Interactions of Life Forms & Ecosystem Dynamics

Interactions of Life Forms & Ecosystem Dynamics

By Laura Rodriguez

The variety of traits in an organism are the result of the expression of various combinations of alleles​

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Inheritance

Meiosis has a role in genetic variation between generations

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Meiosis creates gametes & increases genetic variation​

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Meiosis

​Exchange of genes between non-homologous chromosomes

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Increases genetic variation​

Crossing Over

​​During Metaphase I, homologous pairs line up on the equator

Their orientation is random​

Creates ​many different gamete combinations, increasing genetic variation of the gametes

Independent Assortment

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Multiple Choice

Which process and type of resulting cells are represented?

• mitosis, gametes
• mitosis, body cells
• meiosis, gametes
• meiosis, body cells

Multiple Choice

• INCREASES GENETIC VARIATION

• TAKES PLACE IN PROPHASE I

• CROSSING OVER

• ALL ARE TRUE

Multiple Choice

The chromosomes that pair up during meiosis, are called __________ chromosomes.  

• homozygous 
• asexual
• homologous
• genes

Multiple Choice

What is one of the advantages, why is it better to reproduce sexually versus asexually?

• survival of the fittest
• overproduction
• genetic variation
• cloning

Multiple Choice

Genetic females have ____ and genetic males have _____ chromosomes.

• XX, XY
• XY, XX
• XX, XX
• XY, XY

Mendel discovered the principles of inheritance with experiments in which large numbers of pea plants were crossed​

​Mendel & Inheritance

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Many different ways that traits can be inherited

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Punnett square can be use to predict inheritance of traits​

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Predicting Inheritance

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​In mice, black fur color is dominant to white fur color. Predict the genotype and phenotype ratio of a cross between a heterozygous black mouse and a white mouse.

​Monohybrid Traits

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​In chickens, feather color is a co-dominant trait. Feathers can either be black, white, or black & white speckled. Predict the genotypes and phenotypes of a cross between a chicken with black feathers and a chicken with white feathers

​Co-dominant traits

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In flowers, red is incompletely dominant to white. The heterozygous phenotype is pink. Predict the genotypes and phenotypes of a cross between a pink flower and a white flower.​

​Incomplete Dominance traits

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In humans, the allele for normal blood clo​tting is dominant to the allele for hemophilia. A woman heterozygous for the trait marries a man with hemophilia. What is the probability of the couple having a daughter with hemophilia?

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​Sex-linked traits

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A man who is heterozygous for blood type A and a woman ​homozygous for blood type B have a child. What is the probability that the child will have blood type A?

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Multiple Alleles​

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Multiple Choice

When the two alleles of a particular gene are different:

• heterozygous

• homozygous

• genotype

• phenotype

Multiple Choice

The set of alleles that an individual has:

• heterozygous

• phenotype

• homozygous

• genotype

Multiple Choice

The allele that is fully expressed by itself:

• recessive

• homozygous

• dominant

• heterozygous

Multiple Choice

The allele that is not expressed when the dominant corresponding allele is present:

• dominant

• heterozygous

• recessive

• homozygous

Multiple Choice

A version of a gene:

• allele

• trait

• character

• generation

Multiple Choice

When the two alleles of a particular gene are the same:

• homozygous

• genotype

• heterozygous

• phenotype

Multiple Choice

A detectable trait or traits that result from the genotype such as color, shape, etc:

• genotype

• homozygous

• heterozygous

• phenotype

Multiple Choice

On this pedigree, the allele for curly hair is dominant. The couple labeled 2 both have curly hair, but have a daughter who does not have curly hair. Therefore, we can tell from the chart that for the couple labeled 2 -

• the male is heterozygous and the female is heterozygous.

• the male is homozygous recessive and the female is homozygous dominant.

Multiple Choice

If this pedigree shows a recessive disorder, what MUST the genotype of individual 4 be?

