Study Guide 11 HoL Conservation Flashcards
Put the events below in the order in which they occurred in Earth’s history.
a. The origin of life on Earth
b. The evolution of C3 photosynthesis
c. The evolution of C4 photosynthesis
d. The colonization of land by early tetrapods
e. The development of fossil fuels (oil, etc)
f. Mass extinction
a. The origin of life on Earth
b. The evolution of C3 photosynthesis
d. The colonization of land by early tetrapods
e. The development of fossil fuels (oil, etc)
c. The evolution of C4 photosynthesis
(F happens several times throughout history)
The diagram below shows the O2 levels in the atmosphere throughout Earth’s history. Important biological events are labeled
a)photosynthesis evolved after the first evidence of life. if they were not photosynthetic, how did the first organism obtain sugar for respiration?
Early organisms performed chemosynthesis, which is a process by which energy rich carbon compounds are broken down for energy (instead of using sunlight)
The diagram below shows the O2 levels in the atmosphere throughout Earth’s history. Important biological events are labeled
b) the first evidence of aerobic respiration occurs about 2 billion years ago. why did aerobic respiration arise after photosynthesis? if the first living organism were not aerobic, how were they able to perform respiration?
Aerobic respiration arose after photosynthesis because there wasn’t enough O2 in the atmosphere for it to be efficient. Before that, organisms used anaerobic respiration or fermentation.
The diagram below shows the O2 levels in the atmosphere throughout Earth’s history. Important biological events are labeled
c)why do we see an increase in O2 levels following the invasion of land? what was the terrestrial landscape like at this time?
Colonizing land provided a vast new habitat for plants. Shortly after, during the Carboniferous period, Earth was covered with gymnosperm forests, and atmospheric oxygen levels were at their highest in Earth’s history.
The diagram below shows the O2 levels in the atmosphere throughout Earth’s history. Important biological events are labeled
d)why do O2 levels drop so significantly ~250 mya? why do we not see similar drops 44 mya, 359 mya, 201 mya, or 65 mya?
O2 levels dropped significantly at 250 million years due to the end-Permian extinction, which wiped out Carboniferous forests. Other extinctions had less impact on plants, or plants recovered faster than animals, so O2 levels didn’t drop noticeably.
the graph below shows the total number of genera (y axis) on Earth from ~540 million years ago to today (x axis)
a)the largest increase in genera is seen in the recent past, since the end of the Cretaceous period. why then is the Cambrian period considered an ‘explosion’ of life?
The Cambrian is called an “explosion” of life because animal diversity rapidly increased, with many current phyla first appearing. Key behavioral changes, like predation, also emerged, marking critical evolutionary shifts, even though recent diversification rates are higher.
the graph below shows the total number of genera (y axis) on Earth from ~540 million years ago to today (x axis)
b)what is the overall pattern in the figure? what does this indicate about the resilience of life on earth?
The overall pattern shows an increase in diversity, despite losses during extinction events. It resembles an exponential growth curve, suggesting that survivors of mass extinctions can recolonize and repopulate, as Ian Malcolm said, “Life finds a way.”
describe how the diversification of angiosperms in the Paleogene influenced the terrestrial environment and the diversification of other taxonomic groups.
Angiosperms influence biogeochemical cycles through increased transpiration, photosynthesis, and nitrogen cycling with Rhizobia. They also create niches for nectar feeders and fruit-eaters, driving the radiation of species that depend on them.
what is the anthropocene?
The Anthropocene is not an official geological time period but was coined by anthropologists to describe when human impacts began shaping the global environment. Proposed start dates include the Industrial Revolution (~1750 AD), the rise of agriculture (~10,000 years ago), or the evolution of Homo sapiens (~300,000 years ago).
given an example of the following responses to environmental change driven by human
a)move
Climate change shifts species’ geographic ranges as their fundamental niches move to new locations. For example, many species are moving poleward to follow their temperature niches.
given an example of the following responses to environmental change driven by human
b) acclimate
Plastic traits can track environmental shifts. For example, great tits adjust egg-laying dates to match moth larvae emergence, showing plasticity. Similarly, many ectotherms can adjust thermal tolerance based on current temperatures, helping them survive future heat waves.
given an example of the following responses to environmental change driven by human
c) adapt
Hunting pressure on African elephants has led to an increase in alleles for tuskless phenotypes as an adaptation to human-induced environmental changes.
given an example of the following responses to environmental change driven by human
d) die
“die” refers to loss of fitness, which can cause population declines. For example, hunting caused a dramatic decline in sea otter populations, leading to increased urchin densities and kelp forest decline.
how do the following human activities drive evolutionary change in other species?
a) hunting/fishing
Humans’ preference for larger organisms often selects for smaller individuals, less impressive ornamentation (like elk racks), and earlier sexual maturity.
how do the following human activities drive evolutionary change in other species?
b) use of pesticides/herbicides/antibiotics
Use of these chemicals increases the degree to which pests are resistant to the chemicals
