Evolution; Chapter 5 A.Pre-Darwin Aristotle, E. Darwin, Lamarck, Paley B.Charles Darwin (1809-1882) Journey on H.M.S Beagle Origin of Species (1859) Branching

Evolution; Chapter 5

A. Pre-Darwin

Aristotle, E. Darwin, Lamarck, Paley

B. Charles Darwin (1809-1882)

Journey on H.M.S Beagle

Origin of Species (1859)

Branching Descent (with modification)

Natural Selection

C. More Evidence

D. Creationism controversy

Go to class web page

Textbook link

Download:deductionsanimal phylaanimal kingdom


What is evolution?

“process of lasting change among biological populations”


A. Pre-Darwin

Aristotle (d. 322 BC) ladder of nature

“chain of being”

Larmark (1809) parade of nature

adaptations (environment)

use/disuse

inheritance of acquired characteristics

Inanimate matter

Lower plants

Higher plants

Jellyfish, sponges, etc.

Humans

Whales and dolphins

Fish

Viviparous quadripeds

Snails, clams, etc.

Insects, spiders, etc.

Lobsters and crabs

Oviparous quadripeds

Squid and octopi

Birds

OBSERVATIONS:

There are lots of different organisms.

Many have remarkable adaptations.

Many have similarities

There are many differences

WHY?

A. Pre-Darwin


Darwin, E (d. 1802) change

Believed that individuals could change.

We are each slightly different than our parents.Thought individuals could pass traits to children.

A. Pre-Darwin



Believed that individuals could change.

We are each slightly different than our parents.Thought individuals could pass traits to children.

A. Pre-Darwin



Larmarck (1809) parade of nature

adaptations (to environment)

use/disuse


A. Pre-Darwin





e.g., domesticated animals

(environmental determinist)

A. Pre-Darwin





use/disuse


A. Pre-Darwin





use/disuse


A. Pre-Darwin




“Larmarck made the chain of being into a moving escalator which he called Nature’s Parade. The lowest forms of life, such as bacteria, formed by spontaneous generation from lifeless matter, and each species would slowly change (i.e., evolve) into the next higher species on the scale, without ever leaving any gaps”

Chapter 5 supplement: Scala Natura

There are lots of different organisms.

Many have remarkable adaptations.

Many have similarities

There are many differences

WHY?


A. Pre-Darwin

Larmark acquired characteristics

Paley Natural Theology (1802)

Sought to prove the existence of God by examining nature

Organisms have remarkable adaptations because they were “designed” (created) that way


A. Pre-Darwin

Larmarck acquired characteristics

Paley Natural Theology





Natural Selection

C. Evidence



On the Origin of Species by Means of Natural Selection (1859)

branching descent and natural selection

(with modification)




(with modification)

Species alive today came

from different species that

lived in earlier times

fig. 5-1




(with modification)

parents with genotypes that favor survival and reproduction leave more offspring than parents with less

favorable genotypes




M&M’s





Natural Selection

How did Darwin get to this point?


Journey on H.M.S Beagle (1831 to 1836)



Natural Selection

How did Darwin get to this point?



5 year voyage around the world as naturalist

Collected specimens and made observations





Different animals lived in different places

fig 5-2





Different animals lived in different places

(even when in the similar environments)





Galapagos Islands different Cape Verde Islands

(South America) from (Africa)

Each Island group was colonized from nearby mainland

Descent with modification led to differences




Descent with modification

Natural Selection

C. More Evidence


Return to England (1836)

British farmers artificial selection

Breeding the individuals with the most desired traits in each generation with each other, “improves” the species.

more milk, more wool,

different varieties of dogs, pigeons …

(positive eugenics)

pigeons

Thomas Malthus (1798)

•In nature, populations stay constant.

•Each species produces more offspring than necessary to maintain its numbers (so some die prematurely)

•Food supply is constant

Therefore, there must be competition.

“Can we doubt…that individuals having any advantage, however slight, over others would have the best chance of surviving and procreating their kind? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favorable conditions I call Natural Selection.” (Darwin)

A. Pre-Darwin







Natural Selection

C. Evidence


C. EvidenceMimicry

fig 5-4

C. EvidenceIndustrial Melanism

Moths (light and dark varieties) live on treesLichens (light color) also grew on tree trunks

Easy to see dark moths but not light ones.









Factories (industrial revolution) polluted areas downwind



Factories (industrial revolution) polluted areas downwind

Pollution killed lichens and soot darkened the trees

fig 5-5

C. Evidence

Homology

limb skeletonembryos

fig 5-6

C. Evidence

Homology

embryologyembryos

C. Evidence

Vestigial structures

coccygeal vertebraon skeleton

C. EvidenceFossils

fig 5-9

C. EvidenceFossils

fig 5-10

C. EvidencePost-Darwin

Modern synthesis:

` More complex than just “who survives to reproduce”

Genetic driftPunctuated

equilibrium

A. Pre-Darwin







Natural Selection

C. Evidence


Charles Darwin (1809-1882)

“Can we doubt…that individuals having any advantage, however slight, over others would have the best chance of surviving and procreating their kind? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favorable conditions I call Natural Selection.”


Natural Selection

natural events “select” organisms in such a way that the better adapted individuals tend to survive and reproduce.


Hypothesis:

All living things have developed from a common ancestor through the process of natural selection.

descent with modificationnatural selection

fig 5-1


Hypothesis:


descent with modificationnatural selection

1. If the hypothesis of evolution is true,

then there must be variation among

individuals within a species.

Deductions:

labybug variation


then there must be variation among

individuals within a species.

Deductions:

artificial selection - animal breedingplant breeding

e.g., pigeons

2. If the hypothesis is true,

then more offspring have to be born than survive.

Deductions:

2. If the hypothesis is true,

then more offspring have to be born than survive.

Deductions:

Elephants live for 90 years

have 6 offspring

after 500 years…….

15,000,000 elephants


then there must be a difference between the offspring that survive and reproduce and those that don’t.

Deductions:

Industrial melanism


then there must be a difference between the offspring that survive and reproduce and those that don’t.

Deductions:

Industrial melanismpesticide resistancesuper-bacteria


then species alive today should be different from species of the past.

Deductions:


then it must be possible to demonstrate the slow change of one species to another.

Deductions:

salamanders in California mountains


then there should be connecting forms between major groups.

Deductions:

birds

reptiles

mammals

amphibians

birds

reptiles

mammals

amphibians

Hypothesis:


We have examined 6 deductions made from our original hypothesis

The theory depends on:•individual variation •natural selection

Science is:

• a ongoing process• a way of knowing and investigating

the physical world• based on observation and

experimentation and reproducibility

• hypothesis testing• involves inductive and deductive

reasoning

Documents

Evolution; Chapter 5 A.Pre-Darwin Aristotle, E. Darwin, Lamarck, Paley B.Charles Darwin (1809-1882) Journey on H.M.S Beagle Origin of Species (1859) Branching