What is Ecology?

The study of organisms and their environment

Biotic vs. Abiotic See if you know the difference between the two!

Abiotic or Biotic? Biotic

Abiotic or Biotic? Abiotic

Abiotic or Biotic? Abiotic

Abiotic or Biotic? Biotic

Biotic Factors Review

Biotic Factors Are the living things or their materials that directly or indirectly affect an organism In its environment. Some biotic factors include: Parasitism disease predation

Biotic Factors Producers Organisms that make their own food. Ex- Plants & some bacteria Consumers: Organisms that eat (consume) other organisms for energy (animals)

Biotic Factors Decomposers: Consumers that eat waste products for energy. Waste products are feces, urine, fallen leaves, dead animals. (Fungi, some bacteria)

Scavengers Organism that eats other dead organisms

Abiotic Factors Are those non-living physical and chemical factors which affect the ability of organisms to survive and reproduce Includes things such as: sunlight temperature type of soil or rock water availability

Feeding Relationships Autotrophs: Organisms that make their own food (plants and some bacteria) Heterotrophs: Organisms that eat other organisms (they cannot make their own food)

Feeding Relationships Herbivores: eat plants (cows) Carnivores: eat meat (wolves) Omnivores: eat plants and meat (humans)

Levels of Organization

Review: What are the Simplest Levels? Atom Molecule Organelle Cell Tissue Organ System

Which Level of Ecological Organization Which Level of Ecological Organization? Take this quiz to see if you can tell the difference between the two!

Which Level? Organism – An Individual with all characteristics of life

Which Level of Organization? Population – groups of organisms of the same species

Which Level of Organization? Biological Community – group of populations living together

Which Level of Organization? Ecosystem: the living and nonliving parts that are interacting together

Which Level of Organization? Biosphere: The earth that supports life.

What level of organization? Organism

What level of Organization? Community

What level of Organization? Population

Habitat & Niche Habitat is where something lives Niche is an organism’s total way of life (how it eats, competes with others)

FYI- Niche Includes all its interactions with the biotic and abiotic parts of the environment Each type of organism occupies its own niche to avoid competition with other types of organisms Two species can share the same habitat but not the same niche Example: Ants and bacteria both live in the dirt (habitat) but have different niches. Ants eat dead insects and bacteria eat dead leaves, dead logs, and animal waste. So ants and bacteria don’t compete for resources.

Survival Relationships Predator-prey: predators are consumers that hunt and eat other organisms called prey.

Survival Relationships Symbiosis: relationship in which one species lives on, in, or near another species and affects its survival. 3 Types: Mutualism Commensalisms Parasitism

Mutualism type of symbiosis in which both species benefit. Ex. Clownfish living in the sea anemones. It provides protection for the fish, and attracts potential food for the anemones.

Commensalism type of symbiosis in which one species benefits and the other species is neither harmed nor benefited Example: Spanish moss grows on the branches of trees. The moss gets a habitat and the tree gets nothing.

Parasitism one species benefits and the other species is harmed. Parasite: organism that harms but does not usually kill another organism Host: organism that is harmed by a parasite Ex. Ticks feed on dogs, people, etc. The ticks get food (blood) and the hosts lose blood and can be infected with disease.

Abiotic Factors- Non-living parts of the environment. Ecology- Study of interactions between organisms and their environment. Consumer-organisms eat others for energy “heterotrophs” Producer- Uses the sun to make food “autotroph” Scavenger-eats dead organisms Decomposer- break down dead organisms and cause decay 1. Organism- individual with all characteristics of life. 2. Populations- groups of organisms of the same species. Biotic Factors- All the living parts of the environment The 5 Levels of Ecological Organization 3. Community- group of populations living together. 5. Biosphere- part of the earth that supports life 4. Ecosystem- living & nonliving parts interact together.

End of Day One Notes

Trophic levels and food chains Trophic level: A feeding level in an ecosystem.

Trophic Levels Eaten by Eaten by 1st trophic level: producers (make their own food) Eaten by Eaten by 2nd trophic level: primary consumer (eats plants) Bacteria 3rd trophic level: secondary consumer (small carnivore) Eaten by 4th trophic level: tertiary consumer (large carnivore) Last trophic level: decomposer (eats dead animals)

Energy Pyramid Every time an organism eats, it obtains energy from its food. So energy is transferred from the 1st trophic level to the 2nd trophic level to the 3rd trophic level and so on. Some of this energy is lost along the way during an organism’s metabolism and as heat. This energy can be measured in kilocalories (kcal).

Energy Pyramid Picture that shows how much energy is transferred among the different trophic levels in a food chain; energy is lost as you move up the pyramid. Food chain: lineup of organisms that shows who eats who. Shows how matter and energy move through an ecosystem.

Food Webs A food web is a network of connected food chains. More realistic than a food chain because most organisms feed on more than one species for food.

