Biology Of Organisms Chapter 25 Outline

Front 1

Macroevolution

Back 1

Change in the genetic make-up leading to the appearance of major evolutionary developments.
Ex. Development of wings and feathers

Front 2

Protobionts

Back 2

Aggregates of abiotically produced molecules surrounded by a membrane-like structure.

Front 3

Characteristics of protobionts

Back 3

a) Able to maintain a unique internal chemical environment
b) Capable of metabolic activity
c) Able to reproduce

Front 4

Two key properties of all living organisms

Back 4

a) Carry out metabolism
b) Able to accurately reproduce

Front 5

Liposomes

Back 5

Small, membrane-bound droplets that form when lipids or other organic molecules are added to water.

Front 6

Characteristics of liposomes

Back 6

a) Conducts voltage across its membrane
b) Conducts osmosis across its membrane
c) possesses a lipid bilaye

Front 7

Characteristics of RNA

Back 7

a) Protobionts with RNA could pass RNA onto
successive generations through division
b) Through natural selection, DNA could evolve
And RNA could settle into its current role
c) RNA probably evolved before DNA

Front 8

Ribozymes

Back 8

RNA molecule capable of catalyzing a chemical reaction
i) Makes copies of short pieces of RNA
ii) Remove nonsense segments
iii) Makes molecules fully functional

Front 9

Stratum

Back 9

layer of rock or soil with internally consistent characteristics that distinguishes it from other contiguous layers

Front 10

Index fossils

Back 10

fossils used to correlate strata in various locations world wide
a) Strata can be subjected to erosion resulting in poor data
b) Order of strata with index fossils can be determined, but not their age
c) Various methods exist for dating fossils depending on approximate age of fossils

Front 11

Radioactive dating

Back 11

time measurement based on decay of radioactive isotopes; each isotope has a fixed rate of decay.

Front 12

Half-life

Back 12

amount of time it takes for 50% of the original sample to decay (unaffected by temperature, pressure, and other environmental factors).

Front 13

Carbon 14

Back 13

found in living organisms which begins to decay at the time of the organisms’ death
-Only accurate in dating organisms that existed 75,000 years ago or sooner

Front 14

Potassium 40

Back 14

Found in rocks which decays to Argon 40, becoming trapped in the rocks
-Has a half-life of 1.3 by and is accurate in dating organisms that existed millions of years ago.

Front 15

Magnetic reversals

Back 15

occurs when earth’s N/S magnetic fields flip-flop
1) Iron particles in lava or sediment, align themselves with earth’s magnetic fields, becoming locked in place when the substrate hardens
2) Affects the entire planet allowing for global comparison

Front 16

Stromatolites

Back 16

rock-like structures composed of multiple layers of bacteria and sediment
1) Among the oldest fossils on earth (3.5 billion years ago)
2) Present day, found in warm, shallow, salty bays

Front 17

Photosynthesis & Oxygen Revolution

Back 17

1) oxygen produced by photosynthetic prokaryotes, became dissolved in water
2) As oxygen saturated the surrounding water, it escaped and began to fill the atmosphere
3) The oxygen content of the atmosphere increased from 2.7 – 2.2 billion years ago
4) photosynthetic prokaryotes were the only inhabitants on earth from 3.5 – 2.0 billion years ago
5) cyanobacteria (blue-green algae) are the only living photosynthetic prokaryotes
6) with the advent of oxygen, many anaerobic prokaryotes died out.
7) once oxygen entered the atmosphere, oxygen levels increased rapidly
8) this rapid increase of atmospheric oxygen was due to the evolution of photosynthetic eukaryotes
9) with the presence of oxygen, aerobic cellular respiration began to occur

Front 18

Eukaryote Evolution

Back 18

1. The first eukaryotic cells appeared 2.1 billion years ago
2. Eukaryotic advancements over prokaryotes included a nuclear envelope (nucleus) along with many complex organelles

