Biology 1107 - NIXON

A View of Life

1Chapter 01

Chapter 1

-A View of Life

-Process of Science

Diversity of Life

• Gastric-

brooding frog

Defining Life

Biology 1107 - NIXON

A View of Life

2Chapter 01

Defining Life (1)

• Living things vs. nonliving objects:

– Comprised of the same chemical elements

– Obey the same physical and chemical laws

• So, how do we define life?

– Several basic characteristics shared by all

What makes you different than a rock?

Characteristics of Life

• Organization (Cells)

• Acquire Materials & Energy (metabolism)

• Responses to Stimuli (Info)

• Reproduction

• Adaptations & Evolution

Levels of

Biological

Organization

Uni/Multicellular

Biology 1107 - NIXON

A View of Life

3Chapter 01

• Emergent Properties – Biological Organization

Emergent Properties: properties that are unique to

a level of organization and are due to interactions from previous levels.

– The whole is more than the sum of its parts!

Living Things:

Acquire Materials & Energy• Energy - the capacity to do work

– What’s the ultimate source of energy????

– Metabolism - all the chemical reactions in a cell

Homeostasis = the ability to maintain a

relatively stable internal environment (regulation)

consciousunconscious

Biology 1107 - NIXON

A View of Life

4Chapter 01

Respond to Stimuli (Info)

• Living things detect changes in environment

• Response often involves movement

– Vulture can detect and find carrion a mile away

– Tropisms in plants

• Behavior = how an organism responds to a

stimulus

Reproduce and DevelopMulticellular Organisms:

-union of sperm and egg

-developmental instructions encoded in genes

Evolution: Unifying Concept of Biology

Biology 1107 - NIXON

A View of Life

5Chapter 01

Evolution•Evolution:the change over time of the genetic

composition of populations

•Natural selection:

populations of organisms can change

over the generations if individuals having certain heritable traits leave more

offspring than others (differential reproductive success)

•Darwin found evidence for NS in ArtificialSelection…man selectively breeding

plants/animals

– If we can produce such drastic

changes in short time by AS, than NS over millions of years….

Evolution evidence: The Fossil Record

•Succession of forms over time

•Strata of Rock (sedimentary rock)

•Transitional links

Evolution evidence: Biogeography

•Geographical distribution of

species

•Darwin noticed species on Galapagos

resembled species on South American Immigrants more than similar islands

Biology 1107 - NIXON

A View of Life

6Chapter 01

Evolution evidence: Comparative Anatomy

•Homologous structures (homology)

– Similarities in characteristics that results from common ancestry (different functions)

– Genetic, Developmental, and Structural homology

•Vestigial structures

– Fully developed in one group but are reduced in another group.

Ex: whale/snake hindlimbs; wings on flightless birds, ??humans

Evolution evidence: Comparative

Embryology

•Pharyngeal pouches, ‘tails’ as embryos

•Postanal Tails

Evolution evidence: Biochemical Evidence

Darwin???

•Similarities in DNA, proteins, genes, and gene products

•Common genetic code

Biology 1107 - NIXON

A View of Life

7Chapter 01

Overview of Evolution

• Evolution is not a directed force!

• Organisms have differences – caused by????

• Different traits – higher fitness levels

• Not Progessive

• Natural Selection doesn’t create new traits, just selects those most favorable traits to THAT

PARTICULAR ENVIRONMENT.

• No such thing as higher or lower organism (move away from Aristotle’s Scale of Nature)

Organize Diversity using Taxonomy:

– Name and classify living organisms

Least inclusive to most inclusive

Taxon

Categorized by:-morphology-behavior-ecosystem

Now: compare genomes

Levels of Classification

• Z. mays• H. sapiens• Species

• Zea• Homo• Genus

• Poacae• Hominidae• Family

• Commelinales• Primates• Order

• Liliopsida• Mammalia• Class

• Anthophyta• Chordata• Phylum

• Plantae• Animalia• Kingdom

• Eukarya• Eukarya• Domain

• Corn• Human• Taxon

Biology 1107 - NIXON

A View of Life

8Chapter 01

The Eukaryotic Kingdoms

Scientific Names

• Binomial nomenclature (two-word names)

• Universal (avoid common names)

• Latin-based

– Genus name is capitalized

– Species name is lower case

– Underline if handwritten or italicized if typed

– Common to abbreviate the genus name

Biodiversity:

-Abundance of species

-Variability of their genes

-Different ecosystems in

which they live

Estimated as high as 15 million (2 million id/named)

Extinction is:

-death of a species

Biology 1107 - NIXON

A View of Life

9Chapter 01

Organized process for seeking answers to a problem (question)!

7 Major Steps:

1) Make an observation

2) Identify a problem/question

3) Gather Information/Research

4) Form a hypothesis – trial solution/explanation

-Reasoning: Inductive (combine isolated facts into larger statement)

-Ex. The sun always rises in the east or All organisms are made of cells

5) Experiment – to test your hypothesisReasoning: Deductive

-Ex. (premise 1) all organisms are made of cells

(premise 2) humans are organismsthen humans are composed of cells

Set up a controlled experiment that has:1) Control Group

2) Experimental Group

These two groups are identical except for 1 factor!

Parts:Independent (experimental) variable –

Dependent variable (responding)-

Constants (controlled variables)– parts that are the same within your experimental and control groups

Procedure – one or more paragraphs

6) ResultsAll data will be here (graphs, charts, etc.)

Is the data reliable?

Don’t analyze data here

2 Types of Data:

7) Draw Conclusions

Does it support the hypothesis? Support vs does not support!

After collecting data, a scientist may make an inference.

• Inference=a logical interpretation based on prior knowledge or experience.

• (Example – researcher tests certain parts of a reservoir and infers that all the water is safe to drink).

Hypothesis vs. Theory?