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Biology - study of life

All living things:

1. sense and respond to environment

2. capture and use energy

Metabolism = all the chemical reactions in a cell

Homeostasis = maintain internal operating conditions

within a range

3. reproduce, develop, grow

New cells only arise from previous cells

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4. are composed of at least one cell Some unicellular

Some multicellular

5. contain DNA Genes provide the instructions for the cell

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Genus and species

Binomial nomenclature

every living organism has two names which represent the genus and species

Felis domesticus F. domesticus

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Life’s diversity

•2 million species have been described

•Half are…..

•could be over 15 million species

•Living things are classified = Taxonomy

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No nucleus in cell Presence of nucleus in cell

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Eukarya Kingdom Animalia motile, multicellular,

consumers

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Fig 19.6 Sponges are most primitive,

vertebrates are most advanced animals

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Example of an animal useful to humans

Diabetes drug from venom/saliva

Gila monster (lizard)

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Kingdom Plantae (400 million years)

370 feet

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Plants – characteristics?

Multicellular

Most are flowering

Photosynthesis

light

CO2 + H20 ------> O2 + starchSunlight is ultimate energy source for life – why?

Plants are producers

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Example of a plant useful to humans: Aloe

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Kingdom Fungi = molds, fungus, yeast

•Secrete chemicals to break down and

absorb food from dead or living matter

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2 important fungal medicines:

Cyclosporin (1971) Tolypocladium inflatum

Suppresses immune system… so…..

Used in organ transplants, psoriasis,

rheumatoid arthritis

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Penicillin antibiotic

From bread mold

Revolutionized medicine

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PRODUCERS

CONSUMERS

DECOMPOSERS

Fig. 1.4

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Kingdom Protista also called protozoa

Includes algae and

seaweed!

And some unicellular

organisms

Algae, Paramecium, amoeba

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A useful protozoan

red algae (Chondrus crispus

Contains carageenen)

Thickener

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Domain Bacteria

3.5 billion years old

Prokaryotic cells

No nucleus

Single-celledintestine

plant

roots

On octopus mouth

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Domain Archaea

Methanosarcina mazei makes

methane from acetate

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Extremophiles

Have been found in thermal vents, salt crystals, ice,

acid environments

Extraterrestrial life?

I

MARSGeyser (hot!)

“Chance favors the prepared mind” Louis Pasteur

SCIENCE Science - a process of discovery

objective

explain world using natural

processes

fish dead

because there

was a curse on it

fish dead

because there’s

no food in its

tank

Why is the fish dead?

Scientific method

I. OBSERVATION

2. HYPOTHESIS

educated guess

comes before the experiment

must be testable and falsifiable

Hypothesis must be Testable

• Zinc lozenges ward off the common cold

• Colds are disturbances in psychic energy

• Meditation improves the immune system

– Hypothesis must be falsifiable

– Eggs lead to heart disease

– The earth is round

Hypothesis – educated guess

Theory – supported by all data, a unifying

concept

Theory of gravity

Round earth

Mars year = 687 earth days Mercury = 87.8 earth days

The Scientific Method1. Observation

2. Hypothesis

3. Experimental Design

1. Experimental (independent) variable

2. Controlled variables

3. Control group = often a “no treatment” group

4. Measurement (dependent variable)

Never ignore data and stay away from

preconceived ideas

minimize bias

1. Double blind studies

Randomized

Controlled

2. Placebo

Placebo effect

The placebo effect = observable or felt

improvement in health not attributable to

treatment.

In a double-blind, placebo-controlled study of 30 people

with carpal tunnel syndrome, use of a static magnet

produced dramatic and enduring benefits, but so did use

of fake magnetsCarter R,. J Fam Pract. 2002;51:38–40.

When participants in a trial of a new drug for reducing

cholesterol are given a placebo their cholesterol

levels are likely to fall significantly. Why?

A double blind randomized study prevents bias.

Reading graphs

A double blind, randomized

experiment was conducted.

100 people drank echinacea tea

every day for 4 months of winter.

100 people drank tea made with a

placebo. All subjects got colds.

The subjects were assessed for

severity of cold symptoms.

Evolution

Change through time

Change over time

“all organisms present of Earth today are

descendents of a single common ancestor

and all organisms represent the product of

millions of years of evolution”

Also known as common descent

Species

Group that can interbreed

Microevolution

Change within a species or population over

time

Speciation

New species arise from ancestral species

What is a Species?

One species is reproductively isolated from other

species.

