Post on 07-Jan-2016
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Lecture 1: Intro to Plants, Intro to Science
Why do we love plants? What makes them so special?
Plants are:
People and Plants
We affect each other. – how?»We can’t live without them!».».
»They can destroy habitat, harming our economy – invasive plants!!
»We can alter the course of their evolution, through:–Gm crops, conservation genetics, selective
breeding
Plants are sources of
food paper fibers Medicine Chocolate Sugar vanilla cinnamon
•pepper
•wood
•cotton
•linen
•roses
•paper
•oxygen
THE PROCESS OF SCIENCE
The word science is derived from a Latin verb meaning “to know”
» Science is a way of knowing» .
The Process of Science: "The Scientific Method"
Communicate results
Test the hypothesis
Develop one or more testable hypotheses
Ask Questions about what you see
Observe the Natural World
What’s a Scientific Question?
Scientific Questions are….
What’s a Hypothesis?
Tentative, but untested explanations» Ex.
Make predictions that can be tested» Predictions written as “If [hypothesis], then……”
statements » .tree to grow taller
How do you test a Hypothesis?
Via controlled experiments or pertinent observations» All variables must be controlled
Kinds of variables:» Independent variable –
» Dependent variable –
» Controlled Variables - All other things (variables) that you try to hold constant
Experiments of classical design
Individuals studied divided into two groups» Experimental group
» Control group –exposed to the identical conditions as
the experimental group, but not be exposed to the independent variable
What happens if all of our experiments fail to disprove our hypothesis?
What if workers in other parts of the community, county, state, country, or world also fail to disprove your hypothesis?
Theory
We arrive at theories by scientific method
To Prove or Not to Prove
Experimentation can either support or reject a hypothesis.
Experimentation can never prove a hypothesis 100% correct. – why?
After each each experiment we need to re-evaluate our results and observations to either make changes in our hypothesis or more likely design a new experiment.
Which end of a plant is up?
Cells
Tissues
Organs
Systems
Muscle cell
Muscle tissue
Heart
Circulatory system
Parenchyma cell
Dermal tissue
Leaves
Shoot system
Three organs: Roots, stems, leaves
1. Roots–
• Covered with root hairs – increased surface area for absorption
Modified Roots –
Prop roots
Sweet Potato – storage root
Aerial strangler roots
Pneumatophores
Buttress roots
2. Stems/shoots
Two types of shoots
1. Vegetative –
2. Reproductive – Two parts of stem:
1. Node – point of leaf attachment
2. Internode – stem segments between nodes
Two types of buds1. Terminal bud –
2. Axillary buds – in angle (axil) between leaf & branch, contain meristem with potential to become a vegetative shoot. Mostly dormant.
Apical dominance =
-remove or depress apical bud, axillary buds begin to grow.
Modified Shoots (stems):
Stolons –
Rhizomes –
Bulbs – swollen underground shoots
Tubers – swollen rhizomes
Asexual, vegetative propagation
Stores food for later growth
3. Leaves – main photosynthesis organs
http://www.knotweed.co.uk/japknot_Info.htm
Modified leaves
Compound, doubly compound – why??
Modified leaves
Leaf types:
Simple leaf =
Compound leaf = divided into distinct units called leaflets
Four types of leaf arrangement:
1. Acaulescent –
2. Alternate –
3. Opposite – leaves borne across from each other at the same node
4. Whorled – 3 or more leaves arising from the same node.
3Each male flower part is called a stamen.
The stamen is composed of:1. Filament –
2. Anther – a collection of pollen sacs that sits on top of the filament.
Each female part is called a pistil.
Pistil = the female reproductive organ, consisting of:1. Stigma –
2. Style –
3. Ovary – the base of the pistil, contains the ovules. (Mature ovules are seeds and mature ovary is the fruit)
More terms!!!Complete flower =
Incomplete flower = lacks one of the above parts
Fruit types
Fruit =
*the primary function of a fruit is seed dispersal