Section 1.4 Ecology (Higher Level) Population Ecology

Section 1.4 Ecology (Higher Level) H ECOLOGICAL RELATIONSHIP Factors that control populations. Definition of “competition” Examples: contest competition – an active physical confrontation between two organisms which allows one to win the resource scramble competition – each organism tries to acquire as much of the resource as possible. Relate competition to size of population. Outline one adaptive technique of an organism to survive competition. Definition of “predation”. Examine any three adaptive techniques of (a) predators and (b) prey. Give one simple example of a predator/prey relationship to illustrate population control. Definition of “parasitism” with example. Definition of “symbiosis” with example.

Section 1.4 Ecology (Higher Level) Ecological Pyramids Pyramids of numbers represent feeding stages in a food chain

Section 1.4 Ecology (Higher Level) Normal shape looks like a pyramid! Usually as you go up the pyramid: The number of individual organisms decrease The size of the individual organisms increase

Section 1.4 Ecology (Higher Level) Limitations of Pyramids of Numbers It doesn’t take account the size of each organism. A grass plant and a tree would each count as one organism, even though the oak tree can feed lots more consumers!

Section 1.4 Ecology (Higher Level) Inverted pyramid of numbers If the producer is very large the pyramid will have an inverted shape Oak Tree Greenfly Ladybird Blackbird Hawk

Section 1.4 Ecology (Higher Level) Population Ecology

What you should learn about today.. What a population is What competition is and the difference between the two types What adaptations are and examples Definitions and examples of parasitism Definitions and examples of symbiosis Section 1.4 Ecology (Higher Level)

Population ecology A population is all the members of a species living in an area. The population of Blue Whales on earth is 1,300 to 2,000

Section 1.4 Ecology (Higher Level)

Competition Def Competition is when organisms struggle for a resource that is in short supply

Section 1.4 Ecology (Higher Level) Contest competition Contest competition is when there is an active physical confrontation between two organisms which allows one to win the resource.

Section 1.4 Ecology (Higher Level) Scramble competition In scramble competition the organisms share the resource - each will try to get as much as possible for themselves. Aphids display scramble competition as they compete with each other for food

Section 1.4 Ecology (Higher Level) Organisms adapt to reduce competition. Adaption The white butterfly adapts to its environment by having special eating habits. As a caterpillar it feeds on cabbage, but as an adult butterfly it feeds on nectar. This reduces competition for food between young and old members of the population!

Section 1.4 Ecology (Higher Level) Predation Def Predation is when one organism catches and kills another organism for food. Ladybird (the predator) kills and eats the aphid (prey) Prey and predator relationships can be used to control population sizes. Ladybirds can be introduced into an area to reduce numbers of aphids

Adaptations for feeding relationships The skills of a predator are based around finding, catching and killing prey The skills of prey species are based around awareness and avoidance of predators. Herbivores need the skills to find and eat their food. Section 1.4 Ecology (Higher Level)

Adaptations of Predators 2. Cheetahs are camouflaged to help them to hide from their prey. 3. Wolves hunt in packs to catch and kill their prey 1. ladybirds have strong mouth parts to chew aphids

Section 1.4 Ecology (Higher Level) Can you spot the second cheetah?

Section 1.4 Ecology (Higher Level) 1)Camoflage -The baby harp seal's white coat makes it hard for predators to spot the young seal on the ice. 2) Some plants have thorns to discourage herbivore predators from eating them 3) The yellow dart frogs excrete poison to discourage predators from eating them Adaptations of Prey

Check your learning... What a population is What competition is and the difference between the two types What adaptations are and examples How prey are adapted to survive How predators are adapted to survive Section 1.4 Ecology (Higher Level)

Adaptations of caterpillars activity orer/ecosystems/be_an_explorer/map/for m_caterpillars.htm# Section 1.4 Ecology (Higher Level)

What you should learn about today.. Definitions and examples of parasitism Definitions and examples of symbiosis Section 1.4 Ecology (Higher Level)

Symbiosis Symbiosis occurs when two organisms live in close association and at least one of them benefits. Example: Nitrogen fixing bacteria in nodules of plants Bacteria provides nitrates for the plant Plant provides the bacteria with food and shelter

Section 1.4 Ecology (Higher Level) Parasitism Def Parasitism occurs when two organisms live in close association and one organism (the parasite) gets its food from another organism (the host) and does is harm in the process. Example: Fleas on a dog!

