Ecology Chapter 3

Define ecology.

The study of the interactions of organisms with one another and their environment.

What are the levels of organization?

Individual/species, population, community, ecosystem, biome, and biosphere.

What are biotic factors?

They are the living components of an ecosystem, such as animal interaction, plants/fungi/protists, and bacteria.

What are abiotic factors?

They are the non-living components of an ecosystem, such as temperature, precipitation, soil characteristics, and sunlight.

What are producers (autotrophs)?

They are organisms that produce energy-rich compounds, such as plants, certain species of bacteria, and algae.

What is photosynthesis?

The process of converting CO2 + H2O into sugars + oxygen using sunlight energy.

What is chemosynthesis?

The use of chemical energy from CO2, hydrogen sulfide, and oxygen to produce carbohydrates (no light).

How is it possible for certain organisms to inhabit deep sea hydrothermal vents (life without light)?

Chemosynthesis makes this possible.

What prevents oceans from becoming toxic?

Chemosynthetic organisms (bacteria) prevent oceans from becoming toxic.

What happens to the microbial mats that chemosynthetic organisms (bacteria) create?

What happens is that grazers such as snails, limpets, and scale worms eat the microbial mat, and predators come to eat those grazers.

What are consumers (heterotrophs)?

They are organisms that rely on other organisms for energy and nutrients.

What are carnivores?

They are a type of consumer that kills and eats other animals.

What are scavengers?

They are a type of consumer that consumes carcasses.

What are decomposers?

They are a type of composer that chemically breaks down organic matter.

What is detritus?

Small pieces of decaying plant and animal remains that decomposers produce.

What are detrivores?

They are a type of consumer that feeds on the detritus produced by decomposers, like earthworms.

What are herbivores?

They are a type of consumer that eats plants.

What are omnivores?

They are a type of consumer that eats plants and animals.

What is a food chain?

It is a diagram that shows how energy in food flows from one organism to another.

What is a food web?

It is a diagram that shows the feeding interactions between organisms in an ecosystem.

What is the link between food webs and food chains?

The link is that each path through a food web is a food chain. A food web connects all of the food chains in an ecosystem together.

What are keystone species?

They are species that are so crucial that a single change in their population causes dramatic changes in the structure of their ecosystem.

Define trophic level.

Each step in a food chain or food web

What always makes up the 1st trophic level?

Primary producers always make up the 1st trophic level while various consumers occupy every other level.

What do ecological pyramids show?

They show the relative amount of energy contained within each trophic level in a given food chain or food web

What are the 3 types of ecological pyramids?

Pyramids of energy, pyramids of biomass, and pyramids of numbers.

What is a pyramid of energy?

It is a diagram that shows an ecosystem's loss of energy, which results as energy passes through the ecosystem's food chain.

How much energy within one trophic level is transferred to the next trophic level?

About 10% of the energy available within one trophic level is transferred to the next trophic level.

Define biomass.

The total amount of living tissue within a given trophic level.

What do pyramids of biomass illustrate?

They illustrate the relative amount of living organic matter at each trophic level.

What do pyramids of numbers show?

They show the relative number of individual organisms at each trophic level.

What are the 2 main branches of biogeochemical cycles?

The water cycle and nutrient cycles.

What subtypes of nutrient cycles are there?

The carbon cycle, the nitrogen cycle, and the phosphorus cycle.

What is the 1st step of the carbon cycle?

The 1st step of the carbon cycle is that plants pull CO2 from the atmosphere.

What is the 2nd step of the carbon cycle?

The 2nd step of the carbon cycle is that animals eat the plants that pull CO2 from the atmosphere and release some CO2 by respiration.

What is the 3rd step of the carbon cycle?

The 3rd step of the carbon cycle is that animals eventually die, causing CO2 to return to the atmosphere after their bodies decompose.

What is the 4th step of the carbon cycle?

The 4th step of the carbon cycle is that some CO2 (from the carcasses of animals) ends up in deposits underground called fossil fuels.

Where is the largest single source of nitrogen?

It is in the atmosphere.

What is nitrogen an essential component of?

It is an essential component of DNA, RNA, and proteins.

What is one of nature's greatest ironies regarding nitrogen?

The irony is that although the majority of the air we breathe is nitrogen, most living organisms are unable to use nitrogen (as it exists in the atmosphere).

What is the 1st step of the nitrogen cycle?

The 1st step of the nitrogen cycle is that bacteria convert nitrogen gas into ammonia so plants can take in the nitrogen (nitrogen fixation).

What is the 2nd step of the nitrogen cycle?

The 2nd step of the nitrogen cycle is that consumers eat the producers (filled with nitrogen) and reuse nitrogen to make their own nitrogen-containing compounds. They also release some nitrogen as waste.

What is the 3rd step of the nitrogen cycle?

The 3rd step of the nitrogen cycle is that a small amount of nitrogen gas is converted to usable forms by lightning in a process called atmospheric nitrogen fixation.

What is the 4th step of the nitrogen cycle?

The 4th step of the nitrogen cycle is that humans add nitrogen to the biosphere through the manufacture and use of fertilizers.

What is the symbiotic relationship between bacteria and legume family plants?

The symbiotic relationship is that bacteria live in the roots of legume family plants and provide the plants with ammonia in exchange for the plant's carbon and a protected home.

What is the 1st step of the phosphorus cycle?

The 1st step of the phosphorus cycle is that weathering releases phosphorus from rocks.

What is the 2nd step of the phosphorus cycle?

The 2nd step of the phosphorus cycle is that plants bind phosphate into organic compounds from soil or water.

What is the 3rd step of the phosphorus cycle?

The 3rd step of the phosphorus cycle is that after plants bind phosphate into organic compounds, phosphate moves through the food web and the rest washes into bodies of water.