Unit 1: the Science of Life

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• Unit 1 the Science of Life
• Ch. 2 Features of Life the Cell
• (selected sections)
• Ch. 30 Populations Communities
• (selected sections)

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WHAT IS BIOLOGY???
(living once living things)
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What do biologists study???

• Do they all study the same thing?
• yes no

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What is an organism?

• a complete living thing that carries out all life
  processes
• Organisms have 1 or more cells.

http//www.bigelow.org/bacteria/kingdom_2.jpg
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Living vs. Non-living

• How do we know?
• All living things must exhibit each of the
  characteristics of life.

http//www.animationlibrary.com/animation/18709/Do
lphin_in_frame/
http//www.animationlibrary.com/animation/25626/Fi
re_burns/
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Characteristics of Life

• 1. Living things are organized.
• What is the smallest (basic) unit of life?
• the cell
• What is the largest unit of organization?
• the biosphere
• the portion of earth that supports life (all life
  on earth)

complete living thing carrying out all life
processes
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Characteristics of Life

• 2. Living things respond to stimuli.
• What is a stimulus?
• a change in an organisms (internal or external)
  environment
• Why is responding to stimuli so important?
• can help an organism survive, stay safe, meet
  needs, etc.

Plants Responding to Light
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Characteristics of Life

• 3. Living things maintain homeostasis.
• What is homeostasis?
• ability of an organism/cell to maintain a
  constant internal environment (balance /
  equilibrium)
• examples
• body temperature too hot ? sweat, too cold ?
  shiver
• CO2 level in blood too high ? breathe faster

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Characteristics of Life

• 4. Living things grow develop.
• What is the difference?
• growth increase in size of organism due to
  increase in size or of cells
• development changes in form
• ex. from zygote (fertilized egg) to adult stage
  of life
• ex. from tadpole to frog

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Characteristics of Life

• 5. Living things reproduce.
• What is the goal of reproduction?
• make more organisms pass on genetic information
• What is the difference between asexual sexual
  reproduction?
• asexual
• 1 parent
• offspring genetically the same as parent each
  other
• sexual
• 2 parents
• offspring are genetically different from parents
  each other (combined DNA)

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Characteristics of Life

• 6. Living things have adaptations evolve.
• What is an adaptation?
• characteristic that makes an individual organism
  better able to survive in its environment
• Over time, beneficial adaptations are selected
  for the population or species evolves.
• Individual organisms do NOT evolve!!!

Explains the diversity of life
Pepper Moth Game http//www.techapps.net/interac
tives/pepperMoths.swf Principles of Natural
Selection "Interactive"
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Characteristics of Life

• 7. Living things need energy.
• How do organisms get energy?
• nutrition (make own food or eat)
• Why is (chemical) energy needed?
• metabolism
• all physical chemical processes in the body
  that convert or use energy
• ex. respiration, circulation, homeostasis,
  growth, reproduction, movement, digestion,
  excretion, nervous system function, etc.

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Where do organisms get energy?

• Almost all the energy organisms use comes
  from the sun!!!
• What type of organisms make their own food using
  the sun?
• producers (autotrophs)
• examples
• plants, phytoplankton
• What process do they use to make food (sugars)?
• photosynthesis

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Where do organisms get energy?

• What is the equation for photosynthesis?
• Where is the energy stored?
• in the chemical bonds between the atoms

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Where do organisms get energy?

• Some organisms can make their own food without
  sunlight by chemosynthesis.
• examples
• bacteria at hydrothermal vents

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Where do organisms get energy?

• What if an organism cant make its own food? How
  would it get energy/nutrition?
• It has to eat (ingest) food.
• What do we call organisms that have to eat to get
  energy?
• consumers/heterotrophs
• What do we call consumers that eat
• plants?
• herbivores
• other animals?
• carnivores
• both plants animals?
• omnivores

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Where do organisms get energy?

• In most organisms, what process releases the
  energy stored in the chemical bonds of food
  (glucose)?
• What materials are needed?
• What is given off?
• some waste heat

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Where do organisms get energy?

• cellular respiration
• What is the equation?
• What other equation does it look like?
• photosynthesis
• What do organisms use the energy for?
• life functions (metabolism)

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Where do organisms get energy?
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Energy Nutrients

• Can energy be recycled (in the same form)?
• NO!!!! It can only be transferred transformed
• usually given off as heat

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Energy Nutrients

• Can nutrients be recycled?
• yes
• Why must nutrients be recycled?
• so that they can be put back into the soil used
  again by other organisms (usually autotrophs)

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Where do organisms get energy?

• What type of organisms recycle nutrients (back
  into the soil)?
• special types of heterotrophs
• detritivores
• eat dead organisms
• ex. crabs, worms, snails
• decomposers
• break down organic waste (poop)
• ex. fungi bacteria

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Energy Flow Food Chains
Where do almost all communities get their energy?

• Does energy only flow through individual
  organisms?
• No energy also flows through communities.
• shown by food chains

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Energy Flow Food Chains
5th trophic level
4th trophic level
3rd trophic level
2nd trophic level
Trophic level step in the food chain
1st trophic level
http//www.cnr.vt.edu/forsite/owlpellet/josh/PICTS
/foodchain.jpg
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Food Chains Food Webs

• food chain ? just one path of energy
• food web ? most/all possible paths of energy

Food Web Interactive
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Energy Flow Food Webs
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What occurs as energy is passed to each trophic
level?

• there is less energy available to be passed on

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Energy Flow Energy Pyramids

• The 10 Rule of Ecological Efficiency
• 10 energy is passed to next level
• 90 lost
• some lost b/c used by original organism for its
  life processes
• most lost as heat
• Energy can NOT be recycled,
  only transferred or
  transformed.