Life Science I83.101.102

Dr. Ekaterina (Kate) VorotnikovaOffice: 413b

E-mail: Ekaterina_Vorotnikova@uml.edu

Lecture 2Evolution, biosphere, and science

(pages 9-16)

Essentials of Biology Second EditionSylvia S. Mader with McGraw-Hill Connect Biology

 Mader, Essentials of Biology 2E with CONNECT Plus Access Card

Course: Life Science 83.101.102 

Student registration info

Instructor: Ekaterina Vorotnikova  

Section: Spring 2010 mwf 9 am 

online registration instructionsGo to the following Web addressand click the "register now" button:

http://connect.mcgraw-hill.com/class/e_vorotnikova_spring_2010_mwf_9_am

This is a unique address for Spring 2010 mwf 9 am

(http://connect.mcgraw-hill.com/class/e_vorotnikova_spring_2010_mwf_9_am)

Web addresses cannot contain spaces. Use lowercase letters or numbers or special characters ( '-' and '_' ) only.

Assignments for a 1/25 week:

1. Lec 1 Assignment

2. Quiz 1

3. Work on LearnSmart study modulus to study chapter 1 until Feb.2

Due on Monday Feb. 1 at 11:00 p.m.

Final grade

Grade for exams – 50%;

Grade for assignments – 30% (20% for assignments + 10% LearnSmart activity);

Grade for quizzes – 20%

(100 points max + 5 points for attendance.)

Total number of points -105.

 

Evolution, the Unifying Concept of Biology

• Despite diversity, organisms share the same basic characteristics

– Composed of cells organized in a similar manner

– Their genes are composed of DNA

– Carry out the same metabolic reactions to acquire energy

• This suggests that they are descended from a common ancestor

ClassificationTaxonomy:

Discipline of identifying and classifying organisms according to certain rules

Hierarchical levels (taxa) based on hypothesized evolutionary relationships

Levels are, from least inclusive to most inclusive:

Species, genus, family, order, class, phylum, kingdom, and domain

A level (e.g. phylum) includes more species than the level below it (e.g. class), and fewer species than the one above it (e.g. kingdom)

Scientific Names• Binomial nomenclature (two-word names)-

used to assign each organism with two part name e.g. Homo Sapience

• Universal

• Latin-based– First word represents genus of organism e.g. Homo

– Second word is specific epithet of a species within the genus e.g. Sapience

– Always italicized as a Genus species (Homo sapiens)

– Genus may be abbreviated e.g. Escherichia coli as

E. coli

TaxonomyLeopard: Panthera pardus

Jaguar: Panthera onca

Tiger: Panthera tigris

Lion: Panthera leo

Domain: Eukarya

Kingdom: Animalia 

 Phylum: Chordata 

 Class: Mammalia 

 Order: Carnivora 

 Family: Felidae 

 Genus: Panthera 

 Species: P. pardus; P. onca; P. tigris; P. leo

Miniature Muntjac, Muntiacus putaoensis Rhacophorus suffry

Crossota millsae, a brilliant red and purple jellyfish found at a depth of 2000m in the Arctic Ocean

The small blue jelly, a type of Narcomedusae, is new to science.

Domains

Common ancestor

• Bacteria : Microscopic unicellular prokaryotes

• Archaea: Bacteria-like unicellular prokaryotes;

Extreme aquatic environments

• Eukarya: Eukaryotes – Familiar organisms

PR

OK

AR

YO

TE

S

EU

KA

RY

OT

ES

DNA(no nucleus)

Prokaryotic cell

Membrane

Eukaryotic cell

Nucleus(contains DNA)

Organelles

1-10 µm

10-100 µm

Evolution, the Unifying Concept

of Biology

In 1859, Charles Darwin (12 February 1809 – 19 April 1882) published On the Origin of Species by Means of Natural Selection, presenting a strong, logical explanation of descent with modification, evolution by the mechanism of natural selection.

Evolution is descent of species from common ancestors, with genetic modifications that make each species more suited to its environment.

Randal Keynes, 62, is the great-great-grandson of Charles Darwin. He is also the author of the book Darwin, His Daughter, and Human Evolution, inspiration for the new film Creation, starring Paul Bettany and Jennifer Connelly. The film opened last Friday and gets a wider release Jan. 29.

Natural Selection

A process in which steps 1-3 result in population adapted to the environment (4)

1.The members of a population have heritable variations: differences in their DNA that can be passed from one generation to the next.2.The population produces more offspring than the resources of an environment can support.3.The more adapted individuals survive and reproduce to a greater extent than those that lack the adaptations.4.Across generations, a larger proportion of the population becomes adapted to the environment.

Descent with Modification.

The various species of Hawaiian honeycreepers all evolved from one species of finch which originated in North America and arrived in the Hawaiian Islands millions of years ago. They have different bill shapes adapted to different kinds of food: flower nectar, seeds, fruits, insects..

All honeycreepers still share certain characteristics from common finch ancestor – body shape, nesting behavior, etc.

23

Organization of the Biosphere• Population - Members of a species within

an area

• Community - A local collection of interacting populations

• Ecosystem – A community plus its physical environment

• How chemicals are cycled and re-used by organisms

• How energy flows, from photosynthetic plants to top predators

A grassland, terrestrial ecosystem

1. Chemicals cycle through an ecosystem.

2. Energy flows through ecosystem and dissipates as heat.

What are two most biologically diverse ecosystems?

Science: A Way of Knowing• Biology is the

scientific study of life.

Biologists

• Scientific method begins with observations.– May take advantage of

knowledge and experiences of other scientists

• Scientist uses inductive reasoning – uses creative thinking to combine isolated facts into a cohesive whole.– Hypothesis – possible

explanation for an event• Consider only those that

can be tested.

Flow diagram for the scientific method

• Experiments further observations and test hypothesis.– Good experimental design,

all conditions constant except experimental variable

• Test group versus control group

– Data may suggest correlation.

• Does not necessarily mean causation

• Scientists are skeptics

• Conclusion – is the hypothesis supported or not?– Experiments and

observations must be repeatable.

• Scientific theory– Ultimate goal of

science is to understand the natural world in accepted explanations for how the world works.

– Cell theory, gene theory

– Theory of evolution is considered a unifying concept in biology.

– Some biologists refer to the principle or law of evolution due to over 100 years of support by so many observations and experiments.

Controlled study

• Hypothesis :

Antibiotic B is better than Antibiotic A in current use for the treatment of ulcers.

Controlled laboratory experiment to test the

effectiveness of a medication in humans

3 experimental groups

Reduce possible variances by randomly dividing large group.Control group receives placebo.

The Scientific Method– Begins with observation

– Hypothesis

– Experimentation (Purpose is to challenge the hypothesis)

– Often divides subjects into a control group and an experimental group

– Predicts how groups should differ if hypothesis is valid

– Results or Data (Observable, objective results from an experiment)

– The results are analyzed and interpreted

– Conclusions are what the scientist thinks caused the results

Scientific Theory• Scientific Theory:

– Joins together two or more related hypotheses

– Supported by broad range of observations, experiments, and data

• Scientific Principle / Law:

– Widely accepted set of theories

– No serious challenges to validity

Biodiversity• Biodiversity is variation in life on Earth, in a zone of

air, land, and water where organisms exist (the number of different species)

– Abundance of species estimated about 15 million.

– Fewer than 2 mln. have been identified, named and classified

– The variability of their genes, and

– The ecosystems in which they live

• Extinction is:

– The death of the last member of a species

– Estimates of 400 species/day lost worldwide