Life Processes

Question 1

history of life on Earth

Answer 1

began about a billion years after Earth came into existence photosynthesis allowed the oxygen-rich atmosphere that was necessary for the explosion of life, chemical evolution (formation of early crust and atmosphere, small organic molecules in the seas, large organic molecules start forming, first protocells form), biological evolution (single-cell prokaryotes form, single-cell eukaryotes form, led to a variety of multicellular organisms)

Question 2

biodiversity is facilitated by:

Answer 2

• variable env conditions (Earth’s variability in time and space allowed new and diff landscapes, abiotic and biotic limiting factors and selecting pressures exist (like light, water availability, nutrients, moisture, temps) challenge species)
• genetic variability (differences in tolerances to stress)
• differential survival and reproductive success (speciation, extinction)
• geographic ranges, habitats, and niches (envs present barriers to species from moving from place to place, dispersal, adaptation)

Question 3

Lamarck’s theory of evolution

Answer 3

proposed evolution by acquired characteristics (learning how to adapt to diff envs)

Question 4

Darwin and Wallace’s theory of evolution

Answer 4

proposed natural selection as the mechanism of evolution (organisms struggle to survive and reproduce, produce more offspring than can survive, individuals vary genetically, and some fit their env better and survive which creates differential reproductive success and increases gene frequency in the pop)

Question 5

mutation

Answer 5

accidental and random changes in DNA that may be passed onto subsequent generations, provides a new trait/appearance that can either help it survive or have a lesser change of survival/reproductive success

Question 6

phenotype

Answer 6

observable expressions of an organism’s genotype, trait associated with the genes

Question 7

biological evolution

Answer 7

genetic changes in pops of organisms across gens, can be random or direct by selection, can be divergent, convergent, or co-evolution

Question 8

selection

Answer 8

mechanism by which the frequency of traits change in a pop, non-adaptive traits decrease survival while adaptive ones enhance survival and reproduction, traits are selected as being beneficial or detrimental and, over time, the beneficial ones are inherited and become dominant

Question 9

specialization

Answer 9

some species have adapted to specific env characteristics since organisms differ in tolerance for variation in limiting factors, stresses over time can be a limiting factor that kills the pop off or force them to adapt

Question 10

types of selection that causes variability

Answer 10

• directional: one extreme doesn’t work while the other works well, so one species genetically migrates towards the latter trait
• stabilizing: narrows the range of traits to choose the median that provides the most benefit
• disruptive: takes the regular distribution and divides it into diff traits that are beneficial in diff envs, splits the species into two which increases diversity

Question 11

biodiversity

Answer 11

the number of individual species found within certain envs

Question 12

speciation

Answer 12

the process of generating new species, a single one can generate multiple new species

Question 13

types of speciation

Answer 13

• allopatric: results from the physical separation of pops which allows both pops to evolve separately
• sympatric: organisms become reproductively isolated within the same geographic range, two species evolve enough away from e/o to not be able to reproduce together

Question 14

genetic diversity

Answer 14

individuals in a species vary genetically from one another, provides building blocks for subsequent gens which can change into diff forms, fueled by high pops (low pops result in increasing vulnerability to extinction and genetically similar parents produce less viable offspring)

Question 15

species diversity

Answer 15

the number of species in a biotic community, varies according to habitats, speciation generates new species and adds to species richness (biodiversity), low biodiversity is likely due to more stresses and limiting factors while high biodiversity is likely due to less stress

Question 16

extinction

Answer 16

elimination of species and reduction of species richness

Question 17

causes of extinction

Answer 17

• lack of genetic diversity that produces less viable offspring
• catastrophes
• loss of habitat and food supply
• climate change
• disease
• invasive species and better adaptations create competition for resource

Question 18

ecosystem diversity

Answer 18

the number and variety of biotic communities within ecosystems, landscape variability and disturbance regimes (disturbances cause the system to change and allows new genetic developments, niches, and habitats) tend to promote higher levels of biodiversity

Question 19

biogeography

Answer 19

analyzes the concentration of species and similar species in certain areas, biodiversity is unevenly distributed due to env gradients (diff types of and variations in habitats like temp across the globe), species diversity decreases towards the poles and increases towards the equator and tropical regions

Question 20

key factors in biogeography

Answer 20

• temp gradients: most species are adapted to survive at specific temps, species intolerant to cold temps won’t thrive in cold envs
• altitude: diversity decreases with altitude since the density of air decreases which lessens the amount of O2
• moisture: water is important and critical as a limiting factor, plentiful supply will sustain a high biodiversity while limited supply will only be able to sustain low biodiversity, diversity decreases with dryness
• Light: less available light is not able to sustain a high number of species in comparison to areas with plenty of light

Question 21

geographic range

Answer 21

spatial extent of a species habitat, limited by physical barriers like oceans, mountains, and other features like moisture and temps

Question 22

habitat

Answer 22

where a species is able to live within its range, range where a species can survive and be found; oceans

Question 23

ecological niche

Answer 23

includes biotic interactions and functional roles in biotic communities, related to the specific functions and interactions between a species and its habitat

Question 24

interactions between species

Answer 24

based on roles and links in food webs, relationships may not always be beneficial and can act as limiting factors, and are integral to the adaptation process

Question 25

types of interactions

Answer 25

• interspecies competition: whenever there are resources that appeal to several species, there is a competition to acquire them
• mutualism: both species benefit from the relationship (ex. clownfish hide in anemone, feed on its dendrites)
• predation/herbivory: species feeding off of other species which forms a food chain/web, relationship can change based on pops of certain species
• commensalism: a species benefits from the relationship while the other experiences no effect (ex. whales are unaffected by barnacles while the latter use the whale as a source of transportation)
• parasitism: one species benefits while the other suffers (ex. mosquitoes and ticks)
• amenalism: one species suffers while the other is unaffected (ex. mold is unaffected but a person living in a contaminated env is exposed to health problems)

Question 26

niches

Answer 26

diff locations in which diff species can thrive, resource/niche partitioning reduces competition and niche overlap, which increases biodiversity, filling of ecological niches in the same habitat creates species richness in a community

Question 27

ecological succession

Answer 27

progression of species that occupies a habitat over time, initially included a linear progression thru seral stages towards a climax biotic community, adds to biodiversity by creating a mosaic of serial stages

Question 28

primary succession

Answer 28

follows severe disturbances (ex. ice ages, volcanic eruptions), resets the landscape, allows pioneer species to move in, soil formation, biotic communities change over time in response to env developments

Question 29

secondary succession

Answer 29

follows degradation or light disturbances, provides basic materials so there is more to build upon, generally faster than primary succession

Question 30

promotors of biodiversity

Answer 30

• middle stages of succession (things change the most in the middle of rebuilding a habitat)
• moderate env disturbance (frees up niches for other species)
• small changes in env conditions
• evolution

Question 31

inhibitors of biodiversity

Answer 31

• extreme env conditions (like c.c.)
• large env disturbances (catastrophes)
• intense env stress (like long periods of hot and cold weather)
• severe shortages of key resources (loss of materials)
• non-native species introduction (invasive species that compete with existing species)
• geographic isolation (some species can’t migrate quickly enough out of the endangered habitat)

Question 32

human impacts on biodiversity

Answer 32

human pop growth leads to increased consumption and reduced resource efficiency, primary drivers include: habitat loss, invasive species, overexploitation, pollution, c.c. and global warming