TOPIC 7 - ECOLOGY Flashcards
define habitat
the place where an organism lives
define population
all the organisms of one species living in a habitat
define community
the populations of different species living in a habitat
what are abiotic factors?
non-living factors of the environment eg temperature
what are biotic factors?
living factors of the environment eg food
define ecosystem
the interaction of a community of living organisms (biotic) with non-living (abiotic) parts of their environment.
what do plants compete for?
light, space, water and mineral ions (nutrients) from the soil.
what do animals compete for?
space(territory), food, water and mates.
what is interdependence?
each species depends on other species for things such as food, shelter, pollination and seed dispersal.
The interdependence of all the living things in an ecosystem means that any major change in the eco system can have far-reaching effects.
give examples of abiotic factors
non-living factors such as: moisture level light intensity temperature carbon dioxide level (for plants) wind intensity and direction oxygen level (for aquatic animals) soil pH and mineral content.
give examples of biotic factors
living factors such as: new predators arriving competition - one species might outcompete another so that the numbers are too low to breed. new pathogens availability of food.
what re adaptions?
the features or characteristics that allow organisms to live in different environmental conditions are called adaptions.
what can adaptions be?
structural
behavioural
functional
what are structural adaptions?
these are features in an organism’s body structure - such as shape or colour.
eg animals that live in cold places, like whales, have a thick layer of blubber (fat) and a low surface area to volume ratio to help them retain heat.
what are behavioural adaptions?
these are ways that organisms behave. Many species, eg swallows, migrate to warmer climates during the winter to avoid problems of living in cold conditions.
what are functional adaptions?
these are things that go on inside an organism’s body that can be related to processes like reproduction and metabolism.
Eg desert animals conserve water by producing very little sweat and small amounts of concentrated urine.
brown bears hibernate in winter. They lower their metabolism which conserves energy, so they do not have to hunt when there is not much food around.
What are extremophiles?
Some microorganisms (eg bacteria) are adapted to live in very extreme conditions. For example, some can live at high temperatures and others can live in places with a high salt concentration or at high pressure, eg deep sea vents.
what are producers?
producers make their own food using energy from the sun. Eg green plants or algae - they make glucose by photosynthesis. When a green plant produces glucose, some of it is used to make other biological molecules in the plant. These biological molecules are the plants biomass - the mass of a living material.
what is biomass?
Can be thought of as energy stored in a plant.
what order does the food chain go?
producers
primary consumers
secondary consumers
tertiary consumers.
how would a change in the availability of water affect the distribution of organisms?
The distribution of some animals and plant species in the tropics changes between the wet and dry season. Ie in the times of year where there is more or less rainfall, and so more or less water available. eg each year in Africa, large numbers of giant wildebeest migrate, moving north and then back south as the rainfall pattern changes.
how does a change in temperature affect the distribution of organisms?
The distribution of bird species in Germany is changing because of a rise of average temperatures. E.g. the European bee-eater bird is a Mediterranean species but it is now present in parts of Germany.
how does a change in the composition of atmospheric gases affect the distribution of organisms?
The distribution of some species changes on areas where there is more air pollution. E.g. some species of lichen can’t grow in areas where sulfur dioxide is given out by certain industrial processes.
what can environmental changes be caused by?
seasonal factors
geographic factors
human interactions
what is the water cycle?
energy from the sun makes water evaporate from the land and sea, turning it into water vapour. Water also evaporates from plants - this is known as transpiration.
The warm water vapour is carried upwards because warm air rises. When it gets higher up it cools and condenses to form clouds.
water falls from the clouds as precipitations onto land, where it provides fresh water for plants and animals.
It then drains into the sea, before the whole process starts again.
how are elements cycled back to the start of the food chain by decay?
living things are made of materials they take from the world around them. E.g. plants turn elements like carbon, oxygen, hydrogen and nitrogen from the soil and the air into complex compounds (carbohydrates, proteins and fats) that make up living organisms. These get passed up the food chain.
These materials are returned to the environment in waste products, or when organisms die and decay.
Materials decay because they are broken down (digested) by microorganisms.
Decay puts stuff that plants need to grow back into the soil eg mineral ions.
In a stable community, the materials that are taken out of the soil are used by plants are balanced by those put back in. There is a constant cycle happening.
when does decay happen quickest?
warm, moist and aerobic conditions.
what happens during the carbon cycle?
co2 is removed from the atmosphere by green plants and algae during photosynthesis. this carbon is used to make glucose, which can be turned into carbohydrates, proteins and fats that make up the bodies of the plants and algae.
When the plants and algae respire, some carbon is returned to the atmospere as co2.
when they are eaten, the carbon moves through thr food chain.
when the animals respire, the carbon is returned to the atmosphere as co2.
when plants, algae and animals die, other animals (called DETRITUS FEEDERS) and microorganisms feed on their remains. When these organisms respire, c02 is returned to the atmosphere.
animals also produce waste that is broken down by detritus feeders and microorganisms.
so the carbon (and energy) is constantly being cycled.
what is compost?
decomposed organic matter that is used as a natural fertiliser.
what microorganisms are responsible for decay?
bacteria
fungi
detritus feeders
how does temperature affect the rate of decay?
warmer temperatures make things decompose quicker because they increase the rate that enzymes involved in decomposition work at. if it gets too hot, the rate slows down or stops because the enzymes are destroyed and the organisms die.
