Ecology Flashcards
Camouflage
some organisms resemble others so they are concealed, e.g. stick insects resemblewoody stems.
Pollination
the transfer of pollen grains from the anthers to the stigmas of flowers
Support
some organisms use others for support, e.g. birds build nests in tree
Protection
some organisms use others for protection, e.g. grasshoppers live in long grass.
Competition
members of the same species and of different species may compete with each other. Animals compete for food, space, a mate and shelter. Plants compete for light, water and minerals.
State the ultimate source of energy in a food chain or web.
Sunlight energy
During photosynthesis, primary producers absorb sunlight energy and convert it into chemical energy, which is stored in organic food molecules. Some of this energy is then released during respiration and some is passed on through the organic molecules.
Why only 10% of energy is passed down. Limited number of trophic levels
Because there is less energy and biomass at each trophic level in a food chain, fewer organisms can be supported at each level.
Due to the loss of energy and biomass at each level, food chains rarely exceed four or five trophic levels.
How energy is lost from one trophic level to another.
At each trophic level in a food chain, energy and biomass (amount of biological matter) are lost. Some organic matter containing energy is lost in FAECES and some is lost in organic EXCRETORY PRODUCTS, e.g. urea. Some is used in RESPIRATION during which the stored energy is RELEASED AND USED, or LOST AS HEAT. The remaining energy containing organic matter is used in GROWTH AND REPAIR, and is then passed on to the next trophic level when organisms are consumed. Organisms not consumed eventually die
How energy is gained from one trophic level to another
The organic matter in faeces, excretory products and dead organisms is decomposed by decomposers and they release the energy during respiration. Energy, therefore, flows from producers to consumers to decomposers in one direction through ecosystems, and is not recycled. In general, only 10% of the energy from one level is transferred to the next level.
GRIMNER
the seven life processes;
growth,
reproduction,
irritability,
movement,
nutrition,
excretion,
reproduction.
Nutrition (feeding):
the process by which living organisms obtain or make food.
Animals take in ready-made food and are called heterotrophs. Plants make their own food and are called autotrophs.
Respiration:
the process by which energy is released from food by all living cells.
Aerobic respiration requires oxygen and takes place in most cells. Anaerobic respiration takes place without oxygen in certain cells.
Excretion:
the process by which waste and harmful substances, produced by chemical reactions occuring inside body cells
i.e the body’s metabolism, are removed from the body
Movement
is a change in the position of a whole organism or of parts of an organism.
Most animals can move their whole bodies from place to place. Plants and some animals can only move parts of their bodies
Irritability (sensitivity):
the ability of organisms to detect and respond to changes in their environment or within themselves.
Growth
Growth: a permanent increase in the size and complexity of an organism
Reproduction:
the process by which living organisms generate new individuals of the same kind as themselves.
Asexual reproduction requires only one parent. Sexual reproduction requires two parents.
Types of methods to classify organisms- via DNA
useing the molecular structure of deoxyribonucleic caid (DNA) to assist in grouping organisms
The greater similarity in their DNA structure, the more closely related are the organisms.
Another type of methods to classify living organisms
by analyzing visual characteristics i.e number of legs, number of body parts, shape, arrangement of veins in a leaf or an insect wing’s.
Another type of methods to classify living organisms-
Species
The basic category of classification is the species. A species is a group of organisms of common ancestry that closely resemble each other and are normally capable of interbreeding to produce fertile offspring.
Grouping of organisms
species —-> genera —–> families —–> orders —–> classes —–> phyla —-> kingdoms
Ecology
the study of the interrelationships of living organisms with each other and with their environment
Environment
the combination of factors that surround and act upon an organism.
Biotic factors
all the other living organisms that are present such as predators, prey, competitors, parasites and pathogens
Abiotic factors:
all the non-living chemical and physical factors
Habitat
the place where a particular organism lives.
For example, the habitat of an earthworm is the upper layers of the soil
Population
all the members of a particular species living together in a particular habitat.
For example, all the sea urchins living in a sea grass bed form a population.
Community:
all the populations of different species living together in a particular habitat.
For example, a woodland community consists of all the plants, animals and decomposers that inhabit the wood.
Ecosystem:
a community of living organisms interacting with each other and with their abiotic environment
Examples of ecosystems include a pond, a coral reef, a mangrove swamp, a grassland and a forest.
Niche
the position or role of an organism within an ecosystem.
For example, an earthworm’s niche is to burrow through the soil, improving its aeration, drainage and fertility.
The aim of studying an ecosystem
The aim of studying any ecosystem is to identify the different species of plants and animals present, to find out where they live, determine their numbers, and find out about the relationships they have with each other and with the abiotic factors.
Herbivores
consume plants, e.g. cows, grasshoppers, snails, slugs, parrotfish, sea urchin
Carnivores
consume animals, e.g. lizards, toads, spiders, centipedes, eagles, octopuses, sharks.
Omnivores
consume both plants and animals, e.g. hummingbirds, crickets, humans, crayfish.