Ecology Study Guide

  1. Describe the levels of organization in ecology:

Organism / Individual
Population / A group of individuals that belong to the same species and live in the same area
Community / Groups of different populations (different species) that live in the same area
Ecosystem / All the organisms that live together in one area and the physical (non-living) elements of the area as well.
  1. What are trophic levels? What percentage of energy is passed from one trophic level to the next?

Trophic levels – steps in a food chain or food web

10% of energy is passed up to the next trophic level

Most energy is lost as heat

  1. What are biotic and abiotic factors? Give examples of each.

Biotic – living things – plants, animals, fungi, bacteria

Abiotic – non-living things – rocks, wind, sunlight

  1. What is the difference between how energy moves through an ecosystem and how matter moves through an ecosystem?

Matter cycles and is reused over and over, energy only moves in one direction and much is lost at each trophic level

  1. What is a niche? What is competitive exclusion?

Niche – an organisms way of life and use of its environment – where it lives, what it eats, predators, space, amount of light, etc.

Competitive Exclusion – only one population can occupy a niche. When two populations compete for the same niche, one of them will prevail and the other will, die out.

  1. What is the difference between primary and secondary succession?

Primary succession occurs when there are absolutely no remnants of the previous community remaining.

Secondary succession is when some remnants of the previous community remain (small trees, some vegetation, nutrients in soil)

  1. What is the difference between a food chain and a food web?

A food chain is a series of eating relationships from one population to the next.

A food web is a network of many interconnected feeding relationships.

Description / Example
Primary producer / Uses energy from the sun to create its own food / Plants, algae
Carnivore / An animal that eats other animals / Lion
Herbivore / An animal that eats plants / Rabbit
Omnivore / An animal that eats plants and animals / Bear
Decomposer / Breaks down decaying matter into detritus / Fungi
Detritovore / Eats detritis / Worms
Scavenger / Eats remains of dead animals killed by carnivores / Vulture
  1. Describe the water cycle.

Surface water (for example from the ocean) evaporates (turns from liquid to vapor) into the atmosphere where it forms clouds. Precipitation occurs when it rains and the water vapor condenses back into liquid and fall to the earth. From there it can either run into the ocean or percolate into the ground to become groundwater.

  1. Describe the carbon cycle.

Carbon dioxide is absorbed in producers through the process of photosynthesis creating high energy sugars. Consumers eat the producers to absorb the carbon. Producers and consumers release carbon dioxide back to the atmosphere through cellular respiration. Stored carbon (fossil fuels) can be burned (combustion) and release carbon dioxide back to the atmosphere

  1. Describe a simplified nitrogen cycle (focus on nitrogen fixation and denitrification)

Nitrogen fixation makes atmospheric nitrogen into usable nitrogen in the soil through bacteria. Denitrification is turning usable nitrogen back into atmospheric nitrogen through bacteria

Definition
Mutualism / Benefits both organisms
Parasitism / Benefits one organism, harms the other
Commensalism / Benefits one organism, does not harm or help the other
  1. Differentiate between climate and weather.

Climate is long term trend in precipitation and temperature for a region.

Weather is daily fluctuations in temperature/precipitation for a region

  1. What is the greenhouse effect?

natural phenomenon that maintains Earth’s temperature range

  1. Autotroph vs. heterotroph

Autotroph – organism that generates its own food energy

Hetertroph – organism that needs to consume another organism for food energy

  1. What source supplies the energy needed to run photosynthesis?

Sunlight

  1. Where does photosynthesis take place (include locations of light dependent and light independent reactions)?

Chloroplast

Light dependent – thylakoid membrane in the chloroplast

Light independent – stroma of the chloroplast

  1. What is needed to start photosynthesis and what products come out?

Carbon dioxide and water to start

Oxygen and glucose (high energy sugar) as a product

  1. What source supplies the energy needed to run cell respiration?

Glucose (high energy sugars)/ food

  1. Where does cell respiration take place (include locations of glycolysis, kreb’s cycle and electron transport chain)?

Glycolysis – cytoplasm of a eukaryotic cell

Kreb’sCycle - in the matrix of the mitochondria

Electron Transport Chain – inner membrane of the mitochondria (or cristae)

  1. What is needed to start cell respiration and what products come out?

Glucose (high energy sugars) and oxygen to start

Carbon dioxide and water and products

  1. Define
  2. Density dependent vs. independent factors

Density dependent: affects populations significantly when population size increases

Density Independent: affects all populations no matter their size (think natural phenomenon)

  1. Limiting factor: factors that control the growth of a population and determine the carrying capacity
  2. Immigration/Emigration

Immigration: organisms moving Into a community

Emigration: organisms EXTING a community

  1. Carrying Capacity: the maximum number of individuals of a species that a particular environment can support
  1. When does a population grow exponentially vs. logistically?

Exponentially (J curve): lots of available resources (food, water, shelter), low predation, low disease. Birth and Immigration rate is more than Death and Emigration rate

Logistically (S curve): after exponential growth predation increases, disease increases, resources becoming scarcer. Birth/Immigration rate equals Death/Emigration Rate

  1. Draw two graphs one showing exponential growth and the other logistic.

  1. What may cause a population to increase? Decrease? Stay the same? (hint: discuss birth/death rate, emigration/immigration, discuss resource availability also)

Increase: Lots of resources, low predation, low disease (birth/immigration greater than death/emigration)

Decrease: lots of predation, lots of disease, reducing resources (birth/immigration less than death/emigration)

Same: Enough resources for a stable population, enough predator-prey relationships, some disease but not enough for mass die off (birth/immigration = death/emigration)

  1. Give examples of density-dependent and density-independent limiting factors.

DD: competition, predation, parasitism and disease, shelter, food availability

DI: unusual weather, natural disasters