Shares gene pool

HobbsMale lion female

tiger male ligers are

sterile, female ligers

are fertile

All humans share a common ancestor

Horses have undergone much speciation

Sharks have changed very little in 40

million years

Megalodon, a 50 ft shark that

lived ~20 million years ago

Natural Selection

How do we know what happened a long

time ago (geological time)?

250 mya Pangaea – continents came together

dramatic environmental change

mass extinction

Fig 16.13

Geological Time Scale

Age of Earth:

When living organisms first appeared:

Humans have been on Earth for 0.04% of the history of life

Natural selection

Natural Selection and common

descent (1859)

Charles Darwin T.H.

Huxley

HMS Beagle

Galapagos Islands

Volcanic islands off coast of Ecuador contain unique

species of plants and animals

Tortoise marine iguana

1836

Video

iguana

ala

Adaptive radiation

FINCHES HAVE ADAPTED TO ENVIRONMENTS

Fig. 14.6

Diet of seeds

Beak to catch insects

Probes cacti for nectar

All descended from a single ancestral species

Natural Selection – how does it

work?

1. Random variationA. All populations of organisms vary randomly

Variations are NOT imperfections but a normal aspect of

species

B. Variation occurs due to mutation and

sexual reproduction

mutation = heritable change in DNA

DNA also rearranges during formation of sperm

and egg

C. Variation inherited from parent to offspring

What is a mutation?

Most are neutral mutations : no effect on fitness

“Mutant” melanin gene normal melanin gene

Blond phenotype brown phenotype

A few are harmful mutations :

hemophilia

A few are positive mutations :

beneficial (longer neck in giraffe)

2. Not all offspring survive

Examples: 1 sea star has 4 million offspring – which survive?

3. “Survival of the fittest”=

The most “fit” organisms survive andpass their genes on

Fitness is determined by the environment

Fitness = reproductive success

THIS IS NATURAL

SELECTION

Another adaptation to

avoid predation

Fig 14.9

Brazilian alligator bug

The most fit organisms survive to reproduce

Traits that increase fitness are adaptations

Examples of adaptations (increase

fitness)

Offspring inherit traits of parents =

4. Descent with modification =

Evolution

Natural selection results in adaptive traits

increasingly represented in each

succeeding generation

May take a lot of time for change to be

obvious and/or lead to a new species

Speciation

Ancestral species give rise to new species

Artificial Selection – breeding of domesticated

animals and plants by humans, this is NOT natural

selection Cows, corn, dogs

Bulldog HHMI video

1. GeologyEarth does change

Not all due to catastrophy

Shaped by gradual, natural, slow processes

erosion, wind, rain

How old is the earth?

The Grand Canyon was not

produced by a catastrophe

Arizona

2. Fossils History of life recorded by remains of past

Buried in volcanic ash or sediments for >10,000 years

Types

Impression

Bones, teeth

Amber

Petrified wood

Mosasaurus

Tooth 50 ft. 70 mya

Why is the fossil record

incomplete?

75% of the earth is ocean

Many destroyed by weather

Fossils don’t always form A small number are buried in the right way (fast) to prevent decomposition

Cant dig up entire earth

No soft parts

Only the hard parts remain after fossilization process

99% of species once alive are extinct

Stratification: simple=oldest= deepest

Succession of life

forms

Hadrosaurus, Haddonfield, NJ 1858

The NJ State Dinosaur

Coelacanths!

1938, a Coelacanth was caught at the mouth of the Chalumna River on the east coast of South Africa.

70 million year old fossil

Fossils found a few years ago

A bison-size rodent, Phoberomys pattersoni, grazed

on aquatic grasses and roamed the riverbanks of ancient

Venezuela about 8 million years ago.

Glyptodon and modern

armadillo

Ancient whales

Kutchicetus 40 mya

A famous hominid fossil

1974, Hadar, Ethiopia.

Lucy – (Australopithecus afarensis)

East Africa ... 3.2 million years ago

300 individuals found 3 feet 8 inches tall More ape-like than human

1. Australopithecus

afarensis

2. Australopithecus

africanus

3. Homo habilis 4. Homo erectus

5. Neandertal

archaeopteryx- a

dinosaur/bird link

Late Jurassic period, and specimens have been found in limestone deposits in Bavaria, West Germany. The first specimen was discovered in 1861, and since then six skeletons have been found.

