4- Ecology Flashcards
Define ecology
The study of how organisms relate to one another and to their environments
What are key elements of the environment (environmental factors)?
-Temperature
-Water
-Sunlight
-Soil
Define homeostasis
Individuals must maintain a steady-state internal environment regardless of external environment
What are conformers?
Certain animals and plants are known as conformers because they conform to the environment in which they find themselves, their bodies adopting the temperature, salinity, and other physical aspects of their surroundings
What are the 3 ways in which an organism can respond to environmental change?
1) Physiological responses
2) Morphological adaption
3) Behavioural responses
What is an example of a physiological response?
-Certain species of frog will produce antifreeze, high concentration of glucose, to prevent the formation of ice crystals which would damage their cells
-This will prevent the frog’s vital organs from freezing
-A partially frozen frog will stop breathing, and its heart will stop beating
What are ectotherms?
Animals such as reptiles, fish or amphibians, whose body temperature is regulated by their behaviour or by their surroundings
What are endotherms?
Animals that can generate their own heat, have adaptions that miniseries energy expenditure
Ex: thick fur coats during the winter
True or false? Most organisms are adapted to live within a relatively narrow range of temperatures
True
What is a behaviour response?
-Many animals deal with variation in the environment by moving from one patch of habitat to another, avoiding areas that are unsuitable.
What is an example of morphological adaption in regards to water?
Camels can withstand long periods of time without any external source of water
What is an example of behavioural response in regards to water?
The beetle collects water by holding its abdomen up on a dune crest to gather condense water
Almost all ecosystems rely on energy captured by ___________. The availabilty of ________ influences the amount of life an ecosystem can support
1) photosynthesis
2) sunlight
Exception: in underwater thermal vent where life thrives on Earth’s thermal energy and dissolved elements instead of the sun
How do deciduous trees deal with the short amount of sunlight in winter?
They shed their leaves in the fall
What is soil’s impact on the environment?
The physical consistency, pH and mineral composition of the soil often severely limits terrestrial plant growth, particularly the availability of nitrogen and phosphorus.
Ex: High temperature, salts and pH limits the growth of life in Yellowstone Geyser. Only extremophiles can live in those conditions
What does natural selection lead to?
Evolutionary adaption to environmental conditions
What is Allen’s rule of reduced surface area?
Mammals from colder climates have shorter ears and limbs to limit heat loss.
What is an example of natural selection depending on populations of the same species that live in different environments?
Most Tibetan highlanders have two mutations in a gene related to oxygen uptake, but few individuals in nearly lowland populations have these mutations
(These results suggest that natural selection has driven these mutations to high frequency in very little time, it’s not been a few thousand years since the Tibetans colonized the Himalayas)
Define population
Groups of individuals of the same species that live together in the same space and time
What are 3 characteristics of population ecology?
1) Population range
2) Population spacing
3) Metapopulation
What is population range?
Area in which a population occurs
Give an example of population range
-Polar bears are well adapted for the Arctic but you won’t find them in the tropics
-The Devil’s hole pupfish have a very narrow distribution range (they only live in one water-filled cavern in the US state of Nevada)
Can population ranges chance through time?
Yes
What is population range expansion and contraction?
Population ranges can change through time
What are examples of environmental changes?
-Shifts in attitudinal distributions of trees in the mountains of southwestern North America
-During the glacial period conditions were cooler than they are now
-As the climate warmed, trees that needed colder temperatures shifted their range upward in altitude so that they continue to vie in the colder climatic conditions
What is an example of colonization of new territory?
The cattle egret expanded is range across an ocean, from Africa to South America, probably on strong winds.
The egret continues to expand its range northward in America
What is an example of human effect on the colonization of new territory?
By altering the environment, humans have allowed some species to expand their ranges.
Coyotes began expanding their range in 1900s.This was likely aided by an expansion of human agriculture, forest fragmentation, and hybridization with other species (wolf and dog)
What are dispersal mechanisms?
