ESS_Populations

ecology

the study of the relationships between living organisms and their physical environment

species

a group of organisms sharing common characteristics that interbreed and produce fertile offspring

population

a group of organisms of the same species living in the same area at the same time, and which are capable of interbreeding

habitat

the environment in which a species normally lives

abiotic factors

the non-living, physical factors that influence the organisms in an ecosystem

biotic factors

the interactions between the organisms in an ecosystem

niche

the particular set of abiotic and biotic conditions and resources to which an organism or population responds. an organism’s role in an ecosystem

fundamental niche

the full range of conditions and resources in which a species could survive and reproduce

realized niche

the actual conditions in which a species exists due to biotic conditions

carrying capacity

the maximum number of individuals of a species that can be sustained by an environment (where limiting factors prevent population growth)

limiting factors

they prevent population growth. example: abundance of food, competition for food.

example of limiting factors

lake winnebago, wisconsin. lake fly larva are a sustainable food source for sturgeon

mass extinction

a period in which at least 75% of the total number of species on earth are wiped out

speciation

the formation of new species when populations become isolated and evolved differently

geographic isolation

occurs when a physical barrier causes populations to become separated

keystone species

a species that is vital for continuing function of the ecosystem. without them, the ecosystem may collapse

example of keystone species

wolves in yellowstone park. they change the behavior of deers and promote forest growth which stabilizes soil, changes rivers, provides more nesting space for birds, and spaces for beavers to build dams. they help the ecosystem flourish and help biodiversity increase

flagship species

charismatic species selected to appeal to the public, and thereby help to protect other species in the area

example of flagship species

orangutans in sumatra indonesia. they are fluffy, human-like, and merchandise can be made. planeco is an ngo that campaigns to save rainforests because palm oil plantations lead to habitat loss for orangutans

interspecific competition

the competition for limited resources between individuals of different species

example of interspecific competition

sarcastic fringehead vs octopus on the california coast

intraspecific competition

when individuals of the same species compete for a limited resource

example of intraspecific competition

sarcastic fringehead vs sarcastic fingehead competing for territory on the california coast

predation

when one animal preys on another

example of predation

snowy owls prey on lemmings

parasitism

a relationship in which one species benefits at the expense of the other (parasite vs host)

example of parasitism

tapeworms attach onto the intestines of cows and eat their partly digested food, depriving it of nutrients

mutualism/symbiosis

a relationship in which both species benefit

example of mutualism

oxpeckers land on rhinos and eat parasites that live on their skin. oxpeckers get food and the rhino gets pest control

example of a species-based conservation project

indonesian sumatran tigers at the australia zoo. breeding program, insurance population. save from poaching and human conflict. fundraising

an example of a habitat-based conservation project

tarangire national park in tanzania. wildlife corridors. lions, zebras, giraffes, ostriches. no fence. local community encroachment.

an example of an igo involved in conserving or restoring biodiversity

un environment program (unep). power and international but slow to reach decisions

an example of an ngo involved in conserving biodiversity

animals asia. media and publicity but no direct power

predator-prey cycles

they regulate ecosystem populations. negative feedback loop- regulates and stabilizes

example of predator-prey cycles

snowy owls and lemmings

s shaped population curve

limiting factors begin to restrict growth and the population reaches carrying capacity. there is an increase in competition for resources

j shaped population curve

growth is initially slow and grows exponentially. it does not slow down because there are no limiting factors. the lag phase may occur as organisms seek new ways to exploit new resources

natural selection

individuals in a species show variation in their characteristics. some variation is due to genetic differences and can be passed to offspring. individuals that survive pass their genes onto their offspring. individuals with the more advantageous characteristics are more likely to survive. over generations, the frequency of advantageous characteristics will increase in the population and the species will evolve.

role of isolation in natural selection

natural selection leads to survival of the fittest where species need to adapt to new environmental conditions. isolation occurs when members of a population are prevented from interbreeding due to barriers. the isolated groups may be subject to different selective pressures so then the separate groups evolve increasingly different characteristics and become unable to reproduce fertile offspring between them.

how plate activity has influenced evolution and biodiversity

plate activity promotes isolation and speciation, where new habitats are created. by subjecting members of a population to different selective pressures, the separate groups evolve increasingly different characteristics and become unable to reproduce fertile offspring between them. this creates a new species.

causes of historic mass extinctions

meteors, volcanic eruptions, climate change, sea level changes, drop in oxygen levels

habitat-based conservation

in order to protect species diversity, their habitats also need to be protected. strategies include core areas (the pristine natural environment under protection), buffer zones (found between core and transition zone), and the transition zone (where there is a sustainable use of natural resources; area can be affected by human activities outside the transition zone)

species-based conservation

environmentalists have used large species to raise public awareness about the threats to biodiversity and the environment. in-situ conservation- protection of species in their habitat. ex-situ conservation- improve probability of survival of the species by taking them out of their habitat and breeding them in captivity

criteria used to manage and design protected areas

key features include reducing edge effect, selecting a single large reserve, close proximity of reserves to each other, connections between reserves, and proximity of reserves to potential human influences. the optimum shape is a circle because of its minimum edge to area ratio.

convention on international trade in endangered species (cites)

ratified by more than 180 nations, aims to ensure that international trade doesn’t threaten threaten the survival of species. it has three lists, appendix 1 contains species threatened with extinction and trade is allowed in special circumstances, appendix 2 contains species at risk from international trade and a permit is required, appendix 3 contains species protected in one or more countries and trade is regulated with permits and national laws.

holocene extinction

many biologists think we are now in the sixth mass extinction that started 10,000 years ago when large mammals such as the woolly mammoth and sabre-tooth tiger became extinct. the extinction rate has accelerated in the last 100 years, mostly due to climate change, caused by humans

holocene extinction vs historic mass extinctions

the rate of change is faster and it is happening over a shorter period of time. it is caused by another species changing the environment not caused by natural phenomena. humans can prevent it.