Cells and Evolution

What are the 4 things that all organisms need?

They need water, nutrients, space, and air (CO2 and O2)

What are the 8 characteristics of life?

“Cool Hippos Eat Really Tasty Green Red Cherries”

Cells, Homeostasis, Energy, Reproduce, Traits, Growth, Respond, Change

What is Homeostasis?

What do humans do to maintain it in hot and cold conditions?

Homeostasis: ability to maintain internal conditions in response to environmental changes

Humans shiver in the cold and sweat in the heat

What is stimulus?

Any activity that brings about a response

Ex: Hunger (stimulus) → you find something to eat (response)

What does it mean for an organism to grow?

By cells increasing in number or size

Plants use photosynthesis.

Do both Plants and Animals need cellular respiration?

Yes.

How are tissues organized?

They are groups of cells, similar in shape and function.

How are organs organized?

They are tissues organized into larger structures

Do unicellular organisms have cell specialization?

No. Because they are composed of one cell rhat has to carry out all the functions essential to their life.

Do unicellular organisms have tissues?

No. Only multicellular organisms can have tissue, considering tissue is made from groups of cells which cannot be found in a unicellular organism.

Do prokaryotes have membrane-bound organelles?

No.

Are eukaryotes restricted to being unicellular organisms?

No. They can be either multicellular or unicellular whilst prokaryotes are strictly unicellular.

What is the difference between cell differentiation and cell specialization?

Cell differentiation is the process here stem cells develop into specific types of cells with different structures and jobs. Cell specialization is the end result of this process, after each cell has its own unique structure and function.

What process is responsible for cell differentiation?

Gene expression: a process in which a gene is switched on or off for a cell, resulting in different protein being made and different structures and functions for cells.

What are stem cells?

Cells that have not undergone cell differentiation yet.

What are the uses of stem cells?

Repair damaged organs, cure some diseases, and potentially regrow lost limbs in the future.

What is photosynthesis and cellular respiration?

Photosynthesis: chemical process in which plants uses sunlight to produce energy

Cellular respiration: process in which sorted energy is broken down to release energy

What is the input for photosynthesis and cellular respiration?

Photosynthesis: CO2 and H2O

Respiration: Glucose and Oxygen

What is an adaptation?

A characteristic that helps and organism survive and reproduce in its environment.

Is hibernating during the winter an example of a behaviour or structure?

Behaviour.

Name an adaptation for a snake

Can unhinge it’s jaw

Name an adaptation for an elephant

Has a trunk it uses to bathe, wash, and drink

Name an adaptation for a monkey.

Has opposable thumbs to grasp objects.

Name an adaptation for a spider.

Can easily sense vibrations in the ground.

How is the origin of species hypothesis 1 wrong?

It contradicts new, observable, scientific evidence we have.

What is the “Law of Use & Disuse” and the “Inheritance of Acquired Characteristics?”

1. The more often a body part is used, the more developed it will be

2. The more developed or underdeveloped traits are pass onto parents children.

What is Darwin’s theory of evolution?

Natural selection: phenomenon occurring where organisms possessing traits that are highly suited for their environment have a greater likelihood of survival and a higher rate of reproductive success.

What are the 4 conditions necessary for natural selection to occur?

1. Struggle for survival

2. Inheritable variation

3. Variation of fitness

4. Lots of time

Define variation of fitness.

Fitness is defined by an organism’s ability to produce offspring, so the greater number of offspring an organism can produce, the higher its level of fitness.

Define inheritable variation.

That within a population, organisms will exhibit slight differences due to variations in the genes.

What happens when two distinct species produce offspring?

They produce an infertile hybrid

Define evolution.

Evolution: the gradual process of change that takes place over many generations, during which organisms slowly change some of their physical and behavioural characteristics.

Define convergent evolution

When two or more species share similar traits but no common ancestor

Define coevolution.

When two or more species influence each other’s evolution because of their interaction between each other.

What is an allele and how do new ones appear?

Allele: variation of a gene

New Alleles appear via mutations in the gene pool of a population

What decides whether mutation is harmful or beneficial?

The environment

What are the four factors that affect the frequency of alleles in gene pools

1. Natural selection

2. Gene flow

3. Genetic drift

4. Inbreeding

Define genetic drift.

It is a change in a population’s gene pool by random chance. Like natural disasters.

What is a deleterious allele?

A recessive allele that makes an animal less “fit”

What are the 5 types of evidence for evolution?

1. Homologous structures

2. Vestigial structures

3. DNA evidence

4. Embryological development

5. Fossil record

What is the difference between homologous and vestigial structures?

Homologous: similar in structure, same origins, different functions

Vestigial: have been reduced in size and function, may have once been used, complete, and functional.

What does a fossil record do?

Gives us a time scale of how long evolution takes

Also shows similarities between extinct and living animals

What does punctuated equilibrium suggest?

Suggests that species often experience long periods where almost no change occurs, punctuated by relatively short but rapid periods of change.

Are you ready?

Yes.