Chapter 5 Biology

What is taxonomy?

The science of naming and classifying organisms

What is binomial nomenclature?

Two word naming system

How did Linnaeus group species?

He grouped them according to their major physical characteristics (ex. number of legs or leaf shape).

Today we group organisms based on _______ __________

evolutionary relationships

3 Domains

Bacteria - common bacteria, Archaea - bacteria that live in extreme environments, Eukarya - all eukaryotic organisms

4 Kingdoms of Classification

Plant, Animal, Protist, Fungi

What was Charles Darwin’s contribution to science

An English naturalist. He traveled the world for years studying and collecting specimens.

2 important ideas darwin proposed

1. Evolution occurs - he proposed that species change over time instead of being created, and then remaining unchanging

2. Evolution occurs because of Natural selection - individuals with beneficial traits produce more offspring.  Over time this changes the traits in the population.

Did Charles Darwin discover evolution?

HOW it happened

Where did Darwin travel?

Galapagos Islands and South America

Darwin’s observations on his voyage

1.He found fossil seashells on the top of mountains.
2. Found fossils that should be a low elevations
3.. Experienced an earthquake and saw a sea floor rise up
4.. He found fossils of extinct animals that were both similar and different from modern day animals. He wondered if they could be related.

What organisms Darwin study on the Galapagos Islands

Finches and Tortoises

4 conclusions, what are they of theory of Evolution

1. Variation exists in every population.

2. Populations produce more offspring than can survive.

3. Resources are always limited so some individuals will be more successful than others.

4. Individuals that are more “fit” will have more surviving offspring. Their traits will become more common in the population.

What are fossils?

the preserved remains or traces of organisms that lived in the past

What does extinction mean?

permanent loss of a species from the ecosystem

What are homologous structures

same structure, different function

What are analogous structures

• Body parts that share a common function, but not structure

What did Darwin conclude about comparing embryology

more similar developmental stages indicated more recent common ancestry.

What is a vestigial structure

•  is one that is reduced in size and function

Example of Vestigial structure

Hind legs on a whale, cave fish eyes

Example of homologous structure

The humerus bone in humans, cats, whales, and bats

Example of Analogous Structures

Wings or the ability to move through the air

What is a cladogram

Diagram that shows the evolutionary relationships among a group of organisms

Know that organisms with similar DNA/ amino acid sequences share a more ____________

recent common ancestor

What is biogeography

the study of the distribution of organisms around the world, and why organisms live where they do.

How does biogeography relate to adaptations in organisms

The environmental conditions in each country were different so different traits were more advantageous in each.

• Adaptations are traits that best suit a given environment.

_______ are organisms that can and do reproduce to make live, viable, and fertile offspring

Species

What is adaptive radiation

•  the process of a single species evolving into new species as they adapt to different environmental conditions.

• Ex. Galapagos finch 

What are the 5 causes of change in allele frequencies in a population? Know each one’s meaning

1. Mutation

2. Gene flow

3. Genetic drift

4. Natural selection

5. Sexual selection

Mutation

the random change in DNA of an individual

In order for speciation to occur, what needs to happen?

For speciation to occur, some members of the population must become ISOLATED from the rest.

Gene Flow

the movement of individuals into or out of a population

Genetic Drift

the random change in allele frequencies due to loss of population

Two types of genetic drift

bottleneck effect and founder effect

What is the bottleneck effect?

A change in allele frequency following a dramatic reduction in the size of a population that more than likely was from a natural disaster

What is the founder effect?

change in allele frequencies as a result of the migration of a small subgroup of a population

What is disruptive selection?

favors individuals at both extremes of the phenotypic range as a response to natural selection

What is stabilizing selection?

favors intermediate variants and acts against extreme phenotypes when in response to natural selection

What is directional selection?

favors individuals at one end of the phenotypic range when in response to natural selection

Natural Selection

the change in a population’s allele frequencies due to environmental pressures

Sexual Selection

the change in a population’s allele frequencies due to reproductive pressures

What does “fitness” mean in evolution

refers to how well suited an organism is for the current environmental conditions.

What are the 3 types of selections in natural selection based on environmental changing

Stabilising Selection

Directional selection

Disruptive selection

What do the 3 graphs represent and what's happening

The top image is of our initial population.  Most of the mice are medium brown.  A few are lighter and a few are darker.

The three images below show how the phenotype changes based on the selective pressure on the population.

The white arrow represents which color of mice are being selected against or are removed from the population.

The solid blue line is the final distribution of of mice after a few generations of that pressure.

What needs to happen in order for speciation to occur

some members of the population must become isolated from the rest.

What are the ways in which it can occur

Temporarily Isolated, Reproductive Isolation

What is temporal isolation?

A type of isolation that occurs when two or more species reproduce at different times

What is behavioral isolation?

A type of Isolation caused by differences in courtship or mating behaviors

What is geographic isolation?

A type of isolation in which populations are physically separated and therefore never mate

Isolation, how does isolation happen

Geographical isolation, Allopatric speciation, Sympatric speciation

What is coevolution

process by which two species evolve in response to changes in each other over time

Example of coevolution

Flowers and pollinators

What does punctuated equilibrium mean

Evolution occurs in rapid bursts of speciation, followed by long periods of no change.

What happens when the environment changes slowly instead of quickly

We see gradual speciation events. This is what Darwin predicted would be found in the fossil record.