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Scientific study of the interactions that determine the distribution and abundance of organisms.
What are the 3 different scales of ecology?
Zoogeography, Niche ecology, Habitat selection
Conditions in which a species can survive and reproduce. Determined by things like water, temperature, size, diet, habitat use, behavior etc.)
A fundamental niche is the spectrum of conditions in which a species COULD survive and reproduce. A realized niche is the set of conditions actually used by a species due to interactions with other species, dispersal limitations or low recruitment.
Why would the realized niche be smaller than the fundamental niche?
Perhaps there is competition
What are 3 fundamental components of a fundamental niche?
Why is water economy so important?
It’s a basic requirement of life. The balance of gain vs loss of water can limit distribution. Thus, water efficient species can occupy areas other species don’t occur, where there is less competition and predation.
How is water lost?
What relationship is there between evaporative water loss and ambient humidity?
When humidity is high we expect water loss to be low. When its dry we expect it to be high.
How is water gained?
Drinking free water like from rivers or lakes. Preformed, like from fruit or tissues of other foods. Metabolic, which is water produced as a byproduct generally through digestion. Carbs, fats and other complex molecules can give water when broken down.
How do different animals minimize water loss when getting rid of nitrogen?
Birds have highly concentrated nitrogen waste, but it takes a lot of energy to concentrate it. Mammals use a lot of water in removing nitrogen but it’s energetically cheap. Kangaroo Rats are an exception to mammal case, as it concentrates is urine much more but reduces evaporative water loss by staying in cool burrows. It maximizes its water gain by eating oily starchy seeds.
How does body size relate to water efficiency?
Small animals have much more surface area relative to volume than large animals. Therefore they have to worry much more about evaporative water loss.
How do sea animals get their water?
Metabolically or in free form from fish with fresh water in them. All sea organisms have salt excreting sites.
What is thermoregulation?
Managing body temperature
How is body heat regulated?
We have to dissipate when hot and collect or generate when cold.
What are two types of thermoregulation?
Homeothermic: endotherms, internal heat is created through metabolism.Poikilothermic: ectotherms, rely on external heat to maintain body temperature
What is an example of a homeotherm?
Bluefin tuna which are able to generate heat by constantly moving. A countercurrent heating system enables them to hold on and maintain heat generated from constant muscle movement. Why would it be adaptive to be hotter than the water around them? It allows them to move between diff water temps easily. Muscles perform better when they’re warmer, heat efficiency helps the fish go 60mph.
What is an example of a poikilotherm?
Humming birds. Its heart beats 1200bpm. On cold mornings, it drops to 60bpm. They go into torper. They metabolically slow down their bodies. Many mammals and birds have the ability to change their energy output in response to ambient temperature. Why do they shut down their bodies, sacrificing ability to escape? Fast metabolism takes a lot of energy. When they can shut down, they shut down.
Name one physical, one chemical and one behavioral way Homeotherms manage heat:
What are the critical points in the region of homeothermy?
(range over which an animal can maintain body temp)
What are the four physical processes of heat transfer?
1. Radiation: heat loss or gain through the air.
2. Conduction: heat loss or gain through direct contact with a warmer or colder surface
3. Convection: heat loss when wind passes a body and pulls heat away.
4. Evaporation: heat loss as water vaporizes on skin.
What is Bergmann’s Rule?
Individuals of the same species will be smaller in warm climates and larger in colder climates
What is Allen’s rule?
Animals in colder climates have smaller extremities and vice versa.
What is counter-current thermoregulation?
It is a special structure for heat retention in which warm arterial blood from the heart passes adjacent to cool venous blood returning from extremities, conserving heat before blood reaches the extremities.
How do fur and feathers help manage temperature?
Fur and feathers create dead air space, reducing convective heat loss.
How does coloration manage temperature?
White allows light to pass through. In cold climates you’ll see white feathers/fur and black skin. Solar heat comes through the white, hits the black skin where it is absorbed, the white fur creates the dead air space to hold onto heat. In hot windy climates, a black layer held off the skin absorbs heat where it is then blown away via convection.
What is habitat selection?
Process by which an animal identifies a site to settle on the landscape.
How are niches, habitat selection and social organization related?
