Final BIO122 Flashcards
Ecology
Study of how organisms interact with each other and their environment. Both biotic and abiotic.
Biotic
How organisms interact with each other.
Interspecies vs intraspecies interactions.
Interspecies
- Predator/prey interactions
- Competition with other species
Intraspecies
- Mating behavior
- Herd dynamics
- Distribution
- Competition within the species
Abiotic
How organisms interact with physical factors.
Physical factors influence attributes of a species.
Some hierarchical levels of life:
Global ecology, landscape ecology, ecosystem ecology, community ecology, population ecology, organismal ecology.
Example: Global ecology - How are ecological changes altering Earth?
How has ecology had a great influence over our understanding of evolution?
Considering aspects of ecology (i.e. competition) led to the theory of natural selection.
Why do organisms live where they do? (Population level question)
- Interactions with the environment shape organisms through natural selection.
Organisms might live in an area because they have spent many generations adapting to that environment. - Migration can bring organisms to new environments.
Organisms might live in an area that they migrate to and are “pre-adapted” for.
What determines the structure of an ecosystem? Top-down vs bottom-up (community level question).
Top-down: The abundance of apex predators determines the structure of the ecosystem.
Bottom-up: The amount for primary production (plant-growth) determines the structure of the ecosystem.
What determines how diverse an ecosystem is? (Ecosystem level question)
Tropical regions have more biodiversity than anywhere else on earth.
Polar regions have very little biodiversity.
Abiotic - extinction is less likely to happen in tropics bc rainfall and the terrain is variable.
Biotic - By chance the tropics became biodiverse and since have maintained bc of frequency of ecological interactions between species.
____ and ____ establish abiotic factors on earth.
Geology, physics
What establishes regional climate patterns?
Solar radiation.
How do seasons come about.
Seasons result from the earth’s rotation being offset from the angle of its orbit around the sun.
Tropics receive more or less sunlight year round.
How does local geology also alter climactic conditions?
Prevailing temperature, wind, and precipitations set the overall climate of a region.
Mountain ranges, bodies of water, or other features of geology can alter that climate.
Proximity to water influences…
Terrestrial Climate
What are terrestrial ecosystems mostly determined by?
Annual temperature and rainfall.
Movement of air leads to rainfall and temperature regimes for a region.
____ factors establish climates.
Abiotic
Marine ecosystem types are established by…
Availability of light and nutrients.
Very little organic matter is present deep in the ocean because…
Lack of nutrients and sun light.
Most organisms are dependent on matter that “rains down” from above.
Some deep-water ecosystems are dependent on geochemical energy.
What is behavior?
The study of how animals respond to their environment.
Includes everything from reflex movement to personality traits.
What are the four questions to thoroughly understand a behavior?
Proximate Questions: Who/what/how of a behavior (mechanistic understanding)
1. What mechanisms trigger a specific response?
2. How does the expression of a behavior develop as the animal matures?
Ultimate Question: Why of a behavior (evolutionary significance)
3. What is the ecological function of the behavior and how does it aid survival and reproduction?
4. How did the behavior evolve?
Imagine you are studying pack hunting behavior in wolves. If you asked the question: “Is pack hunting adaptive?” - Would that be a proximate or ultimate question?
a. Proximate
b. Ultimate
Ultimate
Beware of the adaptationists explanation…
Interpreting the evolution of a character by interpreting its function assumes the character evolved through adaptation, which often leads to just-so stories.
Innate behaviors are ____, ____, or ____.
fixed, hardwired, reflective.
Example of innate behavior..
Spiders that weave webs are born knowing how to weave a web.
Innate behaviors are often linked to…
survival
Do humans have innate behaviors?
Yes, reflexive
Innate behaviors are usually…
genetic traits.
Snakes that eat slugs innately have…
different odor receptor alleles.
Snakes in populations that have banana slugs will instinctively eat banana slugs from birth.
Snakes in populations without banana slugs will not eat them.
Is a behavior the result of genetics or the environment?
Can be both
Nature vs nurture tested with mice.
Mice mimic the behavior of the mice that raised them indicating gene expression changes in brains of fostered mice.
Can honeybees behavior vary depending on the evniroment?
Yes.
Honeybee behavior is determined by juvenile hormone but can vary depending on environment.
Types of learning behavior:
Imprinting
Cognition
Spatial
Associative
Social
What is learning?
