KAUNG'S COMPLETE SCIENCE - ACADEC - '24-'25

What are the different ways biodiversity can be measured?

1. Variety of species

2. Variety of genes

3. Different ways groups of species are organized together on the planet.

4. Different combinations of living and nonliving components

How many genes do humans have?

30,000

Who eats dozens, or hundreds of species?

Ancestors and hunter-gatherers

What are the 2 types of value?

Instrumental and intrinsic motivation

Some traits are controlled by a single ______ but more complex traits are controlled by ________

a single gene, but more complex traits are controlled by more genes

What is an individual's phenotype?

All of an individual's anatomical, physiological, and behavioral characteristics

In a pea plant, the A genotype is for what color and the B genotype is for what?

Purple and white, respectively (for flowers)

What species exhibit incomplete dominance

snapdragon flower (A for red, B for white, AB for pink)

For peas is smooth or wrinkled dominant?

Smooth

What did Mendel call a gene?

A hereditary factor

What species do toy poodles and Great Danes come from?

Canis familiaris after artificial selection.

Mutations are more likely to occur under exposure to

anthropogenic chemicals like smoke and radiation

For complex traits, phenotype is a result of

Environment and Genotype

What century and what nationality was Mendel?

19th century, Austrian monk

What are the 4 types of genotypic diversity?

1. Variation within individual organisms

2. Variation among individuals within a population

3. Variation among populations (same species that have been isolated )

4. Variation among species.

Species diversity results from both ______ and ______ processes

Adaptive and nonadaptive

Most new species arise through process that take place at the ________ level

population

What is Fitness/

Measure of ability to survive (viability) and reproduce (fertility)

What does sickle-cell disease do?

Reduces oxygen-carrying of blood and ersult in severe mental and physical impairments and death (especially in people of African descent)

What does the sickle cell allele convey resistance to?

malaria

How old was Darwin when going aboard the HMS beagle

Age 22

What was the HMS Beagle to do? What role did Darwin serve?

To sail around the world, the ship's naturalist.

When did Darwin publish "The Orgin of Species by Means of Natural Selection"?

1859

Key ideas of natural selection

1. Organisms produce many more offspring than are needed to replace the parents.

2. Individuals differ in phenotype within a species.

3. In a given environment, some phenotypes enable better fitness

4. The fitter individuals will have a better chance of reproducing and propagating their genes.

The process of becoming most fit or most suited for an environment is called

adaptation

Adaptations of plants to dryness

Thick, fleshy leaves with thick waxy surfaces that allow conservation of water.

What are the nonadaptive Evolutionary processes?

Gene flow and genetic drift

When is there a high rate of gene flow?

When the dispersal rate of the species is high

What is genetic drift?

random change in allele frequency in small populations

What is an example of the bottleneck effect

Cheetah hunting: the population is now so small that genetic variation is non-existent, all cheetahs are basically identical twins.

They also now have low fertility (70% abnormal sperm cells) and high rates of disease in zoo settings.

3 factors affecting the pace of evolution

1. Rate of environmental change

2. Size of population

3. If the beneficial allele already exists or has to come to by means of a mutation

What is the ultimate source of biodiversity

Genetic diversity

What time period was the HMS Beagle?

From 1831 to 1836

When an environment changes so that a population is no longer adapted to it?

The population growth rate becomes negative

When the population gowth rate becomes negative, what must the population do? Why does it not work in most cases?

It must either migrate to suitable environment or adapt.

This doesn't work because areas are usually already inhabited or there are no suitable areas, and the changes usually occur too rapidly for evolutionary processes.

Most of what we know about hte evolution of life is based on what?

Fossils

Do organims decompose quickly or slowly

rapidly fairly

Usually, what of the remains of organisms is left over?

Usually, nothing is left behind but sometimes sediment protects the hard parts like bones (and occasionally softer parts) that turns into fossils.

The fossil record is the basis of the

geologic time scale

What is the geologic time scale:?

It divides time into various intervals from the formation of the Earth through the present with distinctive events such as evolution of multicellular organisms or extinction events characterizing the major time intervals.

How many years ago in the fossil record do bacteria appear?

3.5 billion years ago

How many years ago are multicellular and shelled organisms visible in the fossil record?

540 million years ago

Identifiable speices are usually found in the fossil record around

1 (mammals) -10 million(marine and clams)years ago

The ginkgo tee

Chinese tee/ ornamental US tree that appears in the fossil record 60 million years ago

What has been the source for most of our knowledge of extinction?

The fossil record

All species eventually

go extinct

The greatest mass extinction is in

the end of the Paleozoic Era, when 90-95% of marine species and 70% of land vertebrates went extinct

Why did the Paleozoic Era extinction happen?

The shutdown of ocean circulation and the eruption of the Siberian Traps

When was the extinction of the dinosaurs?

65 million years ago

What is the extinction of the dinosaurs called?

KT boundary, Cretaceus, Tertiary Period boundary

What species survived the KT boundary?

Mammalian rodent species that would give rise to the human species

What problem do we run into when estimating extinction rates and how do we solve it?

