Introduction: Themes in the Study of Life€¦ · Biological Themes! Feedback Mechanisms Regulate...
Transcript of Introduction: Themes in the Study of Life€¦ · Biological Themes! Feedback Mechanisms Regulate...
Introduction: Themes in the Study of Life Chapter 1 AP Biology
Warm Up l Please complete the pretest that you picked
up when you came in.
Inquiring About Life l Biology- the scientific study of life.
Biological Themes l New Properties Emerge at Each Level in
the Biological Hierarchy l Life Emergent Properties
l Regulation l Order l Energy Processing l Evolutionary Adaptation l Reproduction l Growth and Development l Response to the Environment
Biological Themes
l Organisms Interact with Other Organisms and the Physical Environment
l Levels of Biological Organization l Biosphere l Ecosystems l Communities l Populations l Organisms
l Organs and Organ Systems l Tissues l Cells l Organelles l Molecules
Biological Themes l Life Requires Energy Transfer and
Transformation l Metabolism- the sum of all the chemical
processes in the body. l Anabolism- reactions that require energy. l Catabolism- reactions that release energy.
l Producers (autotrophs)- make their own energy.
l Consumers (heterotrophs)- feed on producers (and other consumers) to obtain energy.
Biological Themes l Structure and Function are Correlated at
All Levels of Biological Organization. l Example: ?
Biological Themes l The Cell is an Organism’s Basic Unit of
Structure and Function. l A cell is the lowest level of organization that
can perform all activities required for life. l Eukaryote- contains nucleus (that houses DNA) and
membrane-bound organelles; includes many forms of life (plants, animals, fungi).
l Prokaryote- does not have a nucleus (still has DNA- free floating in the cytoplasm); does not have organelles; smaller and less complex; includes bacteria and archea.
Biological Themes l The Continuity of
Life is Based on Heritable Information in DNA l Chromosomes
contain genes (which are passed from parent to offspring) that are made up of DNA.
Biological Themes l DNA provides instructions for making proteins,
which provide structure for cells/organisms, and help carry out cellular activities.
l Gene Expression- the process where info coded in DNA is used to make proteins.
l Genome- the entire library of genetic instructions in an organism.
l Genomics- studying sets of genes of an organism and comparing genomes between species.
Biological Themes l Feedback Mechanisms Regulate Biological
Systems l Negative Feedback- reduces the stimulus.
l Brings the body back to normal and helps restore homeostasis.
l Positive Feedback- amplifies the stimulus. l Not typically involved in homeostasis.
Warm Up- 2 tasks l On your warm up sheet, explain the
difference between positive and negative feedback.
l Please complete the “bug” worksheet that you picked up as you came in.
Evolution: Unity and Diversity of Life l Evolution- change over time
l Supports the idea that organisms living on Earth today are modified descendants of common ancestors.
l Taxonomy- the branch of biology that names and classifies species.
l FIGURE 1.14
Domains/Kingdoms l Archaea- prokaryotes l Bacteria- prokaryotes l Eukarya- multicellular eukaryotes
l Kingdom Plantae- autotroph (photosynthesis) l Kingdom Fungi- absorb nutrients from
surroundings l Kingdom Animalia- heterotrophs
*Protists- single and multi-celled eukaryotes
l FIGURE 1.15
Charles Darwin l On The Origin of Species (1859)
l Descent With Modification- contemporary species arose from a succession of ancestors.
l Natural Selection- a mechanism where the environment selects certain traits among natural variant traits in the population.
Charles Darwin l Darwin’s Observations
l Individuals vary in their traits, many are inherited.
l A population can produce far more offspring than can survive
l Species are generally adapted to fit their environments.
l Conclusion: individuals with traits best suited to the environment are more likely to survive and reproduce- creating more individuals with the advantageous traits.
Adaptive Radiation
Exit Slip l How is a mailing address analogous to
biology’s hierarchical taxonomic system? l Name the three domains of life, and the four
kingdoms discussed today.
Warm Up Exercise l Briefly describe Darwin’s general
conclusions in his theory of evolution. (2-3 sentences)
Science As a Process l Data- recorded observations
l Quantitative Data- recorded measurements. (contains numbers- frequently organized in tables and graphs)
l Qualitative Data- recorded descriptions. (no numbers)
Quantitative or Qualitative l The following data were collected by scientists
studying the feeding habits of the purple-throated hummingbird, Eulampis jugularis.
Quantitative or Qualitative l The males of the species are larger than the females. l The males’ bills are shorter and less curved than those of the
female. l The hummingbirds in the landscaped garden spent 21% of the
time feeding. Of that time, 20% was spent feeding on insects and 80% was spent feeding on nectar.
l The males get nectar from a species of Heliconia in which the flowers have shorter and less curved petals..
l The females get nectar from a species of Heliconia in which the flowers have longer and more petals.
l The hummingbirds in the forested area spent 23% of the time feeding. Of that time, 92% was spent feeding on insects and 8% was spent feeding on nectar.
Science As A Process l Hypothesis- a proposed answer to a
question. l Typically written in an “If...then” format.
l If… independent variable, then….dependent variable l Must be testable. l Must be falsifiable.
Experimental Design l Controlled Experiment- an experiment that
is designed to compare and experimental group to a control group. l Independent Variable- what is changed.
l When graphing, the independent variable is placed on the x axis.
l Dependent Variable- what is measured. l When graphing, the independent variable is placed
on the y axis.
*Observations and experimental results must be repeatable in order for an experiment to be considered valid.
Theory or Hypothesis? l Scientific theories are much broader in
scope than a hypothesis. l Theories can be used to derive new
hypotheses. l Theories are supported by substantially
more evidence than a hypothesis.
Facts About Science l Scientists work together.
l Peer Review- one scientist reading another’s work- checking it for validity.
l Science and technology are interdependent.
Exit Slip l Explain the difference between an
independent and dependent variable.