Biology : Ch. 15 : Ecology Populations

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Biology Ch. 15 Ecology (Populations)

• Our next unit of study will be Ecology.
• Ecology is the study of interactions between
  animals and their environment.

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Population

• A population is described as individuals of a
  species that live together and naturally
  reproduce.

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Journal Activity 1

• Identify a local population. Explain its range
  and habitat.

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Population Features

• The number of individuals in a population is its
  size.
• The number of individuals living in a given area
  is the density.
• The arrangement of individuals in a population is
  called its dispersion.

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Population Growth

• Populations grow in an exponential manner.
• The population size that an environment can
  sustain is called the carrying capacity.(K)

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Population Control

• Populations are controlled by the resources
  available food, water.
• These resources which control populations are
  termed density dependent factors.

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Population Control

• Other factors such as weather and climate control
  populations. These are called density independent
  factors.

Mosquitoes
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Population Growth

• Some species show rapid population growth
  (r-strategists) insects, etc.
• Other species show slow growth.(K-strategists)

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Journal Activity 2

• Identify the following as r or K strategist
  species.
• cats
• humans
• rabbits
• mayflies
• grasses

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15-2 How Populations Evolve

• Populations change over time by a change in the
  frequency of alleles and genes.
• Natural selection is thought to be the force
  which drives this change in alleles and genes
  in a population.

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Hardy Weinberg Principle

• This principle states that the allele frequency
  in a population doesnt change unless acted upon
  by an outside process. (Natural Selection)

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Evolutionary Forces

• There are thought to be 5 evolutionary forces
• Gene flow
• Nonrandom mating
• Genetic drift
• Natural selection
• mutation

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Evolutionary Forces

• Gene flow the movement of alleles into or out of
  a population
• Mutation a change in DNA
• Nonrandom mating preferences based upon a
  phenotype or behavior

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Evolutionary Forces

• Genetic Drift changes in a population based upon
  a chance event.(usually small populations)
• Natural Selection selection of genes by the
  environment which cause greater survival and
  reproduction

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Gene Persistance

• Some genes persist due to carriers.
• Harmful genes can cause death when an individual
  is homozygous, but being heterozygous keeps the
  allele alive in a population.

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Ch. 16 Ecosystems

• The environment is described as the surroundings
  (living and non-living) of an organism.
• The living factors in an environment are termed
  biotic.
• The nonliving factors in an environment are
  termed abiotic.
• The biosphere is portion of earth which supports
  life.

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Journal Activity 1

• In your journal titled Activity 1, make a data
  table such as the one below. Identify 5 biotic
  and 5 abiotic factors in your environment and
  describe the influence of six of these.
• Biotic Abiotic
• _____________________ _________________
• _____________________ _________________
• _____________________ _________________
• _____________________ _________________
• _____________________ _________________

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Journal Activity 1 Cont

• Factor Influence on Your Life
• _________ ___________________________
• _________ ___________________________
• _________ ___________________________
• _________ ___________________________
• _________ ___________________________
• _________ ___________________________

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Organization of Life Levels

• Biosphere
• Ecosystems
• Communities
• Populations
• Organism

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Ecosystems

• All biotic and abiotic factors in an area form an
  ecosystem.
• Ecologists focus on ecosystem stability.

Marine ecosystem
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Communities

• Communities may be defined as several interacting
  populations which share their an area.
• Communities include several different species of
  animals, plants, etc.

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Populations

• A population is described as a group of organisms
  of one species living in the same place at the
  same time, which can interbreed.

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Organism

• An organism is an individual. The behavior of an
  organism is often studied in ecology.
• Daily movement, feeding, and breeding behavior
  may be the topic of study of an organism.

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Organization of Life Summary

• In ecology, many organisms make up a population,
  many populations make up a community, an
  ecosystem is a community with the environment,
  and the biosphere is the total of all ecosystems
  on earth.
• Organism-- Population -Community--Ecosystem--Bios
  phere

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Journal Activity 2

• In your journal titled Activity 2 describe the
  following
• 1) Identify a local ecosystem
• 2) Identify 10 different animals and 5 different
  plants in this community.
• 3) Identify and describe the effect of 3
  different abiotic and biotic factors on this
  ecosystem.

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Niche/Habitat

• A niche is the role that a species plays in
  their community.
• A habitat is the place where an organism lives
  out its life.

Local Turkey Buzzard
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Journal Activity 3

• In your journal make a table as shown below.
  Describe the niche and habitat of the species
  listed
• Species Habitat Niche
• Blacktail deer ___________ _____________
• Skunk ___________ _____________
• Spiders ___________ _____________
• Mice ___________ _____________
• Canadian Goose ___________ _____________
• You ___________ _____________

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16-2 Energy Flow in an Ecosystem

• Organisms interact with each other in a variety
  of ways.
• These interactions allow for organisms to obtain
  energy, and control populations of species.
• The method in which organisms obtain energy is
  important in studying ecology.