Changing a behavior due to experience.
Most animals can learn some behaviors.
Do learned behaviors change with experience? What is a critical period which birds can learn who their parents are?
Yes
Imprinting
Critical period - a period of an organism’s life when it can learn a particular behavior.
Can imprint any object so long as it moves and makes noise (baby chickens).
Parental imprinting of offspring can be exploited…
- Several bird species lay eggs in the nests of other species (birds as nest parasites).
- Chicks may have innate behaviors that kill the true offspring.
- Chicks may be able to outcompete the true offspring by growing faster.
Navigation can involve a ____ map, and/or a ____ map.
spatial, cognitive
Spatial - memorizing relative locations.
Cognitive - Allows for adjustments because it is based on relative position.
Associative learning occurs when…
two stimuli are linked
Association A = B
Social learning involved ____ and ____.
observation, imitation
Predator tactics are likely learned from mothers by observation.
Is social learning necessary for human culture and brain development?
yes
Oxana Malaya abandoned by parents at 3 years old raised by dogs, acted like a dog instead of a human.
What likely explains the existence of language?
Social learning.
Dif animals make calls for predators, babies make wrong call and are corrected.
Experimental design to test cognitive ability.
Color code or pattern code a maze with reward at end to reward recognition of a stimulus.
Altruism
Behavior that lowers the fitness of the individual but increases the fitness of the group.
Altruism evolves in situations where…
Individuals are not as successful as groups.
Why is altruism higher in ground squirrels when relatives live near by?
Improving the fitness of close relatives likely improves the chances that some of your genes will be transmitted to next generation.
Alarm calls help squirrels avoid predators, but squirrels who make the alarm calls are more likely to be located by the predator.
What is population ecology?
The study of how and why populations change.
How big is a population?
A population includes all of the organisms of a specific species that live in a defined area.
Density is a good way to estimate population size (individuals/units are or volume).
Why does the different population distributions matter, and what are they?
To help determine population size it is important.
Clumped
Uniform
Random
Is population density negatively correlated with body size?
yes
What causes the size of a population to change?
Birth
Death
Immigration
Emigration
Is the rate of mortality the same across an organisms life?
no
What do survivor curves show?
Different life strategies for cohort survival
Type 1 - Most individuals live for a long time.
Type 2 - Equal chance of death at all life stages.
Type 3 - High mortality early in life.
Rate of growth equation
G = rN
Do populations recovering from significant loss often show exponential growth for a while?
yes
Carrying Capacity
Maximum number of individuals that a location can support.
Birth and death rates are equal.
Logistic model of population growth
dN/dt = r_instN(K-N/K)
K = carrying capacity (size of population that can be supported)
Incorporating carrying capacity into growth model does what?
Acts to slow down growth rate as population increases (approaches K.
When is population growth the fastest under the logistic growth model?
In the middle
Why does growth in real populations decrease when they approach carrying capacity?
Lack of food, increased predation, disease spreads easier.
What caused our species to undergo exponential growth?
Advances in agriculture and medicine.
What is community ecology?
The study of how populations interact with each other.
What is an organism’s niche?
What biological and abiotic components of its habitat it uses.
Resources - food, water…
Climate - What temp a species can tolerate.
Time - When a species is active, when it mates.
Interactions - What other community members the species interacts with.
Boom and bust cycle
Many predator-prey systems follow this.
What influences a boom and bust cycle?
Parasites can influence population size.
Vegetation, if the population gets too large and they eat up everything then starve.
Examples of species-species (interspecific) interactions.
Mutualism - Both species benefit.
Predation, Herbivory, Parasitism - One species benefiting and another species harmed.
Competition - Harms both species.
Why is competition between species generally bad for both species?
When individuals compete for the same resources, either reaches its maximal fitness.
Which two ways can competition between species be resolved?
Extinction and niche partitioning.
Competition - Surviving species occupies the entire niche.
Partitioning - Competition is reduced based on less interaction - likely results in character displacement through evolution.
Predator carrying capacity is determined by…
Prey population
Predator-prey relationships may result in…
Evolutionary arms race.
Diversity is species abundance and species richness. Which is more diverse, Community 1 or Community 2?
A. Community 1: A - 25%, B - 25%, C - 25%, D - 25%
B. Community 2: A - 80%, B - 5%, C - 10%, D - 5%
A. Community 1
Community 1 is more diverse because species abundance, both communities are equally rich (same number of different species).