Which one? Section 1.4 Ecology (Higher Level) The clownfish can come in contact with the stinging tentacles of the sea anemone and not be harmed by them. At the same time, it receives protection from its enemies. The clownfish feeds the anemone by gathering nutrients and also leaving nutritional waste on the tentacles.

Which one ? Tapeworms, for example, have no gut, so that they rely on their host to provide them with already digested food.Tapeworms Section 1.4 Ecology (Higher Level)

the hermit crab and a sea anemone The anemone is often found attached to the shell in which the hermit crab lives. Often, a sea anemone attaches itself to the crab's shelter and it may envelop part of the crab's own shell as well. As the crab moves about in search of food the anemone is brought into contact with a greater supply of food and the crab is protected by the anemone's stinging cells. Section 1.4 Ecology (Higher Level)

A familiar wildlife scene in Africa is that of oxpeckers running over the backs of rhinoceroses. These birds rid their partners of injurious and annoying pests and in doing so obtain a ready supply of food Section 1.4 Ecology (Higher Level)

What did you learn about population dynamics today?

Section 1.4 Ecology (Higher Level) POPULATION DYNAMICS DEPTH OF TREATMENT 1.Students should be capable of outlining the contributory factors or variables in predator/prey relationships 2.Factors that affect human population numbers 3.Current human population figures and explanations

Section 1.4 Ecology (Higher Level) Population Dynamics About the factors that cause population numbers to change.

Section 1.4 Ecology (Higher Level) Time 2.numbers of predators increase as they more food to eat and breed. 3. Once predator numbers rise more prey are killed - the number of prey starts to fall 4. When prey numbers drop, the predators have less food and their numbers drop- they starve or migrate 5. When there are less predators around the number of prey rise again! 1.prey has food and numbers increase as they breed Predator and prey relationships

Section 1.4 Ecology (Higher Level) Factors that contribute to prey and predator relationships Food If numbers of prey drop predators have ______ food and numbers __________ If numbers of predators decrease the numbers of prey will ____________ Concealment If prey can hide from predators they can prevent getting killed and numbers __________________ Migration If predators leave an area, the numbers of prey_____________________

Section 1.4 Ecology (Higher Level) Factors that effect the human population How will each of the following effect human population numbers? 1.war 2.famine 3.contraception 4.disease.

Section 1.4 Ecology (Higher Level) 1. War Reduces population due to death. Currently 800 people in the world die every day due to war

Section 1.4 Ecology (Higher Level) 2. Famine An extreme and ongoing lack of food causes a famine. Causes population numbers to decrease.

Section 1.4 Ecology (Higher Level) 3. Contraception Any human intervention that stops births. Reduces population numbers. The increased availability of contraceptives has reduced birth rates since the 1960s.

Section 1.4 Ecology (Higher Level) 4. Disease Bacterial and viral diseases can kill people and cause a lack of food or clean water. Despite the availability of medicines for many diseases many people still can’t afford them

Section 1.4 Ecology (Higher Level) Human Population The human population is about 6 billion and still growing!

Section 1.4 Ecology (Higher Level) Why is the population growing so fast? Improved public health water supplies and waste removal Improved agriculture domesticated plants and animals- more food ! Better medical care – vaccinations and antibiotics readily available for lots of people.

Section 1.4 Ecology (Higher Level) Did you learn… 1.Students should be capable of outlining the contributory factors or variables in predator/prey relationships 2.Factors that affect human population numbers 3.Current human population figures and explanations