• HH

• Hh

• hh

The diversity of life ​has evolved and continues to evolve through natural selection

​Evolution

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• ​Alleles code for traits in organisms

• Natural selection increases the frequency of those alleles that make an individual more fit for an environment

• Natural selection ​can only occur if there is genetic variation in a population

• ​Mutations, meiosis & sexual reproduction increase variation

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​Natural Selection

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Selection pressures are external agents which affect an organism’s ability to survive in a given environment​

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Types of selection pressure:

• ​Resource availability

• Environmental conditions

• ​Biological factors

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​*** THESE ARE ALSO LIMITING FACTORS FOR POPULATIONS!!

Selection Pressures

Patterns of Evolution

• Divergent Evolution - ​species share a common ancestor - diverged into separate species because of some type of isolation

• Convergent Evolution - species do not share a common ancestor, but have similar adaptations because of similar environments

• Co-evolution - the evolution of the species influence each other​

• Gradualism - small changes​ over long periods of time

• Punctuated Equilibrium - ​periods of no change followed by periods of rapid change

Evolution has scientific evidence and explanations

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Evidence is found in fossil records, comparative structures, and through DNA analysis​

​Evidence of Evolution

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Multiple Choice

Due to pollution, a pond becomes darker over time. Which trait variation became more common?

• light fish

• dark fish

Multiple Choice

The theory of evolution by natural selection means that what is changing over time?

• The inherited traits of a population.
• The acquired traits of a population.
• Hair color and eye color
• Attractive features.

Multiple Choice

A yellow morph and green morph of an insect lives in the rainforest canopy. You would expect:

• the green population to increase and the yellow to decrease

• both populations should stay the same

• both populations will increase

• the green population to decrease and the yellow to increaseThis is a wrong answer

Multiple Choice

How do fossils provide evidence that evolution has happened on Earth?

• Fossils show how the sizes of certain animals has changed drastically over millions of years
• Fossils show that some species have gone extinct
• Fossils show how life forms present today are different than those from the past
• Different sedimentary rock layers provide evidence for how the environment has changed over time

Multiple Choice

Similarities in bone arrangements, like those in the picture, support the hypothesis that...

• these organisms are not well adapted

• these organisms share a common ancestor

• these organisms all share the same DNA sequences

• these organisms are members of the same species

Multiple Choice

Structures are similar in appearance but not in structure

• Vestigial 
• Homologous 
• Analogous Structures 
• Embryonic 

Multiple Choice

If two organisms have similar traits of DNA they are probably

• share a common ancestor
• share a common environment
• share a common population
• speciation

Multiple Choice

Researchers discovered that the legs of birds are homologous to the feet of reptiles. Which claim is BEST supported by this fact?

• Birds do not require legs

• Birds and reptiles have a common ancestor

• They randomly developed the same structures

• Selection pressures have acted on birds, but not on reptiles

Multiple Choice

Hummingbirds have a beak just the right length to reach the nectar in a cardinal flower and as they feed their foreheads bump into the pollen structure. Cardinal flowers are red which hummingbirds can see but bees can’t. Cardinal flower’s pollen structure is just the right length for the hummingbird to pick up pollen as it feeds

• Convergent

• Divergent

• Coevolution

Multiple Choice

In the ocean surrounding Antarctica, there are fish that survive the cold water by using a molecule made of glycoproteins that circulates the blood and keeps it from freezing. Certain kinds of worms that live in the Arctic ocean also make antifreeze proteins that help them live in icy water.

• Convergent Evolution

• Divergent Evolution

• Coevolution

Multiple Choice

The Galápagos tortoises share a common ancestor, but have necks of different lengths to best reach the food they need in their environment.

• Convergent

• Divergent

• Coevolution

Interactions within & among populations include:

• carrying capacities

• limiting factors (selection pressures), &

• ​growth curves

​Some text here about the topic of discussion.

