announcements
Download
Skip this Video
Download Presentation
Announcements

Loading in 2 Seconds...

play fullscreen
1 / 25

Announcements - PowerPoint PPT Presentation


  • 58 Views
  • Uploaded on

Announcements. Next week: THANKSGIVING, NO CLASS! Work on Group Project Presentation (p170—checklist p 171-172) In 2 weeks, Functional Response Lab. Today’s Objectives. Examine examples of adaptation & convergent evolution in the greenhouse

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Announcements' - irina


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
announcements
Announcements
  • Next week: THANKSGIVING, NO CLASS!
  • Work on Group Project Presentation (p170—checklist p 171-172)
  • In 2 weeks, Functional Response Lab
today s objectives
Today’s Objectives
  • Examine examples of adaptation & convergent evolution in the greenhouse
  • Explore the relationship between stomata density and climate—a study of adaptation?
  • Consider how adaptations are studied and the link between ecology and evolution
adaptation
Adaptation

Heritable characteristic that improves organism’s fitness (survival & reproduction)

Schemske et al.

why do organisms match their environment

fitness

adaptation

Why do organisms ‘match’ their environment?
  • the ‘match’ is genetic
  • the ‘match’ is induced by environment

Natural selection:

differential survival and reproduction of individuals

based on genetic differences in some trait(s)

adaptation1
Adaptation
  • Any heritable characteristic of an organism that improves its ability to survive and reproduce in its environment.
  • Also used to describe the process of genetic change within a population, as influenced by natural selection.
adaptation acclimation
Adaptation ≠ Acclimation
  • Acclimation
    • individual changes over short period of time to survive better in environment
    • Ex: shed winter fur in summer
  • Adaptation
    • a population evolves to be better suited to its environment via natural selection & genetic change over multiple generations
    • Ex: evolution of cryptic coloring to avoid predation

flickr

natural selection
Natural Selection
  • Selection acts on phenotypes
    • If brown beetles are less visible to predators than green beetles
    • Then brown beetles will be more likely to survive & reproduce
  • Evidence is seen in populations over generations
natural selection key points
Natural selection – key points

differential survival and reproduction of individuals

based on genetic differences in some trait(s)

  • For adaptations to evolve:
  • - differences in the trait must cause differences in
  • fitness
  • - differences in the trait must be heritable
  • Fitness depends on the environment.
  • local adaptation
ecology evolution are interconnected
Ecology & Evolution are interconnected
  • Ecology
    • study of interactions between organisms and their environments
  • Adaptation
    • An evolved characteristic of an organism that improves its fitness in its environment
  • Thus, adaptations are both ecological & evolutionary
rainforest ecology
RainforestEcology
  • Light competition
  • Lots of rain
    • Promotes fungal growth
  • High biodiversity
  • Adaptations include
    • Epiphytes, vines, leaf morphologies
desert ecology
DesertEcology
  • Water limited
  • Temperature extremes
  • Adaptations include
    • CAM, annual life cycle, water storage
stomata
Stomata
  • Trade-off between staying open and obtaining CO2, and staying closed to reduce water loss
  • Structures on the outer layer of plants
  • “Mouth” in Greek
  • Allow gases such as carbon dioxide, water vapor and oxygen to move rapidly into and out
slide14

Stomata density varies across plant species and habitats

http://www.scienceclarified.com/Io-Ma/Leaf.html

http://radio-weblogs.com/0105910//2004/01/22.html

http://www.microscopy-uk.org.uk/micropolitan/botany/frame1e.html

stomata study
Stomata study
  • 1. Choose a plant in the greenhouse or outside. Apply an even, thin layer of clear nail polish on to the underside of the leaf surface.
  • 2. Wait till the polish dries completely.
  • 3. Gently lift the sides to peel off the nail polish without tearing it.
  • 4. Place the peeled layer onto a slide (without any creases).
  • 5. Observe under a 10 or 40x lens and count the number of stomata. If the number of stomata is too numerous to count, just count a portion of the field of view and multiply the results accordingly.
  • 6. Calculate stomatal densities per cm2.
slide tips and greenhouse use
Slide tips and greenhouse use
  • Stay on path and be respectful of plants
  • Use plant tips, or herbivore-attacked leaves
  • AVOID—small plants, healthy, centrally-located leaves, and Wellwichia
  • Do not choose fuzzy or moist leaves—nail polish does not come off
at greenhouse
At Greenhouse
  • IN PAIRS: Use worksheet (pg 140) to tour greenhouse & identify different adaptations
  • Find examples of 10 adaptations on sheet
  • INDIVIDUALLY: Make a stomata slide from a species you can identify. Your group must have at least one rep from desert, temperate, and rainforest habitats

TAKE: p 140, a pencil, nailpolish

find stomata densities
Find stomata densities
  • Count all you see in a field at either 10x or 40x
  • Divide your stomata number by the approximate area of your field (for either 10x or 40x)
  • Look up average temperature, rainfall, humidity?, etc. of your plant’s habitat
  • Put all information on the board
while you wait
While you wait
  • Answer the questions on the handout.
  • For question 2, read up on an adaptation you think is interesting (but not that we have discussed) using the web. Consider using You-Tube.
how do we know if a trait gradient is caused by a local adaptation
How do we know if a trait gradient is caused by a local adaptation?
  • Trait variation across the gradient is greater than variation within the gradient
  • Observed trait variation has a genetic basis
  • Trait variation must have evolved in that location, and not be from an already different founder population
  • Variation must have an effect on survival in that habitat
slide21

Dry

Wet

habitat:

Testing for local adaptation

Observation: differences in stomata density is correlated with humidity and temperature

morph:

How can we test whether the difference in stomatal density

is an adaptation? What other explanations are possible?

slide22

Testing for adaptation:

reciprocal transplant experiment

Dry Habitat

Wet Habitat

effective

predators

slide23

Prediction

Plant Fitness

Wet

Dry

Habitat

slide24

If we see this pattern….

  • Stomata density is likely to be an adaptive trait.
      • Plants with LOW stomatal density have high fitness at DRY habitat
      • Plants with HIGH stomatal density have high fitness at WET habitat
wrap up the study
Wrap-up the study
  • IN PAIRS Use the info on the board. On a new sheet of paper, make either 1 bar graph of the mean stomata densities and standard errors from each climate AND 1 bar graph of the % closed in each climate OR make line graphs comparing the 3 climate variables to stomata densities.
  • Answer these questions on your separate sheet:
  • Using class data, do you think your prediction was right? Why?
  • What is one flaw of this study?
  • Could a study like this one conclusively show stomata densities are the result of a local adaptation? Explain.
  • Do you think plants grown in a greenhouse would have different #s of stomata than the same species in nature? If yes, does this support or refute the idea that s. densities are adaptive? Explain.
ad