Exam 2 Flashcards
4, 6, 8
How does competition impact each species?
negative impact
How do predation, parasitism, and herbivory impact each species?
negative impact on one, positive impact on the other
How does mutualism impact each species?
benefits both
What is competition typically over?
usually subtle, over food, water, space, shelter, mates, sunlight
How do effective competitors treat others?
exclude entirely or coexist
Resource partitioning
species adapting to feed on different versions of the same thing; using the same resource different ways
What benefits predators better at catching prey over other predators?
longer lives, better reproduction, better providers for offspring
Host
who parasites depend on and who may or may not die in the long run
What are the most common herbivores?
insects
How do plants ward off insects that feed on them?
produce chemicals, thorns, and attract insects that feed on harmful insects
Mycorrhizae
symbiotic relationships between fungi and plants, in which plants provide energy and protection and fungi help absorb nutrients from the soil
How do plants and pollinators benefit each other?
bees/birds/bats transfer pollen to ovaries that grow into fruits, consuming pollen or nectar as their reward
Food chain
linear series of feeding relationships
What do decomposers and detritivores do?
enhance top soil layers and recycle nutrients
How does the energy of higher trophic levels relate to that of lower trophic levels?
higher have about 10% of those below
How do numbers of organisms of higher trophic levels compare to those of lower trophic levels?
more organisms of higher trophic levels
How are food webs helpful?
to predict population changes
How do keystone species benefit populations?
balance them out, especially keystone species of higher trophic levels
Which trophic levels are most abundant?
lower trophic levels
When does primary succession happen in terrestrial sites?
bare rock/sand/sediment becomes exposed and the species that colonize the new substrate are pioneer species
Which pioneers are best suited to bare rock?
lichens (mutualistic fungi and algae)
How does secondary succession occur?
fire, followed by pioneer species, then pine forests, then hardwood forests (each outgrow the previous population)
How long do climax communities stay in place?
until disturbances restart succession
When do regime shifts/phase shifts happen?
due to loss of a keystone species, passage of crucial climactic threshold, invasion of a non-native species
When do introduced species become invasive?
when they leave behind predators and compete (limiting factors that previously regulated their population growth are absent)
How can invasive species be beneficial?
European honeybees help the economy and pollinate, some control pests
How can non-native species be beneficial?
increase biodiversity, help restore places devastated by human impact, provide resources for other organisms
What is the most effective way to prevent invasive species from taking over?
prevent their arrival
What do restoration ecologists do?
research historical conditions and either restore functionality of a system or return communities to their pre-settlement conditions
What does ecological restoration involve?
undoing human disturbance by reintroducing natural processes, removing invasive species, planting native ones, modifying landscapes to reduce erosion or influence water patterns
How does climate change affect the focus of restoration?
more focus on restoring function than restoring previous states
What are the determining factors of biomes?
temperature and precipitation
How are aquatic systems characterized?
temperature, salinity, dissolved nutrients, wave action, currents, depth, light levels, and substrate type, like biomes
Deciduous trees
lose leaves and remain dormant in winter
Coniferous trees
grow tall in temperate rainforests, creating a shaded/damp interior
What happens to temperate rainforests when when trees are cleared?
soil is susceptible to landslides/erosion
What negatively impacts tropical dry forest?
conversion for agriculture, so heavy wet season rains lead to soil loss
How much rain do deserts receive?
less than 25 cm of precipitation per year
How are fires in the summer in Chaparral/’Mediterranean’ regions helpful?
plants resist and can depend on the fire for germination of their seeds
Which was the first nation to implement population control policies?
India, now nearly the most populous country
How much does the global population grow per year right now?
over 80 million
What and when was the peak growth rate of the human population?
2.1% in the 1960s
What are the typical estimates for carrying capacity?