Do ecosystems change over time?
Yes
Ecological succession
The change in an ecosystem over time.
Pioneer species
Modify the ecosystem and make it habitable for additional species.
Which type of organisms form the basis of most ecosystems?
Photosynthetic organisms.
Trophic levels
Trophic levels refer to where in a food chain an organism is.
Producers are photosynthetic and are the base of the food chain.
Consumers eat producers or other consumers.
Does biomass increase or decrease in the upper levels of food chain?
Decreases dramatically.
Most calories gained from eating do not result in growth.
Energetic hypothesis - food chains are short because energy transfer between trophic levels is inefficient.
Biomass decreases diagram
Producers (10kcal) -> Primary consumers (1kcal) -> Secondary consumers (100cal) -> Tertiary consumers (10cal)
There are fewer “apex predators” than prey items - supports the energetic hypothesis.
In the mid 1800s what allowed farming to become industrialized? Why did farming become industrialized?
Mechanical Innovation
To keep up with the human demand for food
Agriculture ____ diet diversity but ____ stability.
reduced, increased
What doubled the meat production since WW2, which most of the world follows?
CAFO model
Concentrated Animal Feeding Operations
Has animal welfare and environmental costs.
Traditional livestock production vs the CAFO model
Traditional:
- Crops and livestock grown together.
- Mostly sustainable because production was small and ecosystem could manage the rate of waste production.
CAFO:
- High number close quarters, where livestock are fed and housed.
- Crops for feed area grown elsewhere and transported to the CAFO
- Waste is produced faster than the local ecosystem can sustain
What are the tradeoffs of CAFO?
Greenhouse Gas Emission:
- release nitrous oxide (296x more potent than CO2)
- Animals release methane (21x more potent than CO2)
- Agriculture accounts for 70% of the water use world wide, 70% of the agricultural output is devoted to feeding livestock.
What is the major tradeoff with CAFOs?
Massive production of animal waste as a byproduct.
What does agricultural and CAFO runoff?
Eutrophication of waterways.
When is meat consumption projected to double?
1999-2050
Per capita meat consumption in developing countries doubled between 1980 and 2002.
Why (ecologically) does it take more resources to eat meat than to eat vegetables?
Feed Conversion Efficiency: Livestock animals require large amounts of plant-based feed to grow.
Water Usage: Livestock farming requires vast amounts of water for the animals to drink and for growing their feed crops.
Land Use: Raising animals for meat consumption requires a substantial amount of land for grazing and growing feed crops.
Significant challenge for humans:
Global climate change, human population growth, and loss of biodiversity.
In the middle is food production and clean water.
Are species and ecosystems disappearing?
Yes
Most places of conservation concern are in relatively poor countries.
Why do species go extinct?
Habitat loss, climate change, invasive species interactions, pollution.
What does overexploitation of a habitat (habitat loss) cause? Example?
Change the physical properties of an ecosystem and make it inhospitable to endemic species.
The Sahara desert is expanding southward at 5-8km/year due to removal of vegetation along the southern border.
What is conservation biology/ecology?
A science with the specific goal of preserving species and ecosystems.
Classically, what is conservation biology focused on? What does modern conservation biology focused on?
Preserving endangered species.
Preserving ecosystems.
Why is it a main problem if species go extinct?
Ethical Argument: People like nature and species have a right to exist.
Practical Argument: Organisms help people in many ways (medicine, ecological services).
Many commercial medicines (drugs) are derived from…
Natural compounds.
The cancer drug “Taxol” is a compound that was identified from…
the Pacific Yew tree.
Maintaining or restoring ecosystems is…
Cost effective and can be beneficial to humans.
Keystone species
Community members that have a disproportionate influence on the community composition.
Usually animals, reduce competition by reducing the population size of a very good competitor.
Reduced competition allows for additional species to exist in the community that otherwise might be out-competed.
Single species focused efforts have ____ success. Why?
minimal
Re-introduction of sea otters have been successful only where habitat is high quality.
Mortality is high when re-introduced to poor quality habitat.
Conserve communities because more diverse communities are generally….
- Healthier
- More productive
- Better able to withstand stress
- Resist invasive species better
- Are more sustainable (reliable)
Conservation plans that… tend to work the best.
improve the local economy
