Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Biodiversity action plan wikipedia , lookup
Storage effect wikipedia , lookup
The Population Bomb wikipedia , lookup
World population wikipedia , lookup
Two-child policy wikipedia , lookup
Source–sink dynamics wikipedia , lookup
Molecular ecology wikipedia , lookup
EST 4 THE LIVING WORLD CHAPTER 9 Populations and Communities (pp. 291 –309) 1 Studying Populations A population is a group of individuals of the same _________________, living in a _____________ space at a specific _______________ in time. Examples: Green frogs in a marsh Balsam fir on a mountainside __________________________________________ Why do ecologists study populations? ______________________________________________________________________________ ______________________________________________________________________________ Three main characteristics that describe a population: 1. ___________________________ 2. ___________________________ 3. ___________________________ 1.1 POPULATION SIZE Population size refers to the __________________ of individuals in a _____________________. Why is it useful to know the size of a population? ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ Over time, the size of a population may ____________________, ____________________ or remain _____________________. 1 EST 4 THE LIVING WORLD FOUR FACTORS AFFECTING POPULATION SIZE Factor Description Births of individuals within a population Births Deaths of individuals within a population Deaths Immigration Arrival among the population of individuals from other regions Emigration Departure of individuals to other regions What two factors increase population size? Births & Immigration What two factors decrease population size? Deaths & Emigration If the births and immigration rates are greater than the death and emigration rates, then the population ______________________. If the births and immigration rates are less than the death and emigration rates, then the population ______________________. If the births and immigration rates are equal to the death and emigration rates, then the population ______________________. METHODS OF MEASURING THE SIZE OF A POPULATION 1. Counting individuals 2. Counting by sample area This method consists of counting the individuals in _____________________ selected _________________ of the study area and estimating the total population size with the following equation: __________________________________________________ = ___________________________ What are quadrats? _____________________________________________________________ 2 EST 4 THE LIVING WORLD For what types of populations are quadrats a useful counting technique? ______________________________________________________________________________ 3. Mark and recapture This method is commonly used to count populations of very __________________ animals, such as, ____________________, _____________________, ___________________ and _____________________. It consists of the following stages: Installing ___________________ or nets in the populated region Counting the ____________________ animals and __________________ them with ________________, _________________, __________________ or ___________________ _______________________ the marked animals Reinstalling __________________ or _________________ Counting the captured individuals again, with a separate count for ___________________ individuals ________________________ the size of the population using the following calculation: ________________________________________________ = _________________________________ 1.2 POPULATION DENSITY Population density refers to the number of individuals per unit of ______________ or ___________________. __________________________________ = _________________________________________ 3 EST 4 THE LIVING WORLD Some factors affecting population density Good supply of food and water __________________________ Presence of _____________________, _______________________ or __________________ Natural or human-caused _____________________ 1.3 POPULATION DISTRIBUTION Population distribution is the way in which individuals are ____________________ within their ____________________. There are three main patterns of population distribution 1. ____________________ distribution Example: Many ______________ move around in _________________. 2. _____________________ distribution Example: Northern ________________ space their nests at regular ____________________. 3. ______________________ distribution Example: _________________ in a field 4 EST 4 THE LIVING WORLD 1.4 ECOLOGICAL FACTORS An ecological factor is an aspect of a habitat that can affect the ____________________ living there and thus the population ____________________. There are two types of ecological factors: 1. ___________________ (non-living) factors: These are __________________ or _________________ aspects of the environment. 2. ____________________ (living) factors: These are related to the ______________ of living organisms in a habitat. EXAMPLES OF ABIOTIC FACTORS Abiotic Factors Biotic Factors Disease Terrain Competition Air Humidity A ____________________ FACTOR is an ecological factor that causes the density of a population to decrease. Examples: Exposure to _________________ ____________________ is a limiting factor in the growth of rose bushes. Amount of _________________ in the ground is a limiting factor in the growth of cacti. The size of the _____________ _____________________ is a limiting factor for the snake population. 5 EST 4 THE LIVING WORLD 1.5 BIOLOGICAL CYCLES IN POPULATIONS The biological cycle of a population consists of the alternating periods of ______________ and ______________ in its size. These periods are of ______________ duration and are __________________ continually. The most commonly studied biological cycles in Quebec are those of the lynx and the snowshoe hare. (See figure 9.14 on p. 302) When the hare population rises, the lynx have _____________ food, so they become healthier and __________________ more causing their population to ______________________. When the number of lynx increases, they hunt _____________ hares causing the hare population to ________________________. With fewer hares to hunt, the lynx population will eventually ____________________ as well. Finally, as the lynx population decreases, fewer hares will be hunted, so the hare population will _____________________ again and the whole cycle ________________. 2 Studying Communities A community is a set of __________________________ of different ________________ sharing the same ______________________. The squirrels, fungi, trees and mosquitoes in the forest are thus part of the same _________________________. 2.1 BIODIVERSITY Biodiversity describes the variety of ___________________ living in a ______________________. There are two components to consider when measuring the biodiversity of a community: 1. _____________________ __________________________: the number of species in the community. 2. The relative _______________________ of each species. 6 EST 4 THE LIVING WORLD The biodiversity of a community is high when two conditions are met: 1. The number of species is ___________________. 2. The relative abundance of different species is _______________________. What is the IUCN? ________________________________________________________________________ Of the 41415 species identifies in the 2007 IUCN survey, how many are threatened with extinction? _________________________ How are species protected from extinction? ________________________________________________________________________ 2.2 INTERACTION BETWEEN INDIVIDUALS IN A COMMUNITY There are four main types of interaction that may occur between individuals of a community: 1. ____________________________ 2. ____________________________ 3. ____________________________ 4. ____________________________ COMPETITION Competition is the interaction between living organisms that seek access to the _________________ ________________________ in their habitat. There are two types: _____________________________ competition: occurs between individuals of the same species. _____________________________ competition: occurs between individuals of different species. 7 EST 4 THE LIVING WORLD PREDATION Predation is the interaction between living organisms in which one _______________ on the other. The individual that feeds on another living organism is called the ___________________. The individual being eaten is called the _________________. Parasitism is a form of ______________________. The parasite feeds of the ____________ and in turn, the ________________ is ____________________ in some way. (Examples include: _______________________, _______________________, & ________________________) MUTUALISM Mutualism is the interaction between two living organisms that ___________________ both organisms. (Example: ______________________ and __________________________) COMMENSALISM Commensalism is the interaction between two living organisms in which one organism ____________________ while the other remains _________________________. Example: A warblers nest in a ______________ tree. THE EFFECTS OF INTERACTION BETWEEN POPULATIONS ON THEIR DENSITIES Type of Interaction Competition Effect on population A Effect on population B Predation and Parasitism Mutualism Commensalism END OF CHAPTER 9 8