Exam 1: Unity, Diversity, and Evolution

Why is the theory of evolution important to all biologists?

It unifies all of biology. It accounts for the unity and diversity of life. It provides a guide to help us better understand organismal form and function.

What is speciation?

When one ancestor diverges into two new species. When two species emerge from a single common ancestor.

What were Darwin's three main observations?

1. Individuals in a population have traits that vary and many of these traits are heritable (pass from parent to offspring) 2. More offspring are produced than survive so competition is inevitable 3. Species generally suit their environment

What two inferences did he make from these observations?

1. Individuals that are best suited to their environment are more likely to survive and reproduce 2. Over time, more individuals in a population will have those advantageous traits

When did Darwin publish, "On the origin of species by means of natural selection"?

1859

What is a population?

A group of individuals of the same species, at the same place at the same time.

Why are there so many different finch species on the Galapagos Islands?

Adaptive radiation Exploitation of a new resource to alleviate competition.

What are the two main types of speciation, and which one is more common?

Allopatric, sympatric - allopatric

List the 3 domains.

Archaea, Bacteria, Eukarya

Why do all mammals have fur at some point in their lives?

Because fur was a derived character on the mammal phylogeny. In other words, the common ancestor of all mammals probably had hair as well.

Why are the bones in our arm the same bones as those in a chicken's or a whale's flipper?

Because they are homologous structures - structures that are similar because they are derived traits from a common ancestor.

According to taxonomic rules, what is the proper way to write a scientific name (genus and species name) in scientific literature?

Genus name capitalized , species name lowercase, both italicized or underlined

Describe how natural selection can cause a population to change.

If there is differential survival of individuals with a particular trait that varies along a continuous gradient (like color in the insect example) and this trait is heritable (Variation is driven by genetic differences), then selection would lead to some genes becoming less common and other genes becoming more common in the population over time.

Why is reproductive isolation important during speciation?

If they were still reproducing, if there was no isolating barrier, gene flow would continue between the 2 populations and it would be difficult for these two populations to diverge. ( To evolve independently of one another.) If there was continuous mating any novel mutation in one population would be shared with the other.

Do individuals evolve?

No

What are the 7 properties of life?

Order, evolutionary adaptation, reproduction, response to the environment, growth and development, energy processing, regulation.

How does the theory of evolution account for the unity of life (shared characteristics)?

Organisms with a recent common ancestor will possess many of the same structures as one another because the common ancestor of both species also possessed those features.

List the 3 multicellular kingdoms in domain Eukarya.

Plantae, Animalia, Fungi

How does sympatric speciation work? Describe a hypothetical example that illustrates sympatric speciation.

Speciation occurs between two population that share the same range. Polyploidy could cause this. Competition - as in the case of the cichlids or finches, drives individuals from the population to use different resources in different areas.

What is meant by "unity within the diversity of life"?

That organisms share features because they arose through descent (with modification) from common ancestry.

In one sentence define evolution.

The change in genetic composition of a population over successive generations. Evolution is the process by which different kinds of living organisms have developed and diversified from earlier forms during the history of the earth.

How does allopatric speciation work? Does it require natural selection?

There is a separation between 2 populations which were once one continuous population. Yes - It could be a founder effect that began the process (a small group of individuals becomes separated from the rest of the population). However in the time it would take to get divergence selection would have to be operating on these traits.

What would happen if two isolated populations come back together and have NOT evolved reproductive isolation?

They would be able to mate. They would share genes and expand their gene pool for that species. There would not be a speciation event.

List the 8 major taxonomic categories from biggest (most inclusive) to smallest (least inclusive)?

domain, kingdom, phylum, class, order, family, genus, species