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Plant adaptations to different growth conditions
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Core Standard:Observe, describe, and ask questions about structures of organisms that affect their growth and survival.______________________________________________________________
4.3.1 Observe and describe how offspring are very much, but not exactly, like their parents or one another.
4.3.2 Observe, compare, and record the physical characteristics of live plants or animals from widely different environments, and describe how each is adapted to its environment.
4.3.3 Design an investigation to explore how organisms meet some of their needs by responding to information from the environment.
4.3.4 Describe a way that a given plant or animal might adapt to changes as the result of human impact on the environment.
Oh the places you’ll grow: Plant adaptations to different growth conditions - where does it fit?
Process StandardsThe Nature of ScienceStudents gain scientific knowledge by observing the natural and constructed world, performing and evaluating investigations and communicating their findings. These principles should guide student work and be integrated into the curriculum along with the content standards on a daily basis.
• Make predictions and formulate testable questions• Design a fair test.• Plan and carry out investigations as a class, in small groups or
independently, often over a period of several class lessons.• Perform investigations using appropriate tools and technology that will
extend the senses.• Use measurement skills and apply appropriate units when collecting data.• estimate predictions with multiple trials.• Keep accurate records in a notebook during investigations and
communicate findings to others using graphs, charts, maps and models through oral and written reports.
• Identify simple patterns in data and propose explanations to account for the patterns.
• Compare the results of an investigation with the prediction.
Overview
• What all plants have in common....
• The major climate zones and plant adaptations to them
• A hands on exercise with insect-eating plants
What all plants have in common
• All plants require nutrients
• C, H, O, P, K, N, S, Ca, Fe, Mg
• Water, air, soil
• sunlight
Then why are there so many different plant species? Shouldn’t after time only one most competitive species
remain?
(See Hopkin’s cafe, mighty good!)
What plants differ in
• in nature plants differ in exactly what kinds of conditions they grow best in relative to their competitors
• And: plants differ in what other things they do that give different species unique advantages
• most plants grow in a much wider range of conditions (e.g. in botanical gardens) than we find them in nature, but this only works if we shield them from competition
Three major climate zones and the challenges (and opportunities)
they provide
We will focus on...
temperate zone
deserts
rain forest
temperate zone
deserts
But first some quick background:
We will focus on...
temperate zone
deserts
rain forest
temperate zone
deserts
4 questions for you: (1) Why do we have different climates as we move from equator to pole?
• The sun's rays hit the equator at a direct angle between 23 ° N and 23 °S latitude. Radiation is most intense here.
• As one moves north or south the rays arrive at an increasingly smaller angle to the surface and therefore the less intense the radiation.
We will focus on...
temperate zone
deserts
rain forest
temperate zone
deserts
(2) Why do we have the same climates on the northern and southern half of our planet?
• The intensity of the sun’s radiation decays similarly whether one moves north or south of the equator
4 questions for you:
But first some quick background:
We will focus on...
temperate zone
deserts
rain forest
temperate zone
deserts
(3) Why is Earth a bit like a rotisserie chicken?
Ehm, I mean what gives us seasons?
4 questions for you:
But first some quick background:
Another way of looking at seasonsEquinox Solstice
Last question
(4) Why do climate zones often still differ even though they are on the same latitude ?
Climate is not just affected by the intensity of radiation and seasonality but also by...• prevailing winds and
whether they bring moist warm air or cold dry air
• proximity to nearest ocean• the resulting precipitation
or lack thereof• barriers to clouds such as
mountain ranges• .....
OK, we are all set now: Three major climate zones and the
challenges (and opportunities) they provide
We will focus on...
temperate zone
deserts
rain forest
temperate zone
deserts
I. Rainforests and the tropical climate zoneWhat characterizes tropical climate and growth conditions?
I. Rainforests and the tropical climate zone
What characterizes tropical climate and growth conditions?
• warm; modest fluctuations between day and night• high humidity and much rain, during most/all parts of
the year (annual precipitation ~ 260 cm. (100 in.) in wet rain forests (but can go even higher)
• modest seasonality• little to no variation in day length throughout the year• water is generally abundant, in fact sometimes there
is way too much• sun light is reasonably abundant in higher strata but
not near ground level• tropical soil is poor in nutrients.....
II. Deserts and the arid climate zoneWhat characterizes desert climate and growth conditions?
• substantial daily temperature fluctuations, cold (but not freezing) to very hot
• extremely dry most of the year, low humidity, (annual precipitation: 0.25 cm (0.1 in) in Sahara; 7-30cm (3-12 in) in Sonoran desert).
• if rain than concentrated during brief parts of the year, then pronounced seasonality with a brief rainy season and a long dry season
• as a consequence sun light is over-abundant but water is (extremely) rare
• even in “rainy” deserts, rainy seasons may skip a year or 2 or 3...
II. Deserts and the arid climate zone
What characterizes desert climate and growth conditions?
III. Temperate climate zoneWhat characterizes temperate climate and growth conditions?
What characterizes temperate climate?