​Ecology

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​In nature no species exists in total isolation – all organisms interact with both the abiotic environment and other organisms

• If two species interact directly within a shared environment, they share a positive association (they co-exist)

• If interactions within an environment are mutually detrimental to both species, they share a negative association (do not co-exist)

​​Predator-Prey

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​​Symbiosis

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Nutrients and energy cycle through ecosystems​

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Producers are always at the bottom of a​ food pyramid/energy pyramid

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Consumers can​ function at multiple levels in a food web

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​Energy Flow

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​Nutrients refer to the material required by an organism, and include elements such as carbon, nitrogen and phosphorus

• The supply of inorganic nutrients on Earth is finite – new elements cannot simply be created and so are in limited supply

​Hence chemical elements are constantly recycled after they are used:

• Autotrophs obtain inorganic nutrients from the air, water and soil and convert them into organic compounds

• Heterotrophs ingest these organic compounds and use them for growth and respiration, releasing inorganic byproducts

• When organisms die, microbes decompose the remains and free inorganic materials into the soil

• The return of inorganic nutrients to the soil ensures the continual supply of raw materials for the autotrophs 

Carbon Cycle

​​Nitrogen Cycle

Water Cycle

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Changes in the communities in ecosystems

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Primary - no soil

Secondary - soil remains​

​Ecological Succession

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Multiple Choice

All these organisms share the same

• Biome
• Population
• Community
• Habitat

Multiple Choice

Bacteria which convert nitrogen gas into bio-available forms of nitrogen, such as ammonia and nitrate, are known as _____

• De-nitrification bacteria 
• Nitrogen fixing bacteria
• Oxidizers
• Buffers

Multiple Choice

An organism's place in the biotic environment and its role in an ecosystem is

• Niche

• Epitope

• Habitat

• Habit

Multiple Choice

Members of a species in a defined area

• Ecosystem
• community
• biodiversity
• population

Multiple Choice

What may happen if the snowshoe hare was removed from the food web pictured?

• The insects in the habitat would increase.
• The shrew population would decrease due to being only hawk food source.
• The willow tree population would decrease.
• Foxes would dies due to no food source. 

Multiple Choice

In the energy pyramid here, how much of the energy in the producers gets passed to the herbivores?

• 10%
• 20%
• 80%
• 90%

Multiple Choice

Which of the following leads to a decrease in biodiversity?

• protection of ecosystems
• pollution control
• selective cutting
• introduction of exotic or invasive species

Multiple Choice

In the food web shown, the snail would be considered...

• primary consumer
• secondary consumer
• tertiary consumer
• producer

Multiple Choice

If a scientist in New Zealand was studying how a group of herbivores interacted with a group of omnivores, and all of their abiotic surroundings, what level of ecology would she be studying?

• Community

• Population

• Species

• Ecosystem

• Biome

Multiple Choice

All energy on Earth ultimately comes from what source?

• Water
• Sun
• Consumers
• Oxygen

Multiple Choice

Plants obtain light from the sun to make food during _______________.

• respiration

• pollination

• reproduction

• photosynthesis

Multiple Choice

Is soil a biotic or abiotic factor?

• biotic

• abiotic

Multiple Choice

Is pH a biotic or abiotic factor?

• biotic

• abiotic

Multiple Choice

What is the carrying capacity of the graph?

• 1000

• 8000

• 800

• 600

Multiple Choice

Which of the following would INCREASE the carrying capacity of an ecosystem?

• increase in predators
• disease
• increase in available food
• drought

Multiple Choice

If a disease destroying barley plants in a field swept through an ecosystem, what would happen to the barley eating bird population in the the field ?

• The bird population would stay the same
• The bird population would infinitely increase
• The bird population would decrease

Multiple Choice

A scientist was studying a population of fish in a pond over a period of 10 years. He observed that the population increased each year for 3 years, and then remained nearly constant for the rest of the study. The best explanation for this observation is that the population had

• stopped reproducing

• reached carrying capacity

• mutated into a different species

• run out of food and all died