Front 19

Endosymbiosis

Back 19

close association of two species in which one lies inside another

Front 20

Mitochondria

Back 20

aerobic heterotrophs

Front 21

Chloroplasts

Back 21

aerobic autotrophs

Front 22

Endosymbiosis

Back 22

close association of two species in which one lies inside another

Front 23

Multicellularity

Back 23

a) Multicellularity evolved 1.5-1.2 billion years ago
b) Unicellular eukaryotes evolved into colonial eukaryotes which evolved into multicellular eukaryotes

Front 24

Cambrian Explosion

Back 24

1) Most major phyla of animals appeared during the Cambrian period, 535-525 million years ago
2.) poriferans (sponges), cnidarians (corals, jellyfish, sea anemones), and mollusks (clams, squids, snails) predate the Cambrian period

Front 25

Colonization of Land

Back 25

plants, fungi, and animals began colonizing land 500 million years ago and had to overcome the following challenges:
a) dehydration
b) terrestrial reproduction
c) terrestrial locomotion

Front 26

Rise and Fall of Dominant Groups

Back 26

750-500 million years ago glaciers covered earth’s land masses from pole to pole and the oceans were iced over

Front 27

Continental Drift

Back 27

the movement of tectonic plates over time

Front 28

Continental Drift

Back 28

250 million years ago the supercontinent Pangaea formed
a) the continent’s interior was cold and dry
b) surrounding oceans were deep
2. 180 million years ago Pangaea began to break up and drift apart resulting in localized experiments in evolution
3. Pangaea’s break up led to extinctions which resulted in new opportunities for survivors

Front 29

Mass Extinctions Causes

Back 29

a) Volcanic activity
b) Extraterrestrial bolus
c) Climate change

Front 30

Extinction

Back 30

death of all members of a species

Front 31

Mass extinction

Back 31

global extermination of large numbers of species

Front 32

Two Major Mass Extinctions

Back 32

Permian extinction
a) wiped out 96% of all marine species
b) Probable cause: enormous volcanic eruptions in present-day Siberia
2. Cretaceous extinction
a) Wiped out 50% of all marine species as well as the dinosaurs
b) Probable cause: large asteroid (at least 10km) impacting off the Yucatan Peninsula

Front 33

Adaptive radiation

Back 33

period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill vacant ecological niches in their new communities

Front 34

Probable cause of Cretaceous extinction

Back 34

large asteroid (at least 10km) impacting off the Yucatan Peninsula

Front 35

Heterochrony

Back 35

evolutionary change in the timing or rate of an organism’s development
Ex. Human v. chimpanzee

Front 36

Evolutionary Effect of Genes

Back 36

1) Heterochrony: evolutionary change in the timing or rate of an organism’s development
i. Ex. Human v. chimpanzee
2) Differential growth rates in humans
Ex: Newborn, growth to adult evolving pelvis stages and head
3) Paedomorphosis: retention of juvenile fetures in adults from evolutionary ancestors
i. Ex. Gills in Axolotl
4) Homeotic genes: any of a group of genes that regulate the overall body plan of organisms by controlling their early developmental fate of groups of cells. Highly conserved throughout evolution.

Front 37

Paedomorphosis

Back 37

retention of juvenile fetures in adults from evolutionary ancestors
Ex. Gills in Axolotl

Front 38

Homeotic genes

Back 38

any of a group of genes that regulate the overall body plan of organisms by controlling their early developmental fate of groups of cells. Highly conserved throughout evolution.

Front 39

Evolutionary Novelties

Back 39

1. Eyes: complex for more advanced organisms while simpler for less advanced organisms; multiple uses
2. Avian bones and feathers: fossil record indicates uses of pneumatic (air-filled) bones and feather other than flight

Front 40

Eyes

Back 40

complex for more advanced organisms while simpler for less advanced organisms; multiple uses

Front 41

Avian bones and feathers

Back 41

fossil record indicates uses of pneumatic (air-filled) bones and feather other than flight