Populations and Communities

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Populations and Communities

• Living Things and the Environment

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A little vocab

• Ecology - the study of how organisms interact
  with their environment
• Organism - a living thing
• Habitat - the specific environment that provides
  the things an organism needs to live, grow, and
  reproduce

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Living or Nonliving?

• Biotic Factor - living parts of a habitat
• Examples - flowers, worm, frog
• Abiotic Factor - nonliving part of a habitat
• Examples - water, sunlight, oxygen

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The Line-Up

• Species - group of organisms that mate and
  reproduce
• Population - all members of one species in a
  particular area
• Community - all different populations that live
  in an area
• Ecosystem - a community including its surrounding
  environment (abiotic factors)

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Populations and Communities

• Studying Populations

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Types of Observations

• Direct Observation - counting all individuals by
  ones
• Indirect Observation - counting the signs of an
  individual

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Methods of Study

• Sampling - taking an estimate of a type of
  organism in an area
• Mark-and-Recapture Studies - catch an organism,
  mark it, then release

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Population Fluctuation

• Birth Rate - of births in a population during a
  specific time
• Death Rate - of deaths in a population during a
  specific time
• If birth rate is gt than death rate, then
  population is ____________
• If birth rate is lt than death rate, then
  population is ____________

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Population Fluctuation

• Immigration - organisms moving into a population
• Emigration - organisms moving out of a population
• Population Growth Equation
• (B - D) (I - E) N
• If N is a positive , the population is
  increasing

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Population Fluctuation

• Population Density - of individuals in a
  specific area
• Population Density Equation
• individuals
• Unit area

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Population Factors

• Limiting Factor - an environmental factor that
  causes a population to decrease
• Examples food and water, space and weather
• Carrying Capacity (K) - the largest population
  that an area can carry

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Populations and Communities

• Interactions Among Living Things

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The Theory

• Natural Selection individuals who have the best
  characteristics are more likely to survive and
  produce offspring
• Charles Darwin (1809 1882) father of
  evolutionary biology

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A Place in the World

• Adaptations a physical characteristic that
  helps an organism live in an area
• Example cacti in the desert
• Niche the role of an organism in its habitat,
  or how it makes its living
• type of food I eat
• Who else eats you
• Whether you need to survive

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The Fight

• Competition the struggle (fight) between two
  organism to get the same thing

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Lets Eat!

• Predation when one organism kills another for
  food
• Predator dominant organism
• Predator Adaptations help them catch and kill
  their prey
• Prey inferior organism
• Prey Defense Strategies certain adaptations to
  prevent being killed by predators
• Skunk, poison ivy, porcupines

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Relationships

• Mutualism both species benefit
• Example hippo and bird
• Commensalism one species benefits and the other
  is neither helped nor harmed
• Example clown fish and sea anemone
• Parasitism one species is benefited and the
  other is harmed. Doesnt kill because it needs
  the host to live
• Example head lice, ringworm, tape worm, ticks

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Relationship Species One Species Two
Mutualism
Commensalism O
Parasitism -
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Populations and Communities

• Changes in Communities

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Primary Succession

• Where no soil or organisms exist
• Example rocks after volcano erupts or glaciers
• Pioneer Species the very first organisms that
  inhabit an area
• How do they get there?
• wind, water, other organisms carry them
• What are they?
• Lichens and moss

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Secondary Succession

• A series of changes in an area where the
  ecosystem has been disturbed, but the soil and
  organisms still exist
• Example tornadoes, hurricanes, fires, logging,
  and farming
• Faster rate of succession

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Succession Diagram