3. transitional forms

monitor lizard “Komodo dragon”

500 lbs 10 feet

Indonesia Varanus komodoensis

4. Biogeography

•Animals on each

continent related

•Islands species related

to species on mainland

5. Anatomy

Homologous

structures

Share a common

evolutionary history but

may be used for

different functions

Fig. 14.14

Analogous structures

similar function but no shared evolutionary

history

Vestigial structures

Function lost during

evolution, no longer

needed

human appendix, whale leg

bones, snake leg bones

http://images.google.com/imgres?imgurl=http://www.freedive.net/images/whlshrk.jpg&imgrefurl=http://www.freedive.net/wshark.html&h=335&w=466&sz=28&tbnid=S5sgbnfVSMoJ:&tbnh=89&tbnw=123&start=40&prev=/images%3Fq%3Dwhale%26start%3D20%26hl%3Den%26lr%3D%26ie%3DUTF-8%26sa%3DN

6. Embryology

vertebrate body

plan for

development

= shared descent

DNA evidence of relatedness of

species

Humans share 99.9% of DNA

Human DNA is 99.01 % similar to

chimp

90% with mice

Pre- and post-evolutionary theory,

page

Mammals- what makes a mammal a mammal?

Ex. Duckbilled platypus

Monotremes are the most

primitive mammals

Ornithorhynchus anatinus

Marsupials – development in

pouch

Placental mammals

Born more fully developed

Placenta in uterus

Ex. Bat, polar bear, human, whale, cow,

armadillo……..

Review

Your notes are important – rewrite them or

type, study them and refer to textbook

This review is not comprehensive

Good luck on exam 1.

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DOMAIN Archaea? Bacteria? Eukarya?

Prokaryotic

Protista

Live in extreme environments

Penicillin

Photosynthesize

Eukaryotic

Includes worms and beetles

Onion

E. coli

KINGDOM Animalia Plantae Fungi Protista

Cyclosporin

Producers

Aloe

Use sun as energy

Some are single celled

Poisonous dart frog

Consumers

Coelecanth

Mold

Producers

Yeast used to make bread and beer

Photosynthesis

Motile and multicellular

Absorb living or dead matter

Duckbilled platypus

Microscopic

Lucy

Homo sapiens

Animals

What are

Mammals Animals

Homo sapiens Plants

Genus Homo Sponge

Sharks Hybrid

Vertebrates Platypus

Kangaroo Fungi

Snakes Hadrosauras

Archeopteryx Lucy

Common descent (yes or no)?

All living things share a common ancestor

All life was created a few thousand years ago

All species that have ever lived were created at

the same time

Species have given rise to new species over time

All species of living things lived during the same

time period but some have died out

Life is about 3.6 billion years old

The first living things on earth were single-celled

bacteria

The Earth is about 4.7 billion years old

Homologous ?

Bird wing and bat wing

Dolphin flipper and bat wing

Snake tail and human coccyx

Appendix and coccyx

Penguin flipper and shark fin

Human arm and chimp armWhich are vestigial?

Fossil (extinct) or alive today? Dinosaur Hadrosauras

500 pound rodent Archaeopteryx

Eukaryotes Archaea

Coelacanths Whales with legs

Neanderthal man Descendants of dinosaurs?

Homo sapiens Archaea

Homo erectus Whales with internal leg bones

Mammals that lay eggs

Protists

Megalodon (giant shark)

Komodo dragon (monitor lizard)

Which is a transitional form?

How do these disciplines provide evidence

for species changing over geological time?

Anatomy – homologous and vestigial structures

Geology – catastrophies and slow changes

Embryology and a vertebrate body plan

Biogeography and relatedness of species

Paleontology and the discovery of fossils and

transitional fossils

DNA science and comparison of DNA of species

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concepts

Metabolism Hypothesis and theory

Homeostasis Double blind study

Life Biology

Photosynthesis Placebo

The scientific method

Erosion

Speciation

Evolution by natural selection

Common descent

Microevolution

Embryology

Species

The scientific method

Scientists studied 400 people who have psoriasis. All have suffered from this skin condition for at least 10 years. One group of people are given the immunosupressant, cyclosporin, every day for one month. The other group took a placebo. After one month, the effects of the drug on psoriasis was measured.

1. What is the hypothesis?

2. What is the experimental variable?

3. What is the control group?

4. How would you make this a double blind experiment?

5. What are 3 controlled variables?

6. What is measured?

Why does the control group take a pill at all?

When making the two groups, why not put all the severe sufferers in

the + drug group and the less severe ones in the control group?

Interpret the graph