Trophic Level Energy Available 4th Tertiary consumers 10 kcal/m2/year 3rd Secondary consumers 100 kcal/m2/year 2nd Primary consumers 1000 kcal/m2/year 1st Producers 10,000 kcal/m2/year

Some energy is lost as heat and the rest is consumed or excreted as waste.

Practice with Food Chains & Food Webs

Identify the food chains inside the food web.

End of Day 2 Notes

Cycles in Nature There is only a limited amount of resources (water, oxygen, nitrogen, carbon) on the earth. In order to keep these resources available to organisms, they must be recycled after they are used. Cycle: a process that recycles a resource so that you end up with what you started with.

Nitrogen Cycle 1. Nitrogen fixation: Bacteria in the ground change nitrogen from the atmosphere (N2) to different nitrogen compounds 5. Denitrification: Bacteria change the nitrogen compounds back to N2 and release it to the atmosphere 2. These bacteria live in plants and transfer the nitrogen compounds to the plants 4. Bacteria eat the dead animals and animal waste and take in the nitrogen compounds 3. Animals eat the plants and take in the nitrogen compounds

Nitrogen Cycle

Water Cycle 2. Seepage: Water seeps into the ground and plants use it 3. Transpiration: Plants give off water to the atmosphere 1. Precipitation: Rain and snow fall from the atmosphere to the earth 2. Runoff: Extra water runs off the land to lower-lying bodies of water 3. Evaporation of water from the bodies of water back into the atmosphere

Water Cycle

Carbon Cycle 1. Carbon dioxide (CO2) and oxygen (O2) are found in the atmosphere 2. Plants use CO2 to make their own food (photosynthesis) 2. Animals and plants use the O2 to make energy (respiration) 3. During photosynthesis, plants release O2 back into the atomosphere 3. During respiration, animals and plants release CO2 back into the atomosphere

Carbon Cycle

Population Size

Populations What is a population? What are some factors that can contribute to the size of a population?

Organism Interactions Limit Population Size Organisms depend on each other for: So what happens when these factors change? Protection Food Reproduction Shelter

Organism Interactions Limit Population Size Predation: What could happen if a predator is introduced to a population and there are no organisms to eat it? Unchecked for many years, the snakes caused the extinction of nearly every native bird species on the Pacific island of Guam

Organism Interactions Limit Population Size 2. Competition - What can happen if resources become limited?

Organism Interactions Limit Population Size 3. Crowding & Stress As pop. Increase in size and start straining their resources, they may become stressed. What are some examples of stress symptoms? Aggression Decrease in parental care Decreased fertility Decreased resistance to disease

How do you determine population size? Growth rate—amount that a population’s size changes over time Birth rate—number of births occurring during a period of time (ADD) -- Death rate (or mortality rate)—number of deaths in a period of time (SUBTRACTS)

How do you determine population size? Birth rate – death rate = growth rate - Positive number means the pop. is growing - Negative number means the pop. is shrinking

Human population size Other things that affect a population’s numbers: Life expectancy—how long on average an individual is expected to live US men: 72 yrs, US women: 79 yrs Immigration—individuals moving into a population (ADDS) Emigration—individuals moving out of a population (SUBTRACTS)

What can affect population size? When you figure out the number of individuals living in a certain area, this is called the population density. There are two limiting factors (biotic and abiotic) that can affect the pop. density Limiting factor—any biotic or abiotic factor that restrains the growth of a population

What are limiting factors? Density-independent factors—factors that affect the population regardless of the population’s size Ex: fires, climate Density-dependent factors—factors whose effects on the population depend on the population’s size Ex. food shortages, disease

Density- dependent or Density- independent Density- dependent or Density- independent? Take the following quiz to find out!

Predation Volcanic eruption Chemical pesticides Parasitism Forest fire Density-dependent Volcanic eruption Density-independent Chemical pesticides Parasitism Density-dependent Forest fire Density-independent Migration

Communities

FYI: How are communities formed? Communities are made of several populations living together Think back to population size. What are some limiting factors that can affect a community?

FYI: Forming Communities What would happen if people stopped cutting the grass in their yards? 1. The grass would get taller & weeds would grow 2. Later, bushes would grow; trees would appear, and different animals would enter the area 3. After 30 years, it would eventually become a forest…BUT WHY?

Forming Communities Succession—orderly, natural changes and species replacements that take place in the communities of an ecosystem

Communitites Primary succession—development of a community in an area that did not previously exist Ex: new volcanic island, bare rock, sand dune Happens slowly

Communities Pioneer species—usually small, fast growing, and fast reproducing organisms that are first to colonize land after a disturbance Example of primary succession: lichens

Communities Secondary succession—sequential replacement of species that follows a disruption of an existing community Example of secondary succession: grasses, weeds

Communities Climax community—stable end point of a community after succession takes place

End of Day 3 Notes