Cycle 11 Flashcards
______: Collection of individuals
Population
Original human population speciated from chimpanzees in central ____
Africa
________: Size per unit area
Population density
Is population density different in some parts of the world compared to others
yes
Factors that increase/decreased human population
Geographic range expands
Agriculture
Black Death The plague (decreased population)
Industrial Revolution - technological innovations, use of resources more effectively (HUGE increase)
The current human population (worldwide) is around __ billion
8.2
Populations grow if the rate of ____ (or immigration) is greater than the rate of ____ (or emigration)
births, deaths
_______ ______ models describe and predict how population size changes over time
Population growth
Per capita birth rate =
_____/_____
births per year (or new individuals entering the population)/population size
Per capita death rate =
_____/______
deaths per year (or individuals leaving)/population size
More births than deaths: r__0 (population grows)
r>0
More deaths than births: r__0 (population shrinks)
r<0
Per capita growth rate (r) =______ - _______
per capita broth rate - per capita death rate
Per capita growth rate is also called the ____ rate of increase
intrinsic
Humans, 2024 per capita: r - ______
0.009, or 0.9%
Faster per capita growth rates for organisms with _____ generation times (r is not constant among different species)
shorter
Ex: bacteria/single-celled organisms (shorter generation time, _____ values of r)
larger
Population growth models: ________ growth
Growth rate (dN/dt) = rN
Exponential
Does per capita growth rate change with population size?
Per capita growth rate doesn’t change with population size
The total growth rate accelerates as __ increases
N
__ can vary across habitats, over time, etc
K
Happens when conditions are ideal and resources are unlimited:
exponential growth
Population growth models: ____ growth
Eventually, resources become limiting and the population approaches its carrying capacity K
Logistic
Is exponential growth realistic?
NO
Adjusted for how close the population is to K
r x N x (K-N/K)
Per capita growth rate ______ as N increases
DECREASES
Carrying capacity (__)
K
Population growth curve =
r x population size (N)
The human population depends on:
Food
Water
Healthcare
Education
Contraceptive use
Economics
Culture
How do you think the human population will grow in the next 100 years? iclicker
Logistically
Two Environmental factors affecting population growth rates and size:
Density-dependent and
Density-independent
_______: (have more impact on large populations)
influence increases or decreases with changes in population density
Density-dependent
_______:
influence is the same on an individual regardless of population density
Density-independent
Density-dependent factors (examples)
e.g. intraspecific competition for resources
Plants growing at high density produce fewer seeds
An important principle in agriculture
Other density-dependent factors that regulate population size, besides intraspecific competition for food or space? (3)
-Parasites and communicable diseases
-Accumulation of waste or toxins
-Predation
Species that interact (eg predator and prey) each have a ______ effect on the other
density-dependent
Density-independent effects on population size examples:
Abiotic (non-living) component of the environment
extreme heat or cold
natural disasters (fire, hurricane, floods)
Biological, intrinsic factors: (4)
-fecundity (potential reproductive output)
-age of reproductive maturity, reproductive lifespan
-number of offspring produced per reproductive event
-number of reproductive events in an individual’s lifetime
Density-dependent and -independent factors can interact, give examples
Ex: extreme heat weakens health and increases susceptibility to disease
Ex: climate warming makes this rabbit more conspicuous to predators
average time between the birth of an individual and the birth of its offspring:
generation time
Bigger body organisms have a ____ generation time
longer
_____ and population growth
number of individuals of each age
If the age pyramid has a wider base (more younger individuals), the ____ population likely to grow
Age structure
faster
In humans, population growth & age structure are linked to _____ development
economic
Stage 1: Preindustrial
High birth rates/high death rates = population _______
does not grow
Stage 2: Transitional
High birth rates/low death rates (decreases first) = population ______
grows
Very rapidly
Stage 3: Industrial
Both birth rates and death rates are relatively ___
low
Stage 4: Postindustrial
Birth rates continue to decline, death rates don’t decline anymore so the population ______
decreases
Which of the following is a factor contributing to the continued growth of the human population? iclicker
1. We have expanded our geographical range.
2. We have increased our carrying capacity by introducing agriculture.
3. Advances in public health have reduced the density-dependent effects of disease.
4. We have had more time than other species to evolve more successful adaptations to the environment
1,2,3
Humans have big impacts on other species: Extracting and controlling resources and
______ impacts (pollution, climate change)
Environmental
IPAT framework
Impact =
population size x Affluence x Technology
The wealthiest populations, not necessarily the largest populations, have the biggest effect on:
the environment
Humans are predators and ______
competitors
Humans modify the ______
Effects carrying capacity
landscape
Human activities change the _____
climate
Humans cultivate some species for ____
food
Only __ of the combined weight of mammals on Earth is wild
6%
Humans try to conserve: re-introduce ______ species back to their historic range
threatened
Biological control: introduce a ____ species to an area to control a local pest
new
Population interact in different ways (_______ interactions), with different effects on each party
interspecific
_____, _____, _____: +/-
Natural enemies
Predator/herbivor, parasites gets nutrients
Prey/plant/host is killed, injured or weakend
Predation, herbivory, parasitism:
______: -/-
Both competitiers lose some resources
Would do better if other one is not there
Competition
______: +/+
Both benefit from interacting with the other
Mutualism
Commensalism: +/0
One party benefits, one is unaffected
_______: -/0
One party is harmed, one is unaffected
Amensalism
Many interactions are ______ (organisms live on or in another)
symbiotic
_____ interactions can include paratism, mutualism, commneslaism
Symbiotic
Which of the following types of interspecific interactions benefit BOTH species involved iclicker
Mutualism
Population whose fitness is influenced by another population evolve adaptations to improve their ability to interact with the other
______and evolutionary ______
Coevolution and arms races
Which type of inerspecific interaction is LEAST likely to result in coevoltuon iclicker
Commensalism (both speaisces arnet affected)
Humans are part of the earth’s ___ webs and ecosystems
food
______ (human-made arifticats) will eventually transform into geological layers
Technofossils
Increaisng effect on ecosystems (orgnaisms and their physical enviorment) EX:
Technofossils (human-made arifticats) will eventually transform into geological layers
Climate warming and reduced sea ice
Rising levels of greenhouse gas (eg CO2)
Ocea acidifctiaon
Rising sea levels
______: A new geological period, dating from around 500 to 70 years ago, due to human atcivties fundamentally changing Earth’s climate and ecosystems
Anthropoecne
Rate of extinction is very ___ now
fast
Is Anthropocene inevtiable?
NOT inevitable (mabe now that w eknow, we can prevent it)
In the Anthropocene, humans are the main drivers of environmental change. How can we better regulate our effects on Earth’s systems and biodiversity?
To maintain or improve human quality of life without further cost to the environment, need cooperative, interdisciplinary research and initiatives.
Ecology, medicine, engineering, ethics, law, physiology, math, sociology, politics…
Which of the following correctly describes the Anthropocene? iclicker
A. It is proof that a sixth mass extinction event is inevitable.
B. It is defined as having started in the year 2000.
C. It will be definitely be known as a geological period of predominantly negative human impacts on Earth’s systems.
D. It will be identifiable in rock layers of the future by the abundance of technofossils.
c
