L2: Understanding Diversity

What are Systematics?

Systematics is the science of naming and classifying groups of organisms and determining relationships.

Name clues for evolutionary relationships (3)

Groups of organisms that are closely related tend to resemble one another due to genetic (DNA) similarity.

Features may be shared because of a common ancestor (evolutionary tree).

Systematists use key shared features-number of legs, flower structure, presence of a backbone to compare species.

What are convergent features? (2)

• Shared features: Evolved independently

• Shared traits

What are the domain system? (3)

Bacteria, Archaea, and Eucarya

What are the 6 kingdoms?

What was the first modern lineage to diverge from the universal ancestor?

Bacteria

After Bacteria, which organisms diverged next from the universal ancestor?

Archaea

What classification level do both Bacteria and Archaea belong to?

Each is both a kingdom and a domain

What kind of lifestyles are Archaea known for?

Extreme lifestyles

What is one characteristic of some Bacteria?

Some are disease-causing

What do Bacteria and Archaea have in common?

They are single-celled organisms that lack compartments or organelles (e.g., a nucleus).

What are organisms without compartments called?

Prokaryotes

What kind of structural plan do prokaryotic cells have?

A basic, common structural plan

What are the most abundant organisms on Earth?

Prokaryotes

Approximately how many individual bacteria are estimated to live on Earth?

About 5 × 10³⁰

In what extreme environments can prokaryotes live?

Harsh environments such as boiling hot geysers

What are prokaryotes called if they live with oxygen? Without oxygen?

With oxygen = aerobe; without oxygen = anaerobe

What is one key to the success of prokaryotes?

Their diverse ways of obtaining and using nutrients

What reproductive trait contributes to the success of prokaryotes?

High rate of reproduction

What two things does every organism need to sustain life?

A source of energy and a source of carbon

How do prokaryotes collect energy and carbon? (4 ways)

1) Obtain energy by consuming other organisms.

2) They can survive by consuming carbon-containing compounds that are not part of other organisms.

3) Use photosynthesis to produce sugars.

4) Some prokaryotes can get energy from iron or ammonia.

Do prokaryotic cells have internal compartments?

No, they do not contain internal compartments.

What do eukaryotic cells contain that prokaryotic cells lack?

Internal compartments called organelles.

What do organelles do?

Perform specialized functions (e.g., the nucleus contains DNA).

How may eukaryotic cells have originated?

Ancient prokaryotic cells may have engulfed other prokaryotic cells.

What is an example of an organelle thought to have originated from engulfed prokaryotes?

Mitochondria