the plant are passed to the animal.

• Animals use the energy and materials to build their bodies and carry out their lives.

Different types of Consumers

• Herbivores are consumers that only eat plants (producers)

• Carnivores are consumers that eat other animals.

• Scavengers are animals that feed on organisms that have already died.

• Omnivores eat both plants and animals

Decomposers

• Organisms that consume the remains of dead organisms are called decomposers.

• Mushrooms, bacteria, earthwormsslugs and pillbugs are all decomposers.

• Decomposers eat the remains that scavengers leave.

Food Chains

• Scientists use diagrams called food chains to trace the flow of energy through ecosystems

• The impala in this photo eats grass and foliage. Cheetah's and lions eat impalas.

Multiple Choice

What is the original source of energy for the grass, impala and the cheetah?

• grass

• impala

• cheetah

• sun

Food Chains

• Each ecosystem has its own set of food chains. Look at this food chain:

• tree → caterpillar → bluebird → fox

• The tree is the producer. When birds eat the caterpillar, the energy passes from the tree to the bird. If a fox eats the bird, the energy from the tree is passed to the fox.

Trophic Levels

• Food chains are made up of different levels calle trophic levels

• Producers are the first trophic level

• Herbivores make up the second trophic level

• Carnivores make up the third trophic level.

• Some ecosystems have more levels. if a vulture ate a dead lion, it would be a 4th trophic level.

Lost Energy?

• Only about 10% of energy is passed from one trophic level to the next.

• Most of the energy taken in is sued to carry out the activities of life.

• Ecosystems have less energy at the higher trophic levels.

Multiple Select

What are the primary producers in this image?

• caterpillar

• bear

• persimmons

• tree

Multiple Select

What are carnivores from this image?

• caterpillar

• fox

• bear

• linx

Competition

• Competition is when two or more parties strive for a goal that cannot be shared. One gains and the others lose.

Wolf Competition

• Wolves compete for rank within their pack

• Competition also happens between packs for territory, for example.

Stressful Conditions

• Sometimes competition among members of the same population occurs only during stressful conditions.

• If the population is small, plenty of resources are available for each rabbit.

• If the population increases competition occurs for all resources.

Predator and Prey

• Any animal that eats another animal is a predator.

• An animal or organism taht is eaten by another is know as prey.

• Plants are not known as prey, so herbivores are never known as predators.

Competition Among Predators

• In any given ecosystem, there are often many predators competing for a limited amount of prey.

• If there is a small amout of prey, this can lead to agression between the different predators.

• Of course, the opposite is also true.

Predator-Prey Cycles

• There is a close relationship between the population of predators and prey.

• When the prey population increases, the predator population will increase in the coming years.

• The increase in predators will cause the prey population to go down.

Predator-Prey Cycles

• The repeated pattern of change in population is calles a predator-prey cycle.

• Notice at the end of the chart, how the moose population rises as the wolf population declines.

The Carbon Cycle

• Carbon moves back and forth between the nonliving environment and the organic molecules found in organisms. This cycle is called the carbon cycle

• Carbon in the form of carbon dioxide gas is found in the air and dissolved in water. Plants use carbon dioxide from the air or water to make the sugar glucose in the process of photosynthesis

Multiple Choice

How do foxes affect the bison?

• Foxes are predators, and bison are their prey.

• Foxes keep the number of prairie dogs down.

• Foxes keep the number of wolves down.

• Foxes don't affect the bison.

Symbiotic Relationships

• Mutualism: both organisms benefit

• Commensalism: one benefits, the other is not impacted

• parasitism: one benefits while the other is harmed.

Mutualism

• Mutualism is two species are in a symbiotic relationship that benefits both of the species.

• The Moray and the cleaner shrimp both benefit from their relationship.

• The cleanerfish gets food the Moray gets cleaned.

Commensalism

• Commensalism is a symbiotic relationship where one organism benefits, but the other is neither harmed nor benefits from the relationship.

• The clownfish is protected by the anemone, the anemone's situation does not seem to be changed.

Parasitism

• Parasitism is a symbiotic relationship in which one organism benefits and another is harmed.

• Mosquitos, for instance use the blood of mammels to help in reproducing.

• Thei bites can spread disease and cause uncomfortable sores on their hosts.