A niche determines at broad spatial and temporal scales where animals CAN exist. Habitat selection determines at finer scales where animals actually settle. Habitat selection creates spatial patterns of individuals (dispersion) which gives rise to social organization.
What are the two types of habitat selection?
Habitat specialists are restricted to a limited range of habitat types. Generalists are capable of surviving and reproducing in many habitats.
Name a few limiting habitat factors
Food is one of the most important limiting factors. Water is important in dry areas and for animals that depend on free water. Cover is important in open exposed environments. Temperature limits activity and distribution of organisms. Presence and absence of predators and competitors. Mobility limits dispersal and movement. Special needs like nesting sites, mud baths, minerals etc.
What is the numerical response of predators to increased prey?
Regulation of water levels is critical, and such is critical to habitat selection. Fish obviously must live in water. Baboons need to live near water. The topi lives a little more independently and far from water. The sand grouse with its sponge feathers can settle far from water.
How does soil affect settlement?
It is important for burro construction which is essential to rodents, some birds and reptiles. Muddy conditions can impair movement. It is important for crypsis which is key to catching prey and hiding from predators.
How to predators affect settlement?
Risk of predation can affect settlement. Animals, like colonial seabirds, may choose predator free habitats. They may choose habitats with ample escape terrain, like mountain goats. They may choose habitats with good cover. Logs or debris are important for small animals.
How do social factors may affect settlement?
How do animals ‘know’ what habitat to select?
Genetic encoding where preference is passed on through genes. Imprinting involves animals 'taking note' the habitat around them in their natal period, early development. They look for a similar habitat when its time to breed. Learning where animals preference comes through negative and positive experiences (species that live a long time).
Why do humans and elephants live well beyond their reproductive stage?
Older individuals can still contribute, have knowledge, they take care of young. In an experiment with removing older female elephants the behavior of the group was significantly changed. Younger ones were more aggressive, older ones didn’t know all the migration routes.
How is habitat selection measured?
Important habitat variables like food, water and cover are defines. These variables are measured across a landscape. Then you compare “use” to “availability.”
What is the relationship between niche, habitat selection, social organization and dispersion/mating systems?
How do males and females differ in energy spent on offspring?
Males have 400 billion sperm, no gestation cost and little investment in offspring. Meanwhile Females have only 400 ova, great gestation cost and heavy investment in offspring. Thus, Males aren’t picky about reproductive opportunities while females need to be selective
What is dispersion?
The spacing of individuals on the landscape
How does dispersion differ between genders?
What are the two components of social organization?
Why are some species most often solitary while others are group living?
What types of species are solitary?
What types of species are Pair-Living?
Similarly to solitary species except survival of young often relies on bi-parental care. Forest birds, a few mammals.
What types of species are gregarious?
Usually herbivores or frugivores with low-quality diets and hwere food is widely distributed and predation is significant, or where food appears ephemerally in clumps. Many mammals, some birds. Clumped dispersion.
Colonial characterized by pair breeding units, where many pairs come together to form a colony. Sea birds and mammals.
Communal are family groups, one breeding pair like an 'alpha pair' which reproduces , and other 'helpers' that help raise and defend young.
A few mammals & birds.
Adults provide significant care to young that are not their own genetic offspring
Helpers are ususally grown offspring that help parents rear younger siblings.
Wolves often have breeding alpha pair and other help take care of young. Relatively rare in nature. Other examples are african wild dgos, naked mole rates and the local Acorn Woodpecker.
What is intrasexual selection
Battles between mates can be costly, there is risk in fighting. Its common because its competition to pass on your genes. Nothing else is as important.
Birds with extermely long tails can get caught on things and die. Color of feathers/scales can be an indicator of health. Perhaps an adaptation to reveal quality of males
If you don’t invest much in taking care of young you can afford to have many young.
What limits growth?
RESOURCES. Food, water, shelter/nesting sites, etc.
K. The number of [intraspecific] individual organisms the resources of a given area can support.
What is environmental resistance?
The factors which act jointly to limit a population's growth
What is density dependent population growth?
Density-dependent mortality: mortality (death) rate is a function of population density (Higher density = higher mortality)
D-dependent causes of mortality: Predation, disease, starvation
Density-independent mortality: mortality is independent of
population density (random/stochastic)
D-independent causes of mortality: Catastrophes, pollution
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