• significant daily temperature fluctuations• substantial seasonal temperature fluctuations
depending on region, e.g. 24C/43F for Great Basin region, 7C/12F for Mediterranean, 31C/56F for deciduous forests
• water availability fluctuates during the year but good at least during part of it
• annual precipitation <10 cm (4 in) in the driest regions to 50 cm (20 in) in the moister steppes and the mediterranean to 81 cm (32 in) in deciduous forests.
• but overall: winter = cold and dry season• soil quality is poor to extremely good
III. Temperate climate zone
Climate adaptation in real plants
Please examine the plants that are before you
Which climate might these plants be adapted to?
What features might allow them to cope particularly well with the climatic conditions in their respective habitat?
Please work as a group at each table and be prepared to present your results in a little while to the rest of us
I. List of plant adaptations to tropical climates
• large dark-green leaves (= lots of chlorophyll) to absorb sun light, especially in understory with lots of shade
• leaf arrangement maximizes light capture• slick waxy cuticle to allow rain to run off• shallow roots (no need to go deep for nitrogen or
water) and buttress or stilt roots (to help with stability)
• epiphytic life style (orchids, bromeliads, ferns, cacti etc) allows to be near sun light; soil not that great anyway, aerial roots instead
• many climbing plants (lianas, strangler figs, rattan, etc)
• continuous growth (no year-rings in trees); trees can reach enormous hights
• .....
II. List of plant adaptations to desert climates• Sun avoidance and tolerance; small leaves
or no leaves at all to minimize water loss• photosynthesis instead often in trunk• leaves frequently modied to spines which aid in
defense but also can reflect excess light• “accordion trunk” to reduce sun exposure• special CO2 capture mechanism (C4/CAM) to
minimize water loss while absorbing CO2
• highly reflective cuticle to reflect excess light• dense hair to generate isolating boundary layer• extremely seasonal growth and reproduction• long lived, must be able to skip years if seasons
don’t allow• succulence; storing of water in specialized
tissues (fleshy leaves, trunks, underground etc)• also extensive and deep root system
III. List of plant adaptations to temperate climates
• annual life cycle• deciduousness when perennial• if not deciduous then leafs are needles
protected by thick cuticle to survive winter• thick bark to protect against cold winters
The best way in Bloomington to survey up close the diversity of plant
adaptations to different climates is.....
The Jordan Hall GreenhousePublic Hours:M-F 7:30 am - 4:00 pmS&S 9:00 am - 3:00 pm
Group tours available by appointment:Phone: (812) 855-7717Email: [email protected] or through yours truly
Now on to a very special group of
plants –Carnivorous
plants!
Carnivorous plants – some background
Carnivory has evolved independently several times in diverse groups of plants
Carnivorous plants photosynthesize like regular plants, but they also catch insects (and sometimes larger animals)
If insects are withheld carnivorous plants can still grow but do less well
YOUR TASK: The plants before you are all carnivorous
Given what you know about insects and plants, please investigate the following questions
1) Why do they catch insects?2) How do they catch insects? 3) Once caught, what do they do with them?
Please form hypotheses that address these questions, and brainstorm about potential experimental tests.
We will ask you to share your progress and insightperiodically, and also provide you with some additionalinformation along the way, which may or may notfurther complicate your analysis
Additional information I
Many carnivorous plants lack the ability to digest insects!
(i.e. they can’t make the right enzymes)
Additional information II
The pitchers of many carnivorous plants are home to specialized
insects that do not get eaten by the plant
Additional information III
If these insects are removed the plant
does poorly, just like when you remove the
plant’s insect prey
1)Why do they catch insects and (3) once caught, what do they do with them?
Carnivorous plants generally grow in nitrogen poor environments, such as bogs. They supplement their nitrogen input through the digestion of insect prey. This digestion may be enabled by the plant’s own enzymes (venus fly trap) or the digestive abilities of bacteria and insects that co-inhabit pitchers.
2) How do they catch insects?• Many cool adaptations: pitcher plants often have nectaries on
edge of pitcher (attracts prey), slippery edge (facilitates capture), downward facing hair (impedes escape), and false window above pitcher (makes insects fly toward light but then bounce against lid).
• sundews have attractive but sticky droplets• bladderworts have touch-sensitive
underwater bladders that open and suck in prey
• venus fly trap has nectar glands inside trap and touch sensitive closing mechanism
But: Doesn’t all sort of non-food crap fall into the trap (like what?)?
One last task!Please investigate closely the venusfly traps before you and form one or more hypothesis as to if and how the trap might be able to distinguish between different objects, such as a water droplet, debris, or live insect.
Then brainstorm about possible experiments you could do to test your hypothesis.
Then present your hypothesis and experiment and see if we can do it!
Q: Can the trap tell the difference, and if so how
does it “know” when to close and when to stay
open?
Possible approaches
Q1: Can the trap distinguish between food and non-food?H1: yes it canH2: No it cannotTest: drop small stick vs live fly into trap; trap will close only for fly, H1 is supported
Q2: How does it distinguish? H1: must be edible H2: must be warmH3: must move.....Test: select appropriate contrasts
Q3: How is motion sensed?H1: prey bangs against wallH2: prey moves sensory hairs (once/multiple times?)H3: trap hears its prey scream.......Test: immitate appropriate behavior with forceps
Thank you!