Adaptation and change

2/12/2020

Adaptation and change

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Ecosystems and adaptation

We have an interdependent system of systems that we call the ecosystem

Each being is part of a trophic level: there are several hierarchical levels in an ecosystem.

https://www.nationalgeographic.org/photo/marine-food-pyramid-1/

Biosphere: the regions of the surface, atmosphere, and hydrosphere of the earth (or analogous parts of other planets) occupied by living organisms.

Abiotic Factors: non-living components of a biosphere

water
oxygen, air
sunlight
temperature
soil/rock/ sand

Biotic Factors: all living components of a biosphere from single celled beings an onward

Symbiosis: interaction between two different organisms living in close physical association, typically to the advantage of both.

https://ib.bioninja.com.au/standard-level/topic-4-ecology/41-species-communities-and/species-interactions.html

IT TAKES A LONG TIME FOR SPECIES TO ADAPT AND CHANGE

plant breeding has taken thousands of years
people have been farming corn for an estimated 12,000
the Earth is estimated to be about 4.5 billion years old

http://www.geologyin.com/2016/12/10-interesting-facts-about-geological.html

Stromatolites: are about 3.5 billion years old, calcareous mounds built of layers of lime-secreting cyanobacteria and trapped sediment, found in Precambrian rocks as the earliest known fossils, and still being formed in lagoons in Australasia. Stromatolites were originally formed by the growth of layer upon layer of cyanobacteria, a single-celled photosynthesizing microbe.

Prokaryotes: about 3.5 billion years ago, a microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles.

Prokaryotes include the bacteria and cyanobacteria.

How do we know how old fossils are?

Radiometric Dating: The use of radioactive isotopes as a measure for determining the age of a rock or fossil

Radioactive isotope: an unstable form of an element that decays into another element by radiation, that is, by emitting energetic particles

Half-Life: the amount of time it takes for one half of a substance to decay

Uranium-238: has a half life of 4.5 billion years

Potassium-40: has a half life of 1.3 billion years

Some Animals are finding ways to PHOTOSYNTHESIZE

Some animals have learned how to photosynthesize by adopting chloroplasts.

Aphids

https://phys.org/news/2012-08-evidence-photosynthesis-like-aphids.html

https://www.nature.com/news/photosynthesis-like-process-found-in-insects-1.11214

Sea Slugs

https://www.nationalgeographic.com/animals/2018/07/solar-powered-photosynthetic-sea-slugs-in-decline

Cyanobacteria: phylum of bacteria that obtain their energy through photosynthesis, and are the only photosynthetic prokaryotes able to produce oxygen.

Cryptobiotic (biological) soil crust: a living groundcover that forms the foundation of desert plant life.

This knobby, black crust is dominated by cyanobacteria, but also includes lichens, mosses, green algae, microfungi and bacteria.

When wet, Cyanobacteria move through the soil and bind rock or soil particles, forming an intricate web of fibers. In this way, loose soil particles are joined together, and an otherwise unstable surface becomes very resistant to both wind and water erosion.

The soil-binding action is not dependent on the presence of living filaments. Layers of abandoned sheaths, built up over long periods of time, can still be found clinging tenaciously to soil particles, providing cohesion and stability in sandy soils at depths up to 10cm.

Nitrogen fixation is another significant capability of cyanobacteria. Vascular plants are unable to utilize nitrogen as it occurs in the atmosphere.

Cyanobacteria are able to convert atmospheric nitrogen to a form plants can use. This is especially important in desert ecosystems, where nitrogen levels are low and often limiting to plant productivity. Soil crusts have other functions as well, including an ability to intercept and store water, nutrients and organic matter that might otherwise be unavailable to plants.

Nitrogen fixation is a process by which nitrogen in the Earth's atmosphere is converted into ammonia (NH3) or other molecules available to living organisms.

Nitrogen-fixing bacteria: are microorganisms present in the soil or in plant roots that change nitrogen gases from the atmosphere into solid nitrogen compounds that plants can use in the soil.

Nitrogen fixing bacteria: contain symbiotic bacteria called rhizobia within nodules in their root systems, producing nitrogen compounds that help the plant to grow and compete with other plants. When the plant dies, the fixed nitrogen is released, making it available to other plants; this helps to fertilize the soil.

Nitrogen fixation

https://en.wikipedia.org/wiki/Nitrogen_cycle

Endosymbiotic Theory

The endosymbiotic theory attempts to explain the origins of organelles such as mitochondria and chloroplasts in eukaryotic cells. ... From prokaryote to eukaryote

Mitochondria developed from proteobacteria, and chloroplasts from cyanobacteria