1-2 billion healthy or 33 billion impoverished
What other factors negatively impact the environment?
unsustainable resource consumption or degradation of ecosystems by pollution
What do demographers attempt to do?
predict population dynamics/environmental impacts
What determines a population’s environmental impact?
density, distribution, composition
Where are humans most populous?
temperate, subtropical, and tropical climates
What is today’s global median age, and what is the projected median age for 2050?
31 today, 36 in 2050
What causes infant mortality?
poor nutrition, disease, exposure to hostile environments, exposure to hostile elements (higher in pre-industrial countries)
What decreases total fertility rate?
industrialization, improved women’s rights, family planning, quality healthcare
What was Europe’s rate of natural increase in 2020?
-0.1%
How has average life expectancy increased in the last 50 years?
46 to 73
Frank Notestein
demographer who proposed the demographic transition, arguing that industrialization caused parents to invest in quality of life over family size
Demographic fatigue
some nations cannot make the demographic transition due to large populations, which make it hard to educate and employ young people
How many women worldwide age 15 to 49 reported using modern contraceptives in 2020?
55%
How many children can a typical woman have in her reproductive window healthily?
25
How is wealth distributed over the human population?
richest 1/5th have over eighty times the income of the poorest 1/5th and use 85% of the resources
What impact does one American have as opposed to in China, India, and Afghanistan?
one American equals two Chinese, six Indians, or eleven Afghans
When did humans pass the Earth’s capacity to support us?
1971 (we are now 50% beyond the Earth’s means)
Subspecies
populations of a species that occur in different geographic areas and differ slightly
How does habitat diversity contribute to species diversity?
flat areas have less biodiversity than structurally diverse areas like forests
Which family has the most species?
insects
Where is biodiversity greater?
near the equator, due to the solar energy, heat, and humidity
What happens when human disturbance replaces regionally unique habitats with homogenized disturbed habitats?
specialist species and species that rely on large expanses of habitat disappear, so species diversity decreases
Why are there so many species we haven’t found?
tiny species are overlooked, some organisms thought to be the same species turn out to be different upon close observation, humans haven’t explored some parts of Earth (like ocean depths)
How has food variety for humans changed throughout history?
7000 plant species and thousands of animal species throughout history, 15 crop species and 8 livestock species today
How much do pharmaceuticals from wild species (about half of pharmaceuticals) make per year?
$150 billion
What is the global economic value of seventeen major ecosystem services?
$155 trillion per year
Who is most vulnerable to human impact?
specialists who can only use specific resources, have trouble coping with change, reproduce slowly, and rely on mature/well-vegetated habitats
Where has most biodiversity loss happened?
tropical regions, due to deforestation
How many species that have ever existed are estimated extinct?
99%
What is the background extinction rate for mammals/marine animals?
1 species per 1-10 million per year
What is the current global extinction rate compared with the background extinction rate?
tens to hundreds of times greater
How many assessed species were reported threatened with extinction on the Red List in 2020?
27% of 120,000
What are the five primary causes of population decline/species extinction?
habitat loss, pollution, over harvesting, invasive species, climate change
How many of the world’s temperate forests/grasslands/shrublands had been converted for humans by 1950?
more than half
How much of the original Great Plains prairie habitat remains?
less than 1%
How much money does illegal global trade of wildlife make?
over $20 billion per year
Which species are most vulnerable to poaching?
large, long-lived, slow to reproduce species
How do conservation geneticists use the minimum viable population size?
to determine how vital it is to increase a population
Endangered Species Act
prevents destruction and trade of endangered or threatened individuals
How are endangered species cloned?
DNA is taken from the endangered species and inserted into an egg which is then implanted into a female of a similar species
How much has the land coverage of biodiversity hotspots decreased?
originally covered 15.7%, now cover 2.3% (which are still home to half of plant species and 42% of terrestrial vertebrate species)
How much of the world’s land area is protected as national parks, state parks, provincial parks, wilderness areas, biosphere reserves?
nearly 15%
What are some limitations to protected areas of land?
animals wander on and off national parks and shift toward the poles due to global warming
What portion of protected areas are managed using community-based conservation?
one quarter
