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.