Week 1 Bio PPT Notes

Populations and species evolve,

meaning that their heritable

characteristics ____ through

time

change

Evolution definition:

Change in allele frequencies over time

-Works at population & species level

Mechanism →

natural selection

How did life begin

Science → facts

Why did life begin

Religion → faith

What is typological thinking?

Species remain unchanged, fixed, & static

Who was a famous example that supported that

style of thought?

Charles Darwin & Alfred Wallace

How was diversity organized?

Natural Selection- survival of the fittest

How did Lamarck think change happened?

Inheritance of acquired characteristics;

-environment causes modifications in individual

-offspring use/disuse structure & bring back change in species

Why was Lamarck’s idea of change discredited?

The mechanism of how they changed and passed those changes on

(through genes not traits itself)

Charles Darwin & Thomas Alfred Wallace Evolutionary Theory:

Evolution is descent with modification

-offspring with inherited characteristics able to compete for resources & reproduce (than those unable to compete)

Darwins proposed mechanism:

Natural Selection

Evolution changes:

1. Species accumulate differences

2. Descendants differ from ancestors

3. New species arise from existing ones

If frequencies of alleles change?

Population is undergoing evolution

Survival of the fittest

(Natural selection) reproductive success with those with favorable traits

People make the choice

(Artificial selection) human influence. ex: crops, domesticated animals

Theory of Evolution Claims:

1. Species change through time

2. Species are related by common

   ancestry.

Support for claims:

1. Vast Geologic Record and Fossils

2. Extinct species

3. Transitional features

4. Vestigial structures

5. Species changing today

6. Geographic Relationships

7. Related Species Share Homologies

How are fossils formed?

-Show gradual evolutionary changes over time (millions of years)

-Used to determine when organisms lived relative to each other

Geologic dating:

-The overall science (geochronology) of determining the chronology of Earth's history.

-Assigns actual years before present (e.g., 200 million years ago).

Radiometric dating:

- A key absolute dating technique using constant decay rate of radioactive isotopes (parent/daughter elements) within minerals.

-cCalculates when minerals crystallized or when organic material formed.

(ex: U-PB (uranium lead))

How old do we think the earth is?

4.54 billion years old

When did the first fossils form?

3.5-3.7 billion years ago

Transitional features

-aka homologous structures

-presence of structures in organisms that share the same basic form

What is a vestigial trait or structure?

-unused structures without function

Why do vestigial structures support change in species over time?

-appear to be residual parts from a past common ancestor

Species changing today:

-Antibiotic resistance

-Pesticide resistance

-Herbicide resistance

-Documented changes in populating counting days, months (TB, Galapagos finches, lizard survival during hurricanes)

Geographic relationships:

distribution of organisms on the planet follows patterns explained best by evolution in conjunction with tectonic plate movement over geological time

Biogeography:

Development and presence of species based on location

-groups that evolved before Pangea broke up are distributed worldwide

-groups that developed after the breakup appear only in certain regions/continents (e.g. Australian marsupials)

Homology definition:

Similarity in characteristics resulting from a shared ancestry

Structural homology:

-type of homology

-similarity in adult morphology.

Genetic homology;

-a similarity in the DNA sequences

of different species.

Developmental homology;

-structures appearing early in development are similar.

Phenotypic plasticity:

the ability of a single genotype to produce multiple phenotypes in response to variation in environment

Epistasis:

environment/possible changes