-seeds can be dispersed by the wind
-seeds can adhere to the fur of animals
-seeds in fleshy fruit can be eaten and pooped elsewhere
What are population spacing patterns?
Individuals in populations exhibit different spacing patterns
What are the 3 types of spacing patterns?
1) Clumped spacing
2) Uniform spacing
3) Random spacing
What is clumped spacing and what is an advantage of it?
-Social interactions can lead to clumped distributions
-Many species live and move around in large groups
-May also represent uneven distribution of resources, like food, which i common in nature
Advantage: increases awareness and defence against predators. Decreases energy cost of moving through air and water
What is uniform spacing?
-Uniform spacing within a population may often, but does not always, result from competition for resources. (Example of trees competing for light in a forest)
-In animals, uniform spacing often results from behavioural interactions (ex: Royal Penguin competing for space to incubate their egg)
What is random spacing?
-Individuals within populations do not interact strongly with one another
-rare, can be difficult to determine between random or largely clumpy
What is metapopulation?
-comprises distinct populations that may exchange members
-usually occur in areas in which suitable habitat is patchily distributed and is separated by intervening stretches or unsuitable habitat.
What is source-sink metapopulations?
Areas in which some habitats are suitable for long-term population maintenance, but others are not.
What is dispersal (source-sink metapopulations)?
-Populations centre (source) send dispersers to surrounding areas (sink).
-Small populations send fewer dispersers and receive more migrant
-Individual populations may become extinct (disease,environmental disaster, loss of genetic variation)
What is metapopulations impact on range?
-continuous colonization of empty patches prevents long-term extinction.
-in source-sink metapopulations, the species occupies a larger area than it otherwise might.
Metapopulation example sing Glanville fritillary butterfly
-200 populations became extinct, but 114 empty meadows were colonized.
-local population’s extinction is due to small population size, low resource availability (flowers), and lack of genetic variation within the population
-None of the populations is large enough to survive for long on its own, thus this butterfly needed the continued existence of a metapopulation network, which new populations are continually created and existing populations are supplemented by immigrans
What is demography?
The quantitative study of populations, it examines how a population changes size over time.
What are factors that change a population size?
1) Birth rate (b): the number of live births per time
2) Death rate (d): the number of deaths per time
3) Immigration (i): the number moving in the population per time
4) Emigration (e): the number leaving the population per time
What is the rate of population increase formula?
R= (birth rate - death rate) + (immigration - emigration)
Population growth can be influenced by the population’s ___ ratio
Sex
Number of births are directly related to the number of _______
Females
The number of _____ usually don’t affect the birth rate since _____ can mate with several ______.
1) males
2) males
3) females
Note: exception for monogamous species, where the number of males is important
What is generation times?
The average interval between birth of an individual and birth of its offspring
Population with _____ generations can increase in size more quickly than populations with ______ generations
1) short
2) long
Generation times is positively correlated to ____ _____
Body size
Does small size always mean short generation time?
No.
For example, Newts are smaller than mice but have considerably longer generation times
What is age structure?
Determined by the numbers of individuals in different age groups
What is cohort?
A group of individuals of the same age (born in the same period)
Each cohort has:
1) Fecundity rate
2) Mortality rate
What is fecundity rate?
Defines as the number of offspring produced according to time
Because different cohorts have different fecundity and death rates, ___ ________ has a critical influence on a population’s growth
Age structure
Population with a large proportion of ____ tend to grow rapidly because an increasing proportion of their individuals are at_______ age
1) young
2) reproductive
Populations with a large proportion of _____ individuals tend to decrease, since only a small fraction of individuals are at _______ age
1) older
2) reproductive
Birth rates declined during the 1960s but when baby boomers became parents, they generated a _____
Baby boom echo
What are life tables?
They tabulate the fate of a cohort from birth until death, showing the number of offspring produced and the number of individuals that die in each time period