Broad Patterns of Evolution

Question 1

Order of Geological Periods

Answer 1

1) Cambrian
2) Ordovician
3) Silurian
4) Devonian
5) Carboniferous
6) Permian

Question 2

Ancestors of Modern Mammals

Answer 2

• cynodonts
• synapsids
• therapsids

Question 3

At what time was most of the landmass of Earth consolidated into one supercontinent?

Answer 3

from 1 billion years ago to about 250 million year ago

Question 4

What is scenarios from which an adaptive radiation might directly arise?

Answer 4

• vacant ecological niches
• evolutionary innovation
• an adaptive radiation in a group of organisms (ex. plants) that another group uses as food
• colonization of an isolated region that contains suitable habitat and few competitor species

Question 5

Example of Adaptive Evolution

Answer 5

the more than 500 species of fruit fly on the various Hawaiian Islands (all descended from a single ancestral species)

Question 6

Striking Adaptive Radiations

Answer 6

• have occurred over limited geographic areas
• can be initiated when a few organisms make their way to a new (often distant location) in which they face relatively little competition from other organisms
• occurs within a single lineage

Question 7

Plate Tectonics

Answer 7

is the theory that the continents are part of great plates of Earth’s crust that essentially float on the underlying portion of the mantle

Question 8

Biogeography

Answer 8

is the scientific study of the past and present geographic distributions of species

Question 9

Exaptations

Answer 9

are structures that evolve in one context but become co-opted for other functions

Question 10

Evolutionary Trend

Answer 10

is a pattern of succession toward a particular characteristic in a group of related organisms

Question 11

Condition of Permian (oceanic & atmospheric)

Answer 11

• anaerobic bacteria could thrive in reduced oxygen environments and emitted H2S (poisonous metabolic by-product)
• higher global temperatures caused a drop in oxygen concentrations by reducing temperature difference between the poles and equator and slowing the mixing of ocean water
• reduced ocean oxygen is associated with the Permian mass extinction

Question 12

The Permian Mass Extinction (between Paleozoic & Mesozoic Era)

Answer 12

caused by extreme volcanism (which produced multiple environmental effects)

Question 13

Evidence suggests that life originated in which eon?

Answer 13

archaean

Question 14

Examples of adaptive radiation in organisms

Answer 14

• honeycreeper songbirds of the Hawaiian Islands
• Anolis lizards of the Caribbean
• Horses and deer in the post-dinosaur age

Question 15

Convergent Evolution

Answer 15

occurs when selective pressures produced by similar conditions favor the evolution of similar solutions
Ex. of similar conditions (habitat)

Question 16

Anolis Lizard ecomorph has long legs

Answer 16

• trunk/ground
• need long legs to jump from one brand perch to another

Question 17

How was the genetic relatedness of ectomorphs determined?

Answer 17

by comparing their mitochondrial DNA sequences

Question 18

The Evolution of Anolis Lizard in the Caribbean

Answer 18

the phylogeny of ectomorphs on a given island reveals that adaptive radiation has taken place

Question 19

What is the main selective pressure behind the evolution of different Anolis lizards species in the Caribbean?

Answer 19

specific ecological niches

Question 20

Different species evolve in response to

Answer 20

selective pressures created by specific ecological niches on the islands

Question 21

The evolution of different ectomorphs was what time of selection?

Answer 21

• example of disruptive selection
• each new ectomorph had characteristics that were ideal for a particular habitat
• these characteristics developed causing the lizards to lose the ability to survive effectively in the other habitats on the island

Question 22

How did some stickleback populations come to live exclusively in fresh water?

Answer 22

• some stickleback populations became trapped in lakes that formed at the end of the last ice age
• populations established when marine populations became trapped in the freshwater lakes where they migrated to spawn annually
• these lakes (formally connected to the ocean) were cut of by retreating ice fields

Question 23

What do different environments provide?

Answer 23

can provide different selective pressures on an organism’s morphology

Question 24

Why do some stickleback populations lack pelvic spines?

Answer 24

• in lakes with dragonfly larvae (pelvic spines can be a disadvantage) allowing the predatory larvae to grab the fish
• in lakes where there are no large predatory fish (there is no advantage to having pelvic spines)

Question 25

Geneticists

Answer 25

use crosses to map the location of genes

Question 26

Regulatory Regions

Answer 26

• presence of mutations that affect regulation of gene expression
• the gene remains intact but the location of its expression changes
• conveying a new phenotype without losing existing capabilities

Question 27

Line of Evidence in Stickleback Evolution

Answer 27

Genetic Evidence - reveals the precise molecular mechanism responsible for the change in the pelvic structures
Fossil Data - show a pattern of evolution over long stretches of time
Data - obtained by analyzing living fish in lakes show the selective pressures present in different environments
Morphological Changes - occur in the fossil record as in living populations (might deduce that the genetic mechanism discovered in the living populations might be responsible for the changes observed in fossils)

Question 28

Evolution

Answer 28

• repeats itself