That we don't even know how many species there are in the world.

We solve it using species-area relationship

What was the species area relationship initially used for?

To show why larger islands had more species than smaller ones.

The Tropical rainforest has a minimum of how many sepecies?

10 million

What is the term for the number (not diversity) of species in a given area?

Species richness

Formula for species area relationship

S = cA^z

When did scientists began to agree that we are in a mass extinction event?

1990s and the 21st century

The last 5 mass extihnctions had occurred __________ over the last _______ years

sporadically over the last 450 million years

The recovery of biodiversity from mass extinctions take

10 to 100 million year

How do human activity alter biodiversity?

1. Direct removal (overexploitation)

2. Habitat loss

3. Habitat fragmentation and modification

How did the Dodo go extinct?

Overhunting (it was large and flightless and therefore was an easy source of meat) and introduction of competing for food species by Europeans

Where did the Dodo Bird live?

In the Indian Ocean Island of Mauritius

When did the Dodo go extinct?

17th century.

How does Habitat Fragmentation affect biodiversity

1. Less contiguous space for species like mountain lions, wolves and tigers

2. Edge habitat organisms have a greater effect

3. Lack of migration and therefore gene flow, and fragmentation of populations into small populations, which leads to genetic drift and loss of genetic variety

Examples of animals that thrive in edge habitats?

Raccoons and Skunks

What are exotic species

species that have been moved by humans to a different location.

What in ships create exotic species?

The ballast water

Example of an exotic species?

The zebra mussel from Caspian Sea in Asia to the Great Lakes and Canada in the 1980s

What did the zebra mussel do?

Depleted food supplies, clogged water valves because it has no natural predator

Is it easy to control an invasive species?

No

What provides the first step in understanding why some species are found or not found in various regions?

Evolutionary history and Ecological processes

What is ecology

The study of the relationship between organisms and their environment

What are "relationships" in ecology

factors affecting survival such as adaptation, prey-predato, flow of carbon, etc.

In Individual Ecology, what 3 things are critical?

Conditions, Resources, and Habitat

What are conditions?

chemical or physical factors in the environment that influences survival and growth.

What conditions are important for terrestrial systems? (5)

1. Solar radiation

2. Temp of air and soil

3. Amount of precipitation

4. Soil type

5. Quality of nutrients such as nitrogen and phosphorous

What conditions are important for aquatic systems (5)

1. Solar radiation

2. Temperature

3. pH level

4. Salinity

5. amount of oxygen in the water

These vary with:

Location in the stream

elevation

latitude

Examples of organisms that can survive, grow and reproduce under any environmental condition?

1. Bacteria and microbes

2. Plants

3.Insects

4. Invertebrates

5. Some birds

6. Some mammals

7. Fish in harsh oceans

Baobab tree

East Africa, sheds leaves in summer to preserve water from stomata and grows new leaves in the rain season

What are the 2 most important abiotic environmental conditions?

Solar radiation and moisture

What index measures both solar radiation and moisture

Evapotranspiration

Amount of water loss depends on how much water there is and the rate of evapotranspiration (which depends on solar radiation)

What is a species' range of tolerance?

The range within which it can exist

How does extremity affect a species ability to survive, grow and reproduce?

As conditions worsens, it won't be able to reproduce, grow and eventually survive in that order

What is the difference between environmental conditions and resources?

That resources are consumed and are competitive

What is important at all levels of ecology?

Resources

Why is it that although more species should exist with more resources, but there is little direct correlation, and give example?

Because of environmental conditions

Salt marshes from Georgia to Cape Cod

What functions do salt marshes have?

1. collection of nutrients for many fish and shellfish

2. source of energy for the ocean/marine habitats adjacent to it.

environmental conditions of salt marshes

1. Salt marshes have both high and low water levels, and both high and low salinities

2. Salt marshes also have low oxygen soils because of the microbes

3. Microbial activity also produces toxins

How do grasses in salt marshes adapt?

They have tissues that excrete excess salt and air chambers in their roots that produce their own oxygen-rich microhabitats around them.

A possible adaptation to the environment involves a change in allocation of _________

energy

How much of the population does a few grass species make up in salt marshes?

95% of the total biomass

What factor is most likely to increase the probability of extinction?

A small population

What aspects of populations do ecologists focus on?

1. Interactions with abiotic factors

2. Interactions with own species

3. Interactions with otheer species

Who discovered logistic growth and when?

1932, Georgy Gause

What nationality was George Gause?

Russian biologist

Describe Gause's experiment?

5 cm3 tube with an ideal environment (constant amount of food, good chemical and temperature environment and waste being flushed out) for 20 Paramecium except space.

What is another name for logistic growth model

Density-dependent growth

As number of population increases, birht rate ____ and death rate ____

birth rate decreases and death rate increases

What are the assumptions of the logistic growth model?

1. Stable age distribution

2. Population density is measured with appropriate units

3. Relationship between growth rate and population density if linear

4. No time lags.

__________ populations in nature violate ________ of these assumptions

Many populations in nature violate one or all of these assumptions