Diversity and Interdependence of Life

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Diversity and Interdependence of Life
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Speciation

• We have learned that evolution is the process of
  DNA mutations creating new species over time.
• What determines if different organisms are
  different species? What is a species?
• A species consists of all individuals that can
  breed together and produce fertile offspring.
• This definition is called the Biological Species
  Concept.

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A female donkey mated to a male horse produces
what?
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A mule (which is sterile) Hence, donkeys and
horses are separate species.
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Criticisms of the Biological Species Concept

• Cannot be used with asexual organisms (bacteria).
• Cannot tell if fossil specimens were capable of
  interbreeding.
• Doesnt account for isolation
• Behavioral isolation having different courtship
  rituals or behaviors
• Geographic isolation separated by geographic
  barriers
• Temporal isolation reproduce at different times

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How are different species named?

• Taxonomy- The science of naming and classifying
  organisms.
• A Swedish biologist named Carolus Linnaus came up
  with a two-word system for naming organisms. It
  is called binomial nomenclature.
• There are 7 levels of classification
• Kingdom-Phylum-Class-Order-Family-Genus-Species
• In binomial nomenclature, the first word is the
  organisms genus name and the second word is the
  species name.

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Human Classification

• Kingdom Animalia
• Phylum Chordata
• Class Mammalia
• Order Primate
• Family Hominidae
• Genus Homo
• Species Sapien (means wise)
• Using binomial nomenclature, we are Homo sapiens.
  Always capitalize the genus and italicize or
  underline both the genus and species names.

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The levels get more specific as you work down
to the species.
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Have all living things been classified?

• NO! Our knowledge of all living things is
  limited.
• Classification is based on anatomy, embryology,
  DNA, behavior, and when the organism evolved.
• If you are unsure of the binomial nomenclature of
  an organism, you can use an identification system
  called a dichotomous key.

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Example of a Dichotomous Key
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Interdependence of Life

• Ecology- The study of relationships between
  living things and their environment.
• Biosphere- The area around the earth where life
  exists.
• includes the hydrosphere, lithosphere, and
  atmosphere

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Levels of the Biosphere

• Biome- a large area characterized by certain
  animal and plant species as well as climate
• Ecosystem- All of the living and non-living
  components of a particular geographic area.
• Community- A naturally occurring group of plants
  and animals living in a particular area.
• Population- A group of organisms of one type
  (species) living in a particular area.
• Habitat- The physical area in which an organism
  lives.
• Climate- The prevailing weather conditions of a
  geographic area.

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Levels of a Biosphere
BIOSPHERE
POPULATION
BIOME
ECOSYSTEM
COMMUNITY
NON-LIVING COMPONENT (Habitat and Climate)
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Components of an Ecosystem

• Abiotic- Non-living Components
• Sunlight
• Temperature
• Soil
• Soil chemistry
• Precipitation
• Rocks
• Erosion

• Biotic Living Components
• Plants
• Animals
• Fungus
• Bacteria
• Protists

Where do viruses belong?
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Trophic Levels of Ecosystems

• A trophic level is a feeding level.
• The relationship between what an organism eats
  and what eats it.
• Where it fits into a food chain/web
• The 1st Trophic Level is at the bottom of the
  food chain.

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How Biotic Factors Obtain Energy

• Producer (Autotroph)
• Organisms that can make their own food organic
  (carbon containing) materials
• At the 1st Trophic Level
• Examples plants and bacteria
• Photosynthetic- Use energy from sunlight and
  convert it into organic energy
• Chemosynthetic- Use energy from inorganic
  compounds and covert it into organic energy

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• Consumer (Heterotroph)
• Organisms that cannot make their own food and
  must get it from an external source.
• Primary (1st) consumer- herbivore- eats only
  producers
• Secondary (2nd) consumer- carnivore- eats only
  consumers
• Tertiary (3rd), quaternary (4th), etc.
• Omnivore- eats producers and consumers
• Detritivore- breaks down wastes and dead bodies
• Decomposer- fungi, bacteria return nutrients to
  the soil for absorption

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Food Chain

• Food Chain Specific feeding sequence in which
  organisms obtain energy in an ecosystem
• Grass ? Caterpillar ? Sparrow ? Snake ?
  Coyote
• Arrows always point in the direction of energy
  flow!
• Food Web Interrelated food chains

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• FOOD WEB
• What is/are the producer(s)?
• What is a herbivore?
• What is a primary consumer?
• What is a secondary consumer?
• What is a tertiary consumer?
• What would be 3 consequences in the fish
  population died out?

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How do we keep track of energy in ecosystems?

• Ecological Pyramids- A diagram that shows the
  amounts of energy at each trophic level in a food
  chain or food web. (3 types)
• 1. Numbers Pyramid counts the of individuals
  (does not discriminate by size) can be an
  inaccurate indicator of energy at that level
• Ex. Caterpillars outnumber the trees that they
  feed on
• 2. Biomass Pyramid measures amount of living
  tissue (dry weight) in grams
• 3. Energy Pyramid measures amount of energy
  stored in tissues (ex. fats 9 Cal/gram
• carbohydrates/proteins 4 Cal/gram)

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Numbers Pyramid
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Biomass Pyramid
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Energy Pyramid
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Energy Transfer

• Amount of energy available to do work decreases
  as energy passes through a system
• 10 transfer of energy (90 energy lost) from one
  level to the next. Most is lost to the air as
  heat.
• How much energy would be transferred to each
  level of the following food chain?
• Grass?Caterpillar?Sparrow ?Snake ?Coyote
• 1200 kcal ? ? ? ?

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Population Size

• Studying changes in population size is called
  population ecology.
• This helps scientists predict future changes in
  populations and better understand how to conserve
  biodiversity.
• Counting members of a population is often
  impossible. Estimation of population size can
  calculated using the Capture-Recapture Method.

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Capture-Recapture Method

• In the Capture-Recapture Method, a sample of
  animals are caught and tagged. They are then
  released back into their habitat. Other samples
  are then captured at various times and each time
  the total number and marked number of animals are
  noted.
• The following equation is then used to estimate
  population size.
• N originally marked x total animals
  captured
• of animals marked that were
  captured

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• 20 fish were captured, marked and put back into a
  pond. On 10 different occasions, samples were
  taken from the pond. What is the estimated
  population size?

obtained in the sample marked in the sample
15 2
12 4
18 0
22 2
12 1
16 1
13 3
11 4
16 2
20 2
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How do populations grow?

• Most populations grow either exponentially or
  logistically.
• Exponential growth occurs when resources are
  plentiful and the reproduction rate is greater
  than the death rate.
• On a graph, exponential growth looks like a J.

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How do populations grow?

• Logistic growth occurs if there are limited
  resources and growth of the population begins to
  slow as competition for those resources
  increases. The growth of the population
  eventually slows to nearly zero as the population
  reaches the carrying capacity for the
  environment.
• On a graph, logistic growth looks like a S.

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