Chapter: Interactions of Life Table of Contents Section 3: Interactions Within...

Chapter: Interactions of Life

Table of ContentsTable of Contents

Section 3: Interactions Within Communities

Section 1: Living Earth

Section 2: Populations

• Biosphere - part of Earth that supports life is The Biosphere11

Living EarthLiving Earth

• Different environments = different organisms

The Biosphere11Living EarthLiving Earth

• Earth - just right for life.

• Mercury - too hot during the day and too cold at night

Life on Earth 11

Living EarthLiving Earth

• Venus – too hot

• Mars - colder than Earth

• farther from Sun

• thinner atmosphere.

• Ecosystem - all the living and nonliving parts of an environment

Ecosystems 11Living EarthLiving Earth

11Living EarthLiving Earth

• Ecology - study of interactions between organisms and their environments.

• Ecologists - scientists who study Ecology

Ecosystems

• Population - all organisms of the same species that live in an area at the same time.

Populations11Living EarthLiving Earth

• Community - all the populations of species living in an ecosystem.


Populations


• Habitat - place where an organism lives

• Provides:

• Food

• Shelter

• Temperature

• Moisture

Question 111

Section CheckSection Check

Earth’s _____ includes the top part of Earth’s crust, all the waters covering Earth’s surface, and the atmosphere surrounding Earth.

A. biosphere B. carrying capacity C. ecosystemD. limiting factor

11

The correct answer is A. The biosphere is defined as the part of Earth that supports life and living things.

Answer


11

This illustration can be used to represent a forest community because it _______.

Question 2


11

A. shows birds gathering twigs to make nests.B. shows clouds representing rainfall.C. shows deer grazing on grass.D. shows many different populations living together.


11

The correct answer is D. A community includes the populations of all species that live in a particular ecosystem. The illustration shows populations of deer, blue birds, and various species of plants.

Answer


11

What kind of scientist would study how bison grazing on prairie grass affect the grasshoppers that lived in the prairie?

Ecologists study interactions that occur among organisms and their environment.

Question 3

Answer


22PopulationsPopulations

• Competition occurs when two or more organisms seek the same resource at the same time.

Food, Water, and Space

• Competition limits population size


Growth Limits

• Can occur between the same species or different species

• Population density - number of individuals of one species per a specific area.


Population Size

Measuring Populations 22PopulationsPopulations

• 1 method - trap-mark-release.

• Use sample counts to estimate the sizes of large populations

Sample Counts 22

PopulationsPopulations


• Limiting factor - anything that restricts the number of individuals in a population.

• Carrying capacity - largest number of individuals of one species that an ecosystem can support over time


Click image to view movie.

• Biotic potential - highest rate of reproduction under ideal conditions


• Birth Increases population22PopulationsPopulations

• Death Decreases population


• Immigration Increases population

• Emmigration Decreases population

• Exponential growth - the larger a population gets, the faster it grows.



• Carrying capacity influenced by infectious diseases

Question 1 22


How might competition with the owl and woodpecker limit the growth of the population of the lizards shown in this illustration?

22

A. there would be more competition for food B. there would be more competition for nesting spaces C. there would be more competition for sunlightD. there would be more competition for water


22

The correct answer is B. All three animals use the cactus for nesting spaces. If nesting spaces are limited, the lizards may not be able to raise young and their population size will be limited.

Answer


Question 2 22

An ecologist measured 10 square meters of beach and counted 50 crabs. The scientist then multiplied 50 by 10 and estimated that there were 500 crabs on 100 square meters of beach. What tool was the ecologist using?

A. biotic count B. capacity count

C. limiting countD. sample count


22

The correct answer is D. Sample counts are used to estimate the sizes of large populations.

Answer


Question 3 22

Which has the highest biotic potential, a fish that can produce 4000 eggs a year or one that can produce 20 eggs a year?

The fish that can produce 4000 eggs a year has the highest biotic potential. Biotic potential is the highest rate of reproduction under ideal conditions.

Answer


Organisms Need Energy33Interactions Within CommunitiesInteractions Within Communities

• Sun - source of energy for most life on earth

• Producers - Organisms that use an outside energy source to make energy-rich molecules

33Interactions Within CommunitiesInteractions Within Communities

• Most contain chlorophyll

• Consumers - organisms that cannot make their own energy-rich molecules


• Obtain energy by eating other organisms

• Herbivores – eat plants


Consumers

• Omnivores - eat plants and animals.


• Carnivores - eat other animals


• Decomposers - consume wastes and dead organisms.

• Food chain - model of the feeding relationships in an ecosystem



• Symbiosis - close relationship between species


• Mutualism - symbiotic relationship in which both species benefit

• Commensalism – 1 organism benefits and the other is not affected


• Roundworms, are common in puppies.

Parasitism 33Interactions Within CommunitiesInteractions Within Communities

• The roundworm attaches itself to the inside of the puppy’s intestine and feeds on nutrients in the puppy’s blood.


• Parasitism - 1 organism benefits but the other is harmed


• Niche – organism’s role in its environment


• Predator - consumers that capture and eat other consumers

• Prey - the organism that is captured by the predator

Question 133


Fleas often live on dogs or cats and bite them for a meal of blood. This can be harmful to the cat or dog that is bitten. What type of symbiotic relationship is this?

This is an example of parasitism. In this type of relationship, one organism is harmed, while the other benefits.

Answer

Question 233

How do producers that contain chlorophyll make energy rich molecules?

A. they use chemosynthesis B. they use commensalismC. they use mutualismD. they use photosynthesis


Answer33

The correct answer is D. Green plants contain chlorophyll so that they can use the energy of the Sun for photosynthesis.


Question 333

Which describes how predators affect an ecosystem?

A. decrease the number of niches in the ecosystem B. decrease the number of species in the ecosystemC. increase competition among speciesD. limit the size of the prey population


Answer33

The correct answer is D. Because predators limit the prey populations, food and other resources are less likely to become scarce and competition between species is reduced.


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