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Obtaining Energy

• Autotrophs organisms that use energy from the
  sun to make their food. (plants)
• Heterotrophs organisms which depend upon
  autotrophs as their food or energy
  source.(animals)

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Heterotrophs

• Heterotrophs are classified into other categories
  based upon their feeding habits.
• Heterotrophs include the following
• Carnivores
• Scavengers
• Omnivores
• Decomposers

How am I classified?
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Carnivores

• Carnivores animals that kill and eat other
  animals or heterotrophs.
• List some carnivores

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Scavengers

• Scavengers animals which dont kill their food,
  but feed on dead animals.
• List some scavengers

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Omnivores

• Omnivores animals which eat both plants and
  animals.
• Examples
• Humans
• Racoons
• Coyotes
• Bears

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Decomposers

• Decomposers organisms which break down compounds
  of dead plants and animals.
• Examples bacteria, fungus, protists

Fungi are decomposers
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Journal Activity 4

• Using your resources to complete the following
  activity.
• Make a list of 10 different animals found in the
  wetlands around Dayton, and two different plants.
• Use the internet and other sources to identify
  each animal as to their feeding method
  (carnivore, omnivore, scavenger, decomposer)
• Construct a simple feeding pyramid of the plants
  and animals. (5pts)

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Feeding Pyramid Example
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Interactions of Organisms

• While the predator-prey interaction of organisms
  is obvious, there are other interactions
  involving organisms.
• Some organisms of different species form
  permanent associations. These relationships are
  known as symbiosis.

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Symbiosis

• There are three different categories of
  symbiosis.
• Commensalism one species benefits, while the
  other isnt harmed or benefited. Ex.) moss on
  trees

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Symbiosis

• Mutualism a type of symbiosis in which both
  organisms are benefited.
• Ex.) Lichen an algae and a fungus.

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Symbiosis

• Parasitism a type of symbiosis in which one
  member is benefited, while the other is harmed.
• Ex.) tapeworms, roundworms, etc.

Tapeworm
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Journal Activity 5

• Use your resources to identify an example of each
  type of symbiosis discussed mutualism,
  commensalism, and parasitism. For each type of
  symbiosis include the following
• A) Identification of the two different species
  and the type of symbiosis.
• B) A brief description of the relation between
  the two.

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Matter and Energy in Ecosystems

• Energy moves through an ecosystem in a complex
  way.
• In studying the overall health of an ecosystem it
  is essential to study the matter and energy
  changes and interactions in an ecosystem.
• Food chains, food webs, and food pyramids are
  tools used to study matter and energy in
  ecosystems

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Food Chains

• Food chains are typically a simple model which
  uses arrows to show the movement of matter and
  energy in an ecosystem.

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Trophic Levels

• Trophic levels are used to study matter and
  energy in an ecosystem.
• A trophic level is described as a feeding step of
  an organism.

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Trophic Levels

• Producers (plants or autotrophs) are assigned
  trophic level 1
• First order consumers animals which feed
  directly on the producers are trophic level 2
• Second order consumers animals which feed on
  other animals (carnivores) are listed as trophic
  level 3

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Trophic Levels

• Tertiary consumer animal which feed on second
  order consumers, trophic level 4.
• Ex.) Sharks, Humans, Bears, etc.

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Journal Activity 6

• In your journal construct a food chain, food web,
  or pyramid for the following members in an
  ecosystem. Identify the trophic levels. (5pts)
• Animals mice, rabbits, raccoon, deer, cougar,
  bear, quail, bobcat, grasshoppers, snake
• Plants rye grass, blackberries, seeds

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Energy Flow in an Ecosystem

• As you go up a food pyramid you find that the
  energy in an ecosystem greatly decreases.
• There is much more energy in trophic level 1 than
  in trophic level 2 , etc.
• Explain why energy decreases as you go up trophic
  levels?

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Ecological Pyramids

• Ecological pyramids can be constructed to compare
  populations and energy amounts of trophic levels.
• In an ecological pyramid the 1st trophic level is
  on the bottom, and the size of the step
  represents the amount of the population or
  energy, or factor being studied.

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Cycling of Material in an Ecosystem

• Important nutrients, and energy is cycled in
  ecosystems.
• Water cycle
• Carbon cycle
• Nitrogen cycle

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Cycles

• Water, carbon, and nitrogen cycles allow for the
  recycling of key elements in an ecosystem.
• Bacteria and other organisms play an important
  role in the cycling of nutrients in an ecosystem.

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Journal Activity7

• Identify a cycle you will describe. ( water,
  nitrogen, carbon, other)
• Using the internet find a good diagram of the
  cycle to copy and paste to a word document.
• Give a detailed description of the cycle, and the
  different stages of the cycle.
• Describe the importance of this cycle to the
  cycling of nutrients in an ecosystem.