Biology- Macroevolution

Question 1

MacroEvolution

Answer 1

• large-scale evolutionary changes including the formation of groups of species (e.g. origin of mammals or flowering plants, not a single species)
• Explains evolution of millions of extinct and extant species from simple single-celled ancestors

Question 2

PROKARYOTES

Answer 2

(small, single celled organisms, whose cells lack membrane-bound organelles) around 3.5 bya.

Question 3

EUKARYOTES

Answer 3

(single or multicellular organisms, whose cells DO contain membrane-bound organelles) 1.5 bya, and multicellular life another several hundred million years later

Question 4

ABIOGENESIS

Answer 4

study of how life may have originated from simple organic compounds (organic compounds, the building blocks of life, can form under natural conditions, some RNA molecules can replicate independently)

Question 5

The history of Earth shows what?

Answer 5

The history of life on Earth shows increasing diversity of species (e.g. through divergent evolution), interrupted by several sudden mass extinction events (5 major ones)

Question 6

First example of mass extinction (Dinosaurs)

Answer 6

Dinosaurs evolved ~250 mya, and diversified into over 300 different species- were dominant carnivores and herbivores on land for over 100 my- went extinct ~ 65 mya (only surviving descendants are birds)

Question 7

Second example of mass extinction (Cambrian Explosion)

Answer 7

CAMBRIAN EXPLOSION, at beginning of Paleozoic era (542 mya) -relatively rapid evolution of most major animal groups and period of rapid diversification (40 my period)

Question 8

PACE OF EVOLUTION

Answer 8

2 theories to explain pace of evolution (both occur):

1. Gradualism
2. Punctuated Equilibrium

Question 9

GRADUALISM

Answer 9

new species appear very similar to the original species, and become increasingly distinctive over time (accumulation of small changes leads to large evolutionary changes) —SLOW AND STEADY

Question 10

PUNCTUATED EQUILIBRIUM

Answer 10

new species appear suddenly and show little change over long periods of time (rapids bursts of change followed by long periods of little or no change) —QUICK JUMPS
- More likely with major environmental changes and geographic isolation

Question 11

TRANSITIONAL FORMS

Answer 11

transitional forms. Fossils or organisms that show the intermediate states between an ancestral form and that of its descendants are referred to as transitional forms.

Question 12

CLADOGRAMS

Answer 12

• used to show the evolutionary relationships (PHYLOGENY) of different groups of species of organisms
• Like a “family tree”, where root of tree represents the ancestor, and the upper branches represent the descendants

Question 13

CLADISTICS

Answer 13

determining evolutionary relationships based on the presence or absence of shared unique characteristics

Question 14

DERIVED TRAITS

Answer 14

• traits that has evolved relatively recently, and passed down from ancestors
• not primitive traits

Question 15

What is believed about Organisms that share a recently evolved trait?

Answer 15

Organisms that share a recently evolved trait (SYNAPOMORPHY) are believed to be more closely related than organisms that do not share the trait

Question 16

Synapomorphy

Answer 16

Syn= shared 
Apo= derived